Sir Chucksalot

I don't really know how to test this until it snows, but I think my rear brakes are doing a larger amount of braking than is intended (and the fronts are doing much less than they should). I am at a loss as to why (or how) this could be. I have a 95 90q sport

My reasoning is as follows:

1. When cleaning the car, there is a lot of brake dust on the rear wheels and little to none on the front.

2. I have warped two sets of rear rotors in the past year and have had to replace my rear brake pads before the fronts.

3. With the warped rear rotors I can feel the car lurch with the rotation of the wheels as it comes to a stop (slow speeds).

Can anyone enlighten me as to what the problem might be? I'm kinda tired of going through rotors at this point and am worried about wet/snowy handling.

Thanks,

Chuck

1993audi90

Interesting. I'm working on a 95 Q now. I have had a # of FWD B4s in the past and was amazed this weekend to not see the proportioning contraption in the rear of the Q. Apparently, the proportioning valve on the 95 Qs is out front. If I were you, I'd put a Motive Power bleeder on it and see what comes out at the calipers. If I saw a nice even flow at all 4 calipers, I'd look at the brand/type of pads I was using on the rear--and make sure the E-brake is adjusted properly.

elaw

There are a number of things that could be going on. As the previous poster mentioned, the e-brake could be misadjusted. Or, when you release the e-brake lever, due to bad cables or calipers it might not be releasing completely. One or both rear calipers might be sticking, causing the brakes not to release properly.

Try putting the car on a level surface, and (carefully!) leave it in neutral with the e-brake off and jack up each corner. Spin the wheels by hand and see if the rears seem harder to spin than the front. If so, the problem might be one (or several) of the things I mention above. If the rears spin as easily as the fronts, maybe it's a difference between pads F and R?

Sir Chucksalot

Thanks for the help guys, I'll check it out next weekend when I am home for the holidays (and have a flat (warm) garage to work in). There might be a chance that my rear calipers are failing, but I haven't noticed any decreased gas mileage (which I would assume would come with brakes rubbing/calipers failing). I guess we'll see here in a couple weeks.

kakarot1232001

I had a pin in rear caliper jam once, MPG did not decrease, but did eat through inner pad really fast.

If you have time, bleed the brakes, relube the pins, and check that pistons are moving freely.

You will need special brake tool that can be borrowed from pepboys/autozone to push rear pistons back in.

Audi0s

I think if the rears were doing the most braking, theyd be locking up on you under heavy braking since there would be no weight back there. Or ABS would be on. What condition are the wheels in? Ive seen some dust up when the clearcoat goes and the dust will stick better. If the ebrake feel like it has no resistance for the first few clicks, then picks up the cable, its possible the cables are frozen. If the calipers seized, usually the rotor will turn bright orange/red rusty from heat, an easy way to spot if somethings going on.

egp320i

Remove the caliper and check your guide pins on the carrier. They are notorious for becoming dry and sticking especially the bottom which sees more road wash.

Pull the pins out and re-lube and make sure they rotate freely once inserted.

I find myself doing this once a year to make sure they move ever since I had a pin on my right side become frozen solid forcing me to buy a new carrier.

It does sound like your pads are riding on the rotor.

Do you have the same brand of pads front and back? Some pads are naturally dusty and some are not.

I used PBR metal masters for years but have since switched to EBC ultimax pads which are much much better and also cost less.

Pagid,Mintex and Textar are dusty, two other popular brands.

hubturn

Not a quattro guy, but what about the master cylinder? As previously mentioned, I'd check fluid flow first to establish that the master cylinder is pushing fluid to the fronts. Isn't the master cylinder split for both fronts and both rears so as to have even braking (either front or rear) should there be a failure? The complaint of no dust at the front is troubling.

Sir Chucksalot

Hmmm... I'll have to check the condition of the pins this weekend in my local Kroger parking lot (ah the pain of not having a driveway). What do you suggest I use to lube these back up... all I have in my apartment right now is bicycle chain lube.

The pads are different in the rears as I just replaced them (no idea what they were originally), so it is possible that they are just more dusty - hadn't thought about that.

egp320i

Yes it splits. The front wheels each have their own line and one line runs down the center of the body and then T's off with a proportional valve to the rear wheels.

One way to check the fronts is to simply remove the caliper, string it up and push on the pedal to see if the piston moves out. A pair of C clamp vise grips works great to push the piston back in if you don't have the actual tool.