Важно: всем у кого проблемы с тормазами

Ответ: Важно: всем у кого проблемы с тормазами

[size=+1]UFO/Internal Calipers[/size]





Here's my collection of posts re: UFO brake upgrades for the '91 200q and early V8q.
Chris Miller, Windham NH, c1j1miller@aol.com
Note that I haven't done anything to upgrade my car... My UFOs work great.

UFO brakes are the unique internal caliper disc brakes developed by Audi for the '90-'91 V8, and the '91 200q. They are nicknamed UFO because of the appearance of the brake rotor. On UFO equipped cars, looking at the front wheels, you can see the metal basket that connects the rotor to the wheel hub.

The concept was that by mounting the caliper assembly inboard instead of outboard, you could get more braking area with a larger diameter disc without using a 16 inch wheel. Audi wanted to keep the unsprung mass low as well as increase the choices of tires available, and retain the larger sidewall on a 15 vs. 16 inch tire, which increases comfort.


The 91 200tq and the 90/91 v8s had a 12.2 inch front disc with pretty awesome stopping power. A downside of this design is difficulty in finding wheels that fit. Much more seriously, the radical design had serious cooling problems. Many of these cars suffered from warped front discs after just 20k miles. Audi offered to replace the UFOs with regular 5000/200tq discs and in some cases the G60 S4 disks, but only after a history of warped rotors on a car. This was to prevent expensive and frequent replacement of the front discs.

The replacement involved replacing the entire front suspension. The retrofitted cars do lose some braking power as the regular discs are only 10.9 inches in diameter (about 17% less swept area than UFOs).
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Change brake proportioning to use more rear brakes



One of the suggested procedures with UFOs is to adjust the stock brake pressure regulator for the rear brakes to give more bias to the rear wheels. This device adjusts rear brake balance based on rear suspension loading (i.e., more braking when the trunk is full).

Keith Anderson at http://www.karquattro.com/ also apparently sells a nice adjustable brake bias valve, if yours needs to be replaced.
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Fix your warped rotors



The infamous Qlist fix for warped rotors: Get up to 80 mph, stop quickly, and repeat two more times in succession. Then, let them cool down slowly while driving. This should get them red hot, and relieve any internal stresses. Works pretty well for most people.

[size=+1]Turning UFO rotors[/size]

You can also true your rotors using an on-the-car turning machine (per Bentley, below), or devise a way to turn the rotors as Wolf did: http://www.succulents.com/quattro/ufo.html
----------------



The cat is hereby out of the bag regarding a consistent source for getting UFOs turned. I had 6 of mine done one year/30K miles ago. The 1st set ran fine for ~6 mo. I just mounted the 2nd set last week and they are running true. Don in Kansas City had 2 done ~ November and they were still true a month later, sooooo,

You can get UFOs turned at:

Modern Machine Company
1633 Old Bayshore Highway
San Jose, CA 95112-4305
1 (408) 436-7670
Attn: Ed
Hrs: 7:00 - 5:30 pt

Ed was my contact when my 6 were done on March 3, 1999 (although he wasn't the guy who actually ran the lathe.) He'll know to have just enough material removed to get "100% cleanup", and to stop the inside cut exactly at the outer edge so as to not nick the inside of the sheet steel that holds the cast iron rotor (that would ruin the entire rotor, I believe.)

They removed less than .015" from each of mine (far less than I expected.) Bear in mind that the new spec/wear limits are 25/23mm (.984/.906") respectively. Warped UFOs run out of square anywhere from .002 to .007 TIR (worst I've measured) so a new UFO is good for a few Wolff-turns before it reaches its wear limit. They need to be thicker than ~.925 to be turned without exceeding the wear limit, so measure before you ship.

Ed should have the tooling from March '99 when he made it for my UFOs; all he has to do is mount it and take a skim cut to square it to the lathe axis. He was verrry pleasant to deal with (as are so many machinists I've known.) Price should be ~$50.00 each in quantity of 2; maybe less for more. Call first to confirm this and shipping arrangements.

However you ship yours, the return shipping price will be the same as getting them there, so you can add that to your bill and they'll pay it, or have 'em ship COD and pay when they return to you.

FWIW, UFOs package neatly two at a time into a 4 gallon paint/stain box that opens on the top (not the end) with a layer of old carpet padding on the bottom and between 'em that extends around their edges. That works well for hand carrying/delivery and for storage of spares at home. If you're shipping 'em from out of town you could put that box inside another larger one with foam peanuts or such between the two boxes. I don't know how Don packaged his.

I hope that covers everything. If you can think of anything I forgot, let me know, and let the list know if you do this and how it worked out.

Good luck and I hope this lasts,

Steve

-------------------------------
Subject: Re: Wolff-turning UFOs in San Jose

thanks again for the info. so far the turned ufos are working great. they charged me $100 to do the pair. wonderful people to do business with. being skeptical it might not work I installed a used set of pads (plenty of miles left on them) and after about a month everything is still perfect. its good to have a solid pedal again. it cost me $60 shipping.

have a good holiday and happy motoring. its beginning to look like quattro weather.

Don Lillig
kansas city

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From Bentley, with comments



Subject: UFO Brakes
After the recent discussions about UFO's, I looked them up in the Bently for the first time. Couple interesting things to report: Brake Caliper - the outline drawing says "cannot be repaired, replace if necessary"...that seems kinda weird, you can't overhaul them? Anybody ever try? There is a section on "Steering Wheel Shimmy During Braking", it has three things you can do to fix it (they are outlined in this order):



CHECK CONTROL ARM BUSHINGS 1. Remove wheels, disconnect brake pad sensors, remove front pads, remove calipers, but do not disconnect. 2. If you have less than 40K on your car, inspect the inner and outer control arm bushings for cracking, splitting and deterioration. 3. Replace as necessary. 4. If you have more than 40K on your car, replace both front inner and outer front control arm bushings. For those who don't know what a control arm bushing is, it's the bar that the front sway bar and lower ball joint are attached to. The bushings that they are talking about are where the sway bar goes through the control arm, and where the control arm attaches to the subframe (I think subframe is the correct term) of the car.

TRUING OF FRONT BRAKE ROTORS 1. True front brake rotors with an on-the-car brake lathe. 2. Note: if an on-the-car brake lathe is not available, replace rotors. (see here for a method to turn them: http://www.digiweb.com/~wolffb/quattro/ufo.html) 3. FYI - brake disc thickness new 25 mm (0.750"), brake disc wear thickness - 23mm (0.690")

WHEN NEW BRAKE ROTORS ARE REQUIRED 1. Thoroughly clean contact surfaces of brake rotor and hub. 2. Install using all lug bolts with suitable spacers. 3. Tighten lug bolts diagonally in stages to 29 lb-ft. 4. Attach dial indicator to measure brake rotor runout. 5. Rotate rotor and record runout. 6. Remove brake rotor and remount after rotating rotor to next lug bolt hole. 7. Check rotor runout. 8. Continue remounting rotor checking runout at each lug bolt position. ---- Maximum rotor runout 0.06mm (0.002") 9. Mount rotor in position where lowest runout was achieved. 10. Mark hub and rotor with center punch as mounted in lowest running position.

MORALE OF THE STORY >From what I can see, if you car has front end shimmy, I would first check brake rotor runout and determine what it is, maximum new is 0.002", I wouldn't want to go past 0.004" or maybe 0.006"? If rotor runout is acceptable, go after your bushings. If you are going to go in and do a brake job, why not replace the bushings as a matter of good maintenance practices. I doubt they cost very much, especially when comparing them to the price of rotors and pads. This procedure will help you determine the root cause of the problem so you can then fix it!

Paul Waterloo Colchester, CT 91 200q EMAIL: 74543.407@compuserve.com

Response: Those control arm bushings are BONDED to the control arm which is a $125 part per side......... Later! Eric Fletcher '87 5KCSTQIA2RSR2B St. Louis, MO STEADIRIC@aol.com
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Alignment and bushing replacement



VERY COMMON 44 chassis AUDI PROBLEM
3 replacement items, do now
1) REPLACE UPPER STRUT BEARING ~25ea
2) REPLACE INNER CONTROL ARM BUSHINGS (GPR sometimes has better prices for the whole arm than the dealer for the bushing) ~80 -100ea
3) REPLACE SWAY BAR BUSHINGS X 6 ~50.00 total
4) OPTIONAL (complete the project) - TIE ROD ENDS ~30EA Align to factory specs, camber at .5 neg. If you can't get .5 neg on both fronts, chances are you have a bad strut.

The sway bar and the control arm bushings triangulate the control arm, and are critical to proper alignment. Assuming you get the whole control arm, this project is doable in the garage in less than 4 hours coffee to beer.
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Maintaining the UFOs



Fellow Audians; I had an interesting conversation with Dan (THE MAN) Simoes own mechanic the other day about UFO brakes. Mr. Greg Haymann of the Autofirm (914.855.0170) say they need not be problematic. He states:

1) There is a brake bias adjustment valve at the rear of the cars that requires a pressure gauge for appropriate adjustment and you never can have too much rearward bias;

2) Change the brake fluid once a year at the beginning of summer;

3) Keep the front mounting hubs rust free and as clean as possible;

4) Make sure the brake duct/cooling vents are wide open (they tend to close up a bit (look under the front bumper for the air flow entry points).

Usual disclaimers and all that. Greg
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Sources for pads and rotors for UFOs



Pads: You can send a set of (UFO) backing plates to Carbo Tech in Fl. and they can
put whatever kind of pad compound you want on them.

CarboTech Engineering
1080 N.W. 53rd St.
Ft. Lauderdale, FL 33309
954.493.9669

===============
Linda @ Carlsen Audi in California has the "hardened" UFO rotors for $275.00/each. Mention the Quattro List.
-------
Pads for the UFOs are down to $89 for REMZAs from BLAUfergnugen in Manitowoc, WI. Their number is 920-758-3232. http://www.audiquattroparts.com.

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[size=+1]Brake upgrades[/size]



Retrofit to G60 Calipers
------------------
If you've got the conversion to G60 calipers, the pad backing plate is
FMSI-419. Basic pads (street) are available from a number of sources,
including Halsey (portland) and Parts Connection (Fresno). Brands you
might get: Jurid, Textar, Ferodo (3411 compound was the original UFO
conversion pad--very black & dusty) You may not get the right electrical
connector for the pad wear sensor (cut off the old one and splice it into
the new pad's sensor). Other brands available: PBR (?), Porterfield
(street compound R4S--on my car now, also a track compound R4), Cool Carbon
(whoever replaced them), PowrPad (like CC & Porterfield), Pagid (had them,
great brakes, but $$$).

HTH
--Linus

Custom caliper upgrades
-----------------------
A group of audi enthusiests are developing custom braking kits based off the Porsche Boxter and Carrera monoblock alluminum calipers used on the '99 model cars. They're manufacturing a custom mounting bracket, and sticking with factory porsche or audi parts for the rest. See http://www.bira.org for more details.
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Date: Mon, 30 Jun 1997 23:25:32 -0400 (EDT) From: Hulda Jowett <hjowett-at-nasc.mass.edu>
Subject: Re: UFO Brake Conversion Kit for V8Q
I recently sent my hub/wheel assembly out to a company called Cooltec. They specialize in big brake conversions for all cars, though they mostly deal with the higher end stuff like Porsche racing brakes and such. For an estimated $1300, this co. will CNC machine custom brackets to mount some good sized Brembo four pot calipers. They will mount over some 12" x 1.25" rotors with custom machined T-6 aluminum hats (12" is all that will fit under my 16x7.5" wheels, 17" wheels will fit 13"!). The calipers are available in black, red (c'mon, you'all know you been lusting after those huge red Porsche brakes ever since the RS2 wagon appeared), and yellow. I don't know what others have seen for prices on brake kits, but this one for my Corrado VR6 costs about $1k less than cheapest kit I've found. It uses the same or better parts too (thicker rotors, Brembo calipers) The turn around time is about 1.5 to 2 weeks, though if they have the time, I'm sure they could do it more quikly. The more kits that you have made, the less expensive it is for all, as the set-up for machining the hats/caliper mounting brackets only has to be performed once. If anyone wants Cooltec's #, just ask. The guys who run the place are extremely helpful and knoledgable over the phone... Later, Brian
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another custom upgrade

Date: Tue, 01 Jul 1997 23:07:02 -0700 From: crossley family <crossley-at-northwest.com>
Subject: Re: UFO Brake Conversion Kit for V8Q
Gregory Owens wrote: > > Forgive me if this subject has been discussed before, but didn't find anything > on this in the archives. Does anyone know if there is an after market > conversion kit available for the UFO brakes on the V8Q? If not, can 17" > wheels be put on over a UFO brake? > > Thanks. > > Greg Owens > Seattle, WA 90 V8Q

Sorry, this is old stuff, but I know of no other way of doing this. Greg, The following is a post on the subject that I made about a month ago: >Well, it's done! My UFOs are history and, so far, I am elated! With the help of Scott Mockry and John Karasaki, my '91 200q has been transformed from a shakin', vibratin' beast into smooth stopping son- of-a-gun. After a couple of false starts due to rotor hat and caliper mounting bracket dimensional problems, the KVR Performance, AP Racing caliper based system was installed. The system, as finalized, is a bolt on resolution to the infamous Ingolstadt brake mistake. I haven't had an opportunity to drive the car really hard as in a track experience, but after a couple consecutive near 100 mph panic abs type stops today, I can only say "WOW!!". And the 314mm cross-drilled rotors and massive calipers look really cool inside those S4 wheels! I expect to keep hammering these brakes, as that was part of the deal I made with Terry Gosse at KVR, my car being a test bed for this system. I will post any new developments.> The system is working very well. I believe that the final developed price will be about the same that TAP currently charges for their 330mm system as they share the same caliper and nearly the same rotors. KVR builds those units for TAP. The July EC TAP ad lists the price at $2250. If you'r interested, call Terry Gosse at KVR Performance in Ottawa, Ontario at 1 800 636 0854. He is a real nice fellow and knows an awful lot about Audis and brakes. Kent Crossley, Portland, Or. '91 200q, IA stg 3 ecu, with real brakes (mine) '93 90CSq, looking for 15" snow wheels (hers)
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Other sources for Upgrade Kits
"Mov'it," the German tuners who adapt Porsche 993tt "Big Red"calipers to, well, just about anything with wheels it turns out. Here is their S2 page, with some juicy pictures.
http://www.movit.de/htm/audis2.htm
They use the Ultimate Garage in NJ as a US vender.



------------------
Scott Justason (QSHIPQ-at-aol.com) sells a Big Red brake kit.

You need approx 2 7/8 minimum clearance from the face of the rotor to the inside of the spoke of the wheel. That really precludes using any stock config wheel IMO. Some 17's will fit, and just about all 16's don't (exceptions so noted) without a smaller rotor.

I do them using 13.0-13.2rotors 1.25 thick. What you need to keep an eye on with anything less is that your pad covers the rotor. Remember, the stock porsche 993tt used a mongo rotor, and a lot of the design in that caliper assumes that big rotor.So, going smaller, I would want to make sure that the pad hits the rotor, and that can get tricky without btdt. I've had 30mm offset 17's work with aCompomotive wheel, and 24mm offset on all others. For bux considerations, the Hokenheim R is probably the best wheel for this conversion. BTW, this is theUrq offset wheel stock and available.

Regarding the pads. I don't recommend anything but the stock Porsche pads,they are more than enough for just about any audi application. Big Reds REQUIRE, absolutely, positively NO exceptions, ABS. When I do these conversions I disable the Antilock Off feature. Another warning, a low battery voltage can render ABS useless, btdt. You will easily spin the car on anything less than dry pavement otherwise. Most stock audi MC's will handle big reds front, stock rear. Increase the rear size (by only a little) and you will run out of MC. In fact, you will run out of MC upgrade as well, the answer is only duals. bux>up.

------------------
The Brembo brake site claims a comprehensive list of Audi applications. I don't know if they have one that would work or not.

http://www.brembo.com/
-----------------

Date: Fri, 22 May 1998 14:50:16 -0700
From: Ron Wood <vw-audisport-at-worldnet.att.net>
Subject: Wilwoods vs. Big Reds

There has been a lot of discussion on both sides of the fence
concerning the true path to brake nirvana. Having used the Wilwoods on
my Rally Quattro for two seasons gives me some experience with their
effectiveness & reliability. Although they see less miles than most
street cars, the conditions are certainly harsher (I hope) than what you
subject your street car to. So far, there have been no problems
whatsoever, with no annual rebuilds. I check them after every event &
there has bben no corrosion or leaking at all. Water & dust are a normal
conditions for the rallies & have not caused any problems, I tend to
think the will go at least 2 years on the street.
Brembo Big Reds are a very nice piece, no doubt about it. Do they
stop twice as well as a Wilwood or an AP-probably not. If you want the
most street friendly setup-use the Brembos. If you are willing to do a
little extra maintaince I think you will be happy with the Wilwoods. A
annual or bi-annual rebuild is not really a big job-a few hours of work
for a pretty big savings.
You can build your own kit & save money-time is involved to spec out
adadpters, etc. With the kits you are paying for someone else's time &
investment in designing all the pieces. Go ahead & do it
yourself-probably a lot more time involved than you realize.
Wilwoods are a very good part-check out how many pro race teams use
them, but they were designed as a race caliper, not a 100,000 mile
street caliper.
A good brake system is very important, especially so if horsepower
is to be upgraded. Unless you run at Bonneville, I think would worry
about brakes first. I havent met a stock Audi with enough brakes yet for
severe driving-street or otherwise. Good pads, slotted rotors, etc will
help, but, you can never have to much braking capacity.
Well thats enough for now-always open to other peoples experiences.
Ron Wood-Audis a plenty
82 URQ (will be getting Wilwoods w/ 330mm x 30 mm rotors in 16" wheel)
84 4KQ
85 4KQ
87 4KQ
87.5 CGT
8? Rally Quattro (Wilwoods w/ 300mm x 30mm in 15" wheels !!)
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From: "Frank Amoroso" <FAmoroso-at-svbank.com>
Date: Fri, 14 May 1999 14:59:00 -0700
(re: urS4/S6 brake upgrades from the G60s...)
Wow. There does seem to be some confusion on the list.

First and foremost, I am a brake zealot and I have inspected (both pre &
post installation) and driven the 3 major kits that are found on this list
(see FAQs), and I own the cj/sj kit and will hopefully soon have a Movit on
my Volvo. I think this gives me a unique perspective and knowledge base.
Although, I will add the hormone disclaimer... I am not harping on or
insulting any wankers and it is not my intention to rehash this info over
and over, however I spent a lot of time researching this stuff and I thought
I would try to make it easier for those seeking knowledge, so if you are
tired of this thread delete this post now, or without further adieu...

1) Go to http://www.ultimategarage.com and read everything under the big
brakes section, twice. Guido (Movit, Germany) has a great deal of knowledge
on the subject and as much btdt as well, I have corresponded with him and
Steve (ultimate garage) many times and they are straight shooters, in fact,
I'm trying to talk Guido to put a kit together for my T-5R (big yellows &
metal matrix rotors would be so tasty on a 3,300 lb car, but the 205/45-17
P-Zeros can't keep up, maybe a less powerful Boxster kit?) . This info,
especially the Movit FAQ will be a good place to start.

There are other great sites out there from which to garner information of
performance brake upgrades and I welcome you guys posting them up. In fact I
used to have the URL for a great Porsche shop that had tons of quality specs
and information on everything in the P-car braking system, does anyone know
the URL that I am referring to?

2) Granted there are many brake upgrades available from Hoppen's stock Audi
upgrades, and AP (KVR / TAP) as well as Alcon (Vortrag) kits, but let's
review the Porsche 993 tt caliper based kits. As we have seen, there are
mainly 3 Big Red (993.351.425.10) kits out there on this list (ie that list
members are using, most of them in CO, I might add). Here they are:

A) CJ/SJ : Big Red Calipers, pads, hardware, SS lines, 330 mm X 32 mm
Coleman rotors, aluminum mounting hats (rotor is thus 2 pieces, like the
Movit kit, this i) helps reduce overall weight and ii) helps reduce heat
transfer into the hub), aluminum caliper adapter blocks (note that these
blocks are HUGE, especially in comparison to the other kits, in a pinch they
can be used to bludgeon someone over the head with). This kit absolutely
requires 17" wheels, I have searched for 16" that fit, even custom and I
have been unable to identify any. Contact carl@info2000.net for more info.

B) Movit: Big Red Calipers, pads, hardware, SS lines, 322 mm X 32 mm Porsche
993 tt rotors, aluminum mounting hats, and steel caliper adapter blocks.
Some 16" wheels will work with this setup (S4 & S6 Avus) but will require
some combination of spacers / longer lug bolts. See URL above for more info.

C) Rev Sport: Big Red Calipers, pads, hardware, SS lines, 314 mm X 30 mm
Zimmerman (Euro A8) rotors, no mounting hats required for these rotors, they
are integral (1 piece rotor), cast iron, and have the appropriate bolt hole
spacing, etc., and steel caliper adapter blocks. This setup happily accepts
most 16" wheels. Call Dave at RevSport 719-471-4103 for more info (although
he is busy prepping cars for tomorrow's q-club event).

All of these kits can be had with pad wear sensors, etc. but I've kept the
comparison strictly to the relative performance bits & pieces.

2) As we have seen there are many pads that fit into Big Red
(993.351.425.10) calipers. The 993tt runs 993 351 949 00. I use the 928 pad
928.351.949.03 (manufactured by Textar) and its Textar equivalent, that is
the same pad except it is less than $100 for a set and comes in a yellow box
(I have the part # at home, if anyone wants). And we also know that there
are many aftermarket pads available.

I, like Jolly, thought I could improve performance so I have also run the
Porterfield R-4S pads, but I found them noisy, and dusty, for street
purposes, however they will go back in for the next track event. But, you
won't listen so you'll buy non factory pads in an attempt to "improve"
performance, you'll learn on your own.

Do what you will, with the above information, but spare me the attacks and
the ad hominum arguments (Wankers? Just for coming on the list and hyping up
a whole heated braking argument, then backing down and calling people names,
I'll leave you with another movie quote that I feel is quite apropos for
this whole mess, "Go ahead Meat, throw me that weak ass shit."). And no, it
isn't just about locking your brakes up (4 drums on a '70 Chevy C/K pickup
can do that), it has a lot more to do with being able to modulate said
lockup threshold, etc.

All,
I'll say it again, buy the Brake Performance Handbook, by Fred Puhn read it
read other reference materials, drive as many kits as you can and then make
your own decisions. Some of the things that have been posted up lead me to
believe that basic braking theory fundamentals need to be reviewed.

In the meantime, I will enjoy the setup I chose, based on MY needs and that
particular setup's value proposition.

Frank--

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[size=+1]Rear brakes[/size]



This weekend Peter Schulz showed me how to conduct periodic maintenance on
the one of the rear calipers on my 200q20v. The car had the typical
symptoms; braking seemed diminished; sticking rear parking brake.
Chock, jack, block, remove a rear wheel. Remove guide pins, clean, inspect
boots over guide pins. One of my guide pins was seized, as the rubber boot
had torn; cleaning and lubing restored it. Next year, new guide pins all
around.

Once the pins are removed, pull the floating caliper free, and hang it with a
wire or bungee for strain relief on the rubber brake line. Use the caliper
tool to turn the face of the caliper back in a ways. Remove the parking
brake return spring, then remove the retaining bolt for that spring. Pry the
parking brake lever down away from the caliper, and clean the shaft. I used
some very fine emery paper to remove corrosion, sprayed with brake cleaner,
then lubed it with a brake grease. Push the shaft back in place, reinstall
the spring and retaining bolt.

Pull the two pads off the caliper frame, and clean their mounting areas. One
of my pads was frozen in place. I cleaned the sliding portion of the backing
plate with a file, and scraped the corresponding area on the caliper. Put
the pads back, making sure the inner pad goes back on the inside...

Put the caliper back in place, put loctite on the guide pin retaining bolts,
and torque them back up. Pump the brakes a bit to reseat the caliper/pads.
Reinstall the wheel, torque up the bolts, lower and unblock car, then clean
up.

Probably an annual chore.

chris
--------------------------
I've had rear calipers apart on both my '875KTQ and the 200Q-20V and soon,
when I get around to it, the 90Q-20V. I don't try to remember little
specifics, but the overhaul is all straight forward, no suprises, just a
dirty brake job, type work. Cleaning out the gunk fixes the emergency brake
actuation system.

I'll pass along my brake hydraulics experience-based philosophy: When I
first take posession of a (used) car, I disassemble and clean all hydraulic
brake components, and blow out the lines. No need to buy repair kits, as
nothing will need replacing, (short of a torn boot), including leaking seal
rings. They will seal fine after proper cleaning,(I've never replaced one,
never had one leak). Do this and change hyd. fluid every year or two, and
you will never open the system again, even after 250K+ miles.

Bernie
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[size=+1]Brake bleeding[/size]



Here are two similar but different pressure bleeder methods:
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You can purchase a Brake Reservoir Cap Adapter from The Ultimate Garage
(http://www.ultimategarage.com). Price $30.00, or you can make your own out of an old cap and a screw-on tire valve.



To use this cap, purchase the following items:

1 - Quick Change adapter (sold by the air compressors in the tool department at Home depot - $4.00)

1 - 1 gal home garden sprayer (Home Depot - $11.00)

1 - Tractor tire air nipple (bolt down type that uses a nut and washers to seal the air in - NAPA auto parts $3.00)

1 - Liter of ATE Super Blue racing fluid (The Ultimate Garage - $10.00). This is available in either Blue or Amber; same stuff, just different color. It may be easier to switch color at each brake fluid change so that you know when the old fluid has been replaced by the new (alternate color) fluid.

Remove the spray hose from the home garden sprayer and attach an old air compressor hose in its place. Connect the Quick Change adapter to the other end of the air hose (this air hose still had the original hardware attached to the end). I then drilled a 5/8ths inch hole in to the top of the home garden sprayer and attached the tractor tire air nipple. Directions for use:

1) Attach the Brake Reservoir Cap Adapter to the brake reservoir. Also tie-wrap the cap and reservoir down to the MC.

2) Pour the brake fluid in to the home garden sprayer

3) Screw the pump back in to the sprayer

4) Pump up or charge (with an air compressor attached to the Tractor tire nipple) the sprayer with 10psi of pressure. (you can check this with a standard tire guage, on the tractor tire air nipple.

5) Attach the quick change adapter to the Brake Reservoir cap adapter. (I advise you put a large rag around this connection, before you disengage it.)

6) Loosen the first bleed screw and wait for the blue fluid to exit from the brakes. Quick tip: dispose of the "extra" brake fluid left over after the change. As brake fluid is hygroscopic, the open container is contaminated, and shouldn't be used later in the year when you're a little low due to pad wear. Buy an extra small-size container for use then.
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Here's a description of one poor-engineer's pressure bleeder:



1.The cap. Took the one from a 5000/100/200 P/S reservoir. It's the same cap as on the brake reservoir. I paid $5 at a junk yard. I took the float out and enlarged the hole to 0.476".Got a regular rubber tire stem (the narrow one, there are 2 different O.D.). Ran it trough the 0.476" hole. I also machined an Al ring and knurled it on the outside. I've put this ring over the cap w/epoxy, so it prevents the plastic cap from expanding under pressure and popping off the reservoir. I'd also recommend tie-wrapping the fluid reservoir down to the master cylinder, as it's only held on by a rubber fitting, and could pop loose.

2. The reservoir. Ordered a 1L chemical jar with a 110mm phenolic posin screw lid from Edmund Scientific. Drilled two 0.476" holes thru the lid, spaced 2" apart. Ran a tire stem thru one hole. Ran a chemical feed-thru union thru the other. Inserted a 0.25" hard plastic tube into union so that when the lid is screwed onto the jar the bottom tip of the tube touches the bottom of the jar in order to pick up brake fluid from the very bottom of the jar. To the other end of the union I connected a 1.5m Tygon hose with a quick disconnect for a tire stem on it's opposite end.

3. Pressure source. Took an old freon tank. Brazed a brass *T* to its valve. On that T installed a nipple for charging it from a regular shop air line, a pressure regulator with a dial gauge and a 1.5m Tygon hose with a quick disconnect for a tire stem.

Here's how I bleed the brakes:

1. Fill the car's brake fluid reservoir.

2. Screw the cap with tire stem on it.

3. Attach the quick disconnect from the jar lid to the tire stem.

4. Fill the jar with 1L of brake fluid. Screw the lid onto the jar.

5. Fill the modified freon tank with air to around 80psi.

6. Connect the quick disconnect from the freon tank to the tire stem on the jar's lid.

7. Adjust the air pressure to no more than 10psi! You can blow the seals with a higher pressure.

8. Bleed the clutch.

9. Bleed the wheels (RR, LR, RF, LF, RR).

Tips:

1. Test drive the bleeding sys with water first. A geiser of brake fluid WILL ruin your paint!

2. Keep a bucket of water handy for that inevidable spill-off. Should it ever happen to you (the cap pops off, the jar breaks - whatever, FLOOD the sucker with water!!! To repaint the car is a lot more expensive, than to rebleed the spoiled brake fluid.

3. Keep the jar in a container, when bleeding the brakes. I use an empty 1 gal tin (in which grocery stores sell olive oil).

4. Thoroughly cover the fenders with rags. If you spill brake fluid, you'll be glad you did cover them, coz you have about 20 sec to salvage your paint after which it's history.

5. Keep an eye on brake fluid level in the jar. If you miss and fill the MC and ABS unit with air, it will require rebleeding of the whole sys over again. No biggie, but it's time and brake fluid consuming.

6. Bleed the old fluid into a clear bottle of the same capacity as the jar - it will help you to determine how much fluid is left in the jar without having to crawl from under the car.

7. Bleed the old fluid out thru a clear Tygon hose (1/4" or 3/16 I.D. depending on the size of the bleeder screws). It will make bubbles visible.

8. Use only quality brake fluid. I like German Pentosin DOT-4. Some people on the list swear by ATE Racing Blue. Just don't use any Pep Toys, Quaker Trait and other no-name sh*t, it likes to ruin seals. The only acceptable domestic fluid would be Castrol LMA DOT-4. -

-- Igor Kessel'89 200TQ - 18psi (TAP)
'98 A4TQ
Philadelphia, PAUSA
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Brake Fluid

Subj: Re: [s-cars] Re: Brake Fluid
From: tedebearp-at-yahoo.com (Theodore Chen)



--- "ENGSTROM, GERALD" wrote:
> Just curious why not DOT 5 and what 5.1 is? Is 5.1 non-synthetic?

gerry, mail to you is bouncing. here's the response i tried to send you:

both are synthetic. DOT 5 is silicone-based, while DOT 5.1 is for fluids that meet DOT 5 specs but aren't silicone-based. the other DOT specs are basically just minimum dry and wet boiling points, but DOT 5 has become synonymous with "silicone". there are a number of race brake fluids that have very high dry boiling points, but only qualify as DOT 3 because their wet boiling points are nothing special.

in a nutshell, DOT 5 isn't really suitable for a car that actually gets driven. it's definitely not suitable for a car that gets driven hard or raced. first, silicone fluids have low lubricity. this increases the wear on sliding surfaces and may cause galling. second, while they don't absorb water, they don't stop it from getting into the system.
the water, instead of becoming absorbed by the brake fluid, will simply collect in the low points in the brake system. third, silicone fluids absorb air the way other brake fluids absorb water, and evolve the air at elevated temperatures that are well below the rated boiling point.

the fluid itself isn't boiling, but it's giving off bubbles and giving you a spongy pedal just the same. also, its viscosity at room temperature causes it to entrain air when you pour it, which means you're going to be pouring air bubbles into your brake system. i had a friend who tried to use this stuff in a race car, and was never able to get a decent pedal.

--- qshipq-at-aol.com wrote:
> Pantelis:
> Being intimately familiar with brakes, in all modded types , let me share
> some of my btdt. Bottom Line: IME, IF you feel that you need to go to a
> higher boiling point brake fluid, you have a heat problem, NOT a fluid
> problem.

with the setup you have, i agree with scott - assuming that your brake fluid has been flushed recently and that there are no air bubbles in it.

> As a rule, I use ATE Super Blue in my shop. Occasionally, Motul finds it's
> way into my bleeder (and since it's higher rated than the blue, I mix them
> without reservation) at track events or by "sales" of the stuff. That said,
> for a street car you shouldn't "need" more than the SB.

agreed.

> I've argued it this way to my customers many times: If you boil
> SB, you'll boil Motul, and you'll boil the 100USD/qt Nascar stuff too.

sorry, going to have to disagree here. the ATE SuperBlue isn't quite as good as the Motul 600. a fellow mustang racer who normally uses Motul 600 decided to try the ATE stuff because it comes in two colors (if you alternate colors, this makes it easy to tell when you get the old stuff out of the system) and because he got a deal on it. he didn't quite boil it, but he had a low pedal by the end of the day. he's gone back to Motul 600. i've also tried less expensive alternatives, such as Ford brake fluid (the stuff that comes in blue metal cans), which is actually Performance Friction fluid in a different container and has a boiling point of about 550 degrees.

no go - i boiled it. in fact, i spun on the last lap of the last race of the day when the pedal went to the floor. i'm going back to Motul.

but the Ford stuff is great for a street car. i've heard that Ford spec'd this brake fluid for the brain-dead lincoln town car drivers who ride the brake pedal.

as for the "NASCAR" stuff you mention, i suspect you're talking about Castrol SRF (Silicone Racing Fluid), which costs right around the amount you mentioned. super duper stuff. don't confuse it with DOT 5 silicone fluids. it has a boiling point around 500 degrees *Celsius*, doesn't absorb water, doesn't trap air, etc. only one catch: it eats seals, even viton. it's mainly used by well-funded teams who can afford to rebuild the brake system and replace all the seals frequently.

> The fact
> that you are boiling 600degree fluid means to me, that you would be wiser to
> spend your money on airflow, ducting, and maybe wheels and tires.

well, he said he was running DOT 4 fluid, which could be anything. DOT 4 requires about 450 deg. F dry boiling point. DOT 4 fluids also have a higher wet boiling point than DOT 3, but my experience has been that they tend to absorb water faster than DOT 3 as well. it's also not clear to me what type of fade he has: boiling fluid fade (soft and low pedal), or pad fade (hard and high pedal).

> A hot hard track day should see caliper temps in the 400-500 degree range
> max, not more than that.

where are you measuring the temperatures?

i've tried measuring caliper temperatures (while i was boiling the 550 deg. F ford brake fluid) with tempilabels and it didn't even register 350 degrees, which was the lowest temperature i had. i think it's localized boiling at the pistons. even though they're stainless steel, i suspect they're getting hot enough to boil the brake fluid. i've
got 4" brake ducts on my car, BTW.

> In your case, I'd first suggest changing to a cooler pad, I don't notice huge
> differences in the orange Pagids other than heat soak and initial bite (and
> they eat rotors faster).

i'd leave the pads alone until we know what kind of brake fade it is. there may be reasons to go to less aggressive brake pads, but brake fade isn't one of them.

> Bottom Line: The very last thing I would do is to change brake fluid.

actually, that would be the first thing i would do, if the brake fade were boiling fluid fade. it's the easiest approach, and the problem might be wet brake fluid, air in the system, or even incomplete flushing of the DOT 5 before putting in the DOT 4.

> Those silicone fluids do wear brake sealing components, and also need
> to be changed more frequently.

DOT 5 silicone fluids are innocuous if the car's just sitting there. however, they become corrosive toward brake seals when they get hot. more specifically, they leach the plasticizers out of nitrile rubber seals (which are very common in brake systems) and cause them to become brittle.

----------------------

> When you switched to DOT4, did you completely flush several times to
> get ALL of the DOT5 out? That is the trouble with DOT5-Silicone
> fluids, it is absolutely not compatible with DOT4. The same will
> have to happen if you switch back.

right, you're supposed to flush with alcohol and plenty of the new stuff.

> The only advantage of DOT5,
> besides the high boiling point is that it is not hydroscopic, and
> does not have to be changed/bled/flushed-- good for collector cars
> that sit forever. (And it does not eat paint). Not otherwise
> recommended by anyone.

it may not be hygroscopic, but that doesn't mean water isn't getting in there anyway.

> Huh? The Pagid pads/rotors should not fade, or change their
> characteristics, until they are gone. You might have air in your
> system or just need fresh fluid. DOT4 should be changed at least
> once a year. By the way, DOT rating is just a US DOT specification
> of minimal dry and wet boiling points-- not a measure of quality nor
> indication of purpose. There are DOT3 racing fluids out there that
> have higher dry boiling points than DOT4/DOT5.1 fluids.

agreed - although right now, i can't think of a DOT 3 brake fluid that has a higher dry boiling point than Motul 600, which is DOT 5.1.

-teddy
------------------

> There are brake fluids made by AP Racing which are DOT3 and are
> equivalent BPtemps of Motul. My point is that the DOT rating means
> nothing, you have to know your fluid. I personally also use Ford.

yes, i understood your point. i just couldn't think of a DOT3 fluid that had a higher boiling point than motul. i believe the AP Racing fluids you mention are DOT 4 fluids. the AP500 is a polyalkylene glycol ether base, and the AP600 is a borate ester base. both require a very thorough flushing before use, since neither is compatible with the more common glycol and polyglycol DOT 3 fluids or polyglycol ester DOT 4 fluids. or are you talking about some AP Racing brake fluid
that i'm not aware of?

by the way, i completely neglected to mention an additional feature of the DOT 5.1 spec: the fluids must be compatible with DOT 3.

-teddy

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[size=+1]Clutch Slave Cylinder[/size]



From: Dave Eaton <dave.eaton-at-minedu.govt.nz>
Subject: replacement of clutch slave cylinder on 016/20vt cars

The following is the procedure for replacing the clutch slave cylinder on a 20vt/016 audi. the procedure is the same with rhd or ldh vehicles, although the rhd cars have separate fluid resevoir on the rhs firewall.

dave '95 sr2 '90 ur-q
------------------------------------------------------------------------------

part numbers: the original slave cylinder for the 10v turbo cars w/016 gearbox is superceded for the 20v (rr) cars to '893 721 261a'. The new cylinder is located in the bell housing by a single bolt, rather than by the peg and spring of the earlier model. This makes removal of the cylinder somewhat easier. More recently, the slave cylinder has been superceded again to a new part number '4a0 721 261'. This looks the same as the old part, but is 2/3rds the price and contains a synthetic (white) operating shaft, rather than the steel one of the older unit. Removal of my old unit showed significant shaft corrosion which is probably the reason for the change.

Symptoms: in my case the major symptom was the excessive use of clutch fluid. As the master cylinder is located in the pedal box on the inside of the bell-housing, it is a easy matter to check where the fluid is leaking. No obvious leaks means that the slave cylinder (which would leak into the bell housing) is the culprit.

Tools: required are 10, 11 and 12mm spanners and a 13mm socket with a long extension and optional flexy joint. also required are a long piece of plastic bleed tube, dot 4 fluid and a cup/container. you'll need a jack and a piece of wood, triangular in shape, 2cm thick, of 6cm tapering to about 3cms. I took a triangular piece of wood and cut the narrow end until it was 3cms across.

Time required: it took me 4.5 hours but, by following these instructions, 2 hours should be more than enough.

Access: a real pita. jack the car, put the front wheels on full right-hand lock, remove the lf wheel and also the shroud around the driveshaft. this gives you the best access, as access from the top is hindered by the abs piping.

Removal: leave the old cylinder connected up and remove the 13mm bolt at the rear of the cylinder. The cylinder is actually located by a burr on the rear of the bolt hole, so the cylinder won't move when the bolt is withdrawn. Ensure that the gearbox is in 2nd or 4th gear, and remove the cylinder by moving it laterally to clear the burr, and then rearwards until it is free from the bell housing. Move the cylinder around to free it from the wiring going to the gearbox sender, and withdraw the cylinder to below the driveshaft. Remove the clutch pipe from the cylinder (12mm spanner) and let the fluid drain into the container/cup.

Replacement: connect the new cylinder to the pipe making sure that the pipe "coil" is located *above* the cylinder. Tighten the pipe enough to stop fluid leakage. With a helper, quickly bleed the cylinder into the container by moving the operating shaft into the cylinder by hand (this gets rid of most of the air in the new cylinder and simplifies the later bleeding procedure). Move the new clyinder into location in the bell housing, and re-route the gearbox wiring as before. It is physically impossible to insert the new cylinder into the bell housing as there is no way to exert enough pressure using your hands. (as the slave cylinder contains a strong return spring, this spring needs to be compressed for the slave cylinder to be inserted into the housing.) The only way i could insert the new cylinder the 2cms or so into the housing was to use the gear selector rods to force the cylinder forward. In order to do this effectively, the use of the wood block is vital. Insert the wood between the selector rod and the cylinder and get a helper to force the gear stick forwards (ie into 4th). Once all the movement has been taken up (the slave cylinder should have moved forwards about 1cm), get them to release the gear stick and increase the purchase of the block between the rod and the cylinder (hence the requirement for wood with a triangular shape). Repeat the procedure until the cylinder is located longitudinally ahead of the burr (to the rear of the locating bolt hole). Push the cylinder rearwards to locate with the burr, and get your helper to release the pressure on the gear stick. Apply the 13mm bolt and tighten. Tighten the clutch pipe after ensuring that the pipe coil is not touching the bell housing. ensure that the ribber piping prior to the coil is not twisted and if so, release the twist by turning the rubber pipe against the metal pipe from the master cylinder at the point of their join. 15mm and 12mm nuts. Bleed the clutch. If the master cylinder has lost fluid, the angle of the cylinder seems to mean that, in practice, it will bleed to the fluid resevoir during inital pedal applications (after the resevoir has been filled). Top up the clutch resevoir (rhd) and road test.
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[size=+1]Pentosin (hydraulic fluid)[/size]
I just received some G 00 200 from the audi dealer and it's green.
Comparing Pentosin 7.1 and G 00 200 next to each other -
G 00 200 is a darker green than 7.1.
G 00 200 bottle specifically says "synthetic" and has a range of
-40f to + 266f. Also says -
"Pentosin Fluid CHF 11S Product code no. 1405108" and
"Made in the U.S.A. Southcoast Terminals Houston, Texas"



Pentosin 7.1 can says -
"Very Important! Pentosin CHF 7.1 should not be mixed with
Pentosin CHF 11S or any other hydraulic oil."
also has temp. range of -40f to +212f .

Looks like all old Pentosin 7.1 is going in the oil change bucket.
It either 11S or G 00 200! Thanks AOA for the info.

***********************************************************************
Steve Hackett sbhack-at-attglobal.net
Huntington, CT

'91 200TQ 20v, 79k
'88 5000s Avant, 66k
'86 5000 CS Turbo, 178k
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[size=+1]Bomb or brake booster[/size]



The hydraulic pressure accumulator (bomb) is made by Lemforder. Their distributor is in Chicago. They are: Northside Imports (either Jack or Rick) at (773) 384-5000.

The following part numbers may be wrong; double check before relying on them.
PN 857-612-061C ---5000-series (thru '88, I believe)
PN 443-612-061H (S4, V8)

Unfortunately, PN 857-612-085A is _not_ available from him. He doesn't get enough orders for this particular bomb bodel.
----------------
(This info is from a procedure on the coupe quattro 20-valve non-turbo; the system is pretty much identical, so I've included it here.)

Most normally aspirated cars have a good supply of manifold vacuum for the power brakes to be "vacuum" assisted (using a brake booster). This means that the heavy brake pedal you feel when the car is turned off is from the engine not producing any vacuum and therefore no vacuum assist to the power brakes.

A turbo charged car runs under positive manifold pressure most of the time so there is not a very good consistent source of vacuum for power assist. The Audi engineers decided to make the power brakes hydraulic assisted, in conjunction with the power steering system. This means that the additional "assist" that power brakes afford is supplied by the hydraulic pump/power steering pump. The hyd. system stores the hyd. pressure in the bomb. This is a cylinder containing a rubber diaphram separating the nitrogen (compressible gas) on one side, from the hydraulic fluid (pretty much not compressible liquid) on the other. The hyd. pump puts out something like 1500psi into the bomb to pressurize the hydrogen gas.

When the bomb goes bad it does not store (accumulate) enough pressure and therefore you will lose power assist (pedal goes hard) upon pumping the brakes. It is thought that the nitrogen gas diffuses through the semi-permeable rubber membrane into the hyd. fluid over time, leaving too small a volume of compressible gas to provide enough assist. Usually the bomb lasts about 7 years.

If your hyd. pump is in good working order then it can supply enough pressure for light braking but under emergency braking (or braking after your engine stalls) you might lose the power assist.

Some normally aspirated cars have hyd. assist and a bomb also (mid 80's BMW 5 series for one). Some turbo cars have vacuuum assist. Some cars also use a bomb for hydraulic or self-leveling suspensions. The unit has been given the nickname of "bomb" because of the shape of older versions -- rather like a cartoon bomb seen on the Rocky and Bullwinkle Show.

The standard tests:

* If the brake light (the warning light on the dash that also comes on when the parking brake is up) stays on for several seconds after starting the car, suspect the bomb.

* After driving, shut down engine and pump brake pedal until it loses power assist (gets stiff). If it takes less than 10 presses of the pedal, you could have a bad bomb.

* Press brake pedal as hard as possible while engine is running and car is stationary or moving slowly. If brake light comes on and the pedal initially feels like it has no assist, the bomb may not be holding pressure.

A thorough test:

1. Engine running at idle, steering to right or left full lock 20 seconds, at the same time pump brakes hard 10 to 15 consecutive times. Does the brake light come on? Yes = bad belt, pump, or bomb (check valve). Pressure bleed before exchange!

2. If the light doesn't come on: stop engine, pump brake 10 to 15 times (short quick strokes). Brake light on? Yes = bad bomb (pressure accumulator).

3. If light doesn't come on: Drive the car in a very safe place at 65 mph then apply full stop pressure to brakes (emergency stop pressure!). Does ABS actuate several times? Yes = good bomb! Brake light on? Yes = probably bad ABS sensor. Above assumes booster cylinder has been tested for leaks ! They don't seem to hold the N2 charge for more than 6-7 years (diffusion of the gas through the membranes).

Just to eliminate the possibility that it's the booster itself, unscrew the return hose from the booster (the thin one, that goes to the reservoir). Do this with the engine OFF naturally! If the booster continuously drips the snake fluid out of that hole then its internal check valve is no more (12 droplets is OK though).

Replacement: Make sure you get 2 copper washers for banjo bolt of the high pressure line from the hydraulic pump to the bomb. I recommend you use this opportunity to replace the hydraulic fluid (Pentosin) for the brake booster and the steering rack. During the bomb replacement, you will have to disconnect the hose leading from the reservoir to the pressure accumulator (bomb). At this time you can drain the Pentosin, assuming it has not been replaced recently.

1. Decide first whether you will reuse the "pentosin" (hydraulic fluid) or replace. If you want to reuse, have available a very clean 1 quart container, or one not as clean if you intend to replace.

2. After car is in position, pump the brake pedal (with engine off) 30 to 40 times to relieve pressure from the "bomb". Don't neglect this step; the Bomb will act just like one if it is disconnected without first removing the residual pressure. No joke, mechanics have lost fingers doing this! It should be perfectly safe once the pressure is removed.

3. Disconnect the hose from the hydraulic reservoir to the "bomb" (hose clamp), remove the hose by rotating (twisting by hand) and quickly insert it into your recovery reservoir. Allow the system to drain entirely.

4. Loosen the 17mm banjo bolt from the high pressure hose (from the hydraulic pump) and remove by hand retrieving the two copper or soft material washers ( both need to be replaced) located above and under the hose connection. There should be minimal fluid presence at this time.

5. Loosen the 11mm connector of line from the "bomb" to the booster cylinder at the "bomb" side.

6. Loosen the nut at the front side of the "bomb" and carefully lift the bomb up and diagonally towards the passenger side. This will allow the front screw to move free from the short slot in the retaining bracket.

7. Allow the bomb to drop a little and twist it (rotate)in both directions while pulling towards the front of the vehicle, until the back rubber bushing becomes free from the back hanging bracket. The bomb is now free.

8. Install the new "bomb", tighten the forward retaining nut, attach the line to the booster cylinder and high pressure hose ( 2 new copper washers ), reattach the hose to the hydraulic fluid container, and refill. It will take some time for the pump to refill the bomb to proper pressure, usually a good 5 minutes or so.

Hydraulic Servo
There is a relatively easy test for hydraulic servo (booster amplifier ???) leakage: After running the engine at about 2000 RPM's for a few seconds, stop the engine. Carefully disconnect the metallic return line from the servo to the Pentosin reservoir (have rag handy) and observe for a couple of minutes. Only a few drops of Pentosin should come out from the servo. If a more definite flow is present, the servo is leaking. If the servo leaks during this test, there is a high probability that the pressure accumulator is O.K.


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[size=+1]ABS (anti-lock braking system)[/size]




ABS sensor depth adjustment caps were used on the earlier cars (illustration 155-60 is a bit smudged on my fiche copy (aren't they
all?), but i would guess the part number is 437 927 809....the "8" is the questionable digit...). Our cars use sensors that press in to a stop using reusable collets.

ABS wheels speed sensors are about $48.56 (each) list. Part number 441-919-351-A.

If a sensor is bad, the light will stay off when the car is started, and then come on after driving the car from 10 feet to 2 miles. If the problem is elsewhere, it may turn the light on before moving the car.

To find the bad sensor, listen carefully after starting your car for unusual noises from one wheel. That's the one with the bad sensor. The noise is the ABS kicking in and out, until it decides to shut down. You can hook up a DMM to the sensor outputs, raise the car and spin the wheel. You get a square wave (A/C) from the sensor. The actual value is irrelevant, matching them is. Basically, you want to get the same reading from all sensors spinning the wheel approximately the same speed by hand. Try removing the sensor, cleaning it, and reinstalling it until it rubs the hub. DON'T drive it like this you may damage it!! You must back it out slightly. It should not rub, but be very close. They should "bottom out" while installing, without hitting the sensors on the driveshaft. The sensors too far from the driveshaft will give you pedal "boing" -- this is a groaning/spring sound just as you come up to a stop. The sensors too close will give instant ABS pedal kick in. Too far out tends to shut off ABS quicker than too close.

If you can't get the light to go out at all, you might have a fault in the center differential lock switch, or one of the sensors is just bad. Worn or crudded driveshaft splines can do it too. There is an inspection/water drain at the bottom of each strut, you can sometimes get a brass bottle brush in there, though pulling the driveshaft out is easier, and about a 20 minute job. First check for proper sensor output, then check the differential switch, then the driveshafts. Rarely does that ABS box go bad. Sensors out of alignment usually allow the light to come on till the first brake app or 20-30 seconds, whichever comes first.

There have also been reports that a worn wheel bearing can also cause ABS problems.


<HR width="100%" SIZE=6>Извините за ингиш

 

Ответ: Важно: всем у кого проблемы с тормазами

А это ты к чему запостил?

 

Ответ: Важно: всем у кого проблемы с тормазами

правительственный заговор? Инопланетяне среди нас? Марс атакует?

 

Ответ: Важно: всем у кого проблемы с тормазами

RussianMan Чтобы проточить диски или что-то подобное без биения или устранить последнее, на мой взгляд, не нужна научная степень. А нужен нормальный (даже не хороший, а просто нормальный) токарь и нормальный токарный станок! Утверждаю это вполне авторитетно, так как работаю в ремонтном цехе ремонтного предприятия, обслуживающего целое объединение.

 

Ответ: Важно: всем у кого проблемы с тормазами

Могу добавить, что ученая степень довольно часто мешает
быстрой и здраво качественной проточке дисков... :cry2:

Не относится к теме аффтора конечно, просто заметка

Между прочим отличные результы при минимуме затрат дает проточка дисков не снимая, с помощью стенда - резцовые головки с автоподачей крепятся на место суппорта.