rear brakes binding - Page 2

A8 Owner · #11 30th August 2013, 10:32 PM

thats the thing it had only failed MOT on the 2 things track rod ends and airbag light. So just went in for them. As MOT tester said brakes passed last week and drove it fine on tuesday to them. He even said it drove fine into workshop. Only thing the car elec bloke did different to air bag fix was put two resister's in,as i think he said other wise seatbelt would of had to be plugged in all the time. Im just wondering if there was anything he could of done, when fixing this has caused this problem.

Architex_mA8tey · #12 30th August 2013, 10:51 PM

D2's are a bit notorious for the handbrake sticking on via the rear brakes so I would certainly try to be very sure it's not that, it's some times easier to take the rear caliper off and work the adjuster. It does seem odd that they are both sticking on though,that's for sure, it's normally the offside rear that sticks with handbrake issues

ainarssems · #13 31st August 2013, 01:54 AM

It's most likely to be the fault within calipers either pistons sticking, floating guide pins sticking or handbrake shaft sticking or could be handbrake cales sticking.

I really doubt it's ABS pump at fault. If it was pump you would definitely hear it working as they are quite loud when in operation. Also no need to undo bleeding nipples to check it, that's just unnecessary work and waste of time, much simpler just to pull the fuse for ABS pump or unplug the pump.

ainarssems · #14 31st August 2013, 02:21 AM

Now thinking further about it the way ABS work is is if a wheel is about to lock up the valve opens and releases the pressure from the corresponding line, then closes and pump brings the pressure back up. If the brake pedal is released all the brake fluid would just go back to fluid reservoir through the main brake cylinder without pressurizing even if pump was running constantly.

And it cannot be main brake cylinder at fault as well as it has 2 diagonal circuits so if that was sticking if would affect one front and one rear wheel not both rear wheels.

It's got to be mechanical issue within calipers or handbrake cables.

A8 Owner · #15 31st August 2013, 09:42 AM

Quote:

Originally Posted by ainarssems

And it cannot be main brake cylinder at fault as well as it has 2 diagonal circuits so if that was sticking if would affect one front and one rear wheel not both rear wheels.

It's got to be mechanical issue within calipers or handbrake cables.

Well went there first thing and found it was diagonal not both rears like i thought they said on phone. Well they took the preassure off lines, the wheels span around.

Now got to search, to see how much a recon one is, compared to a A8 parts one. Cheap MOT now turns into a big bill.

A8 Owner · #16 31st August 2013, 08:45 PM

Can anyone tell me are there any sensors nr or on track rod end?

Asking as someone on another audi had a track rod end changed and had same sort of problem. traction control or steering angle sensor. Would a ABS sensor cause this?

Any chance these are on a A8?

ainarssems · #17 31st August 2013, 10:19 PM

There is a steering angle sensor but it is in steering column not on the track rod ends. After changing track rod ends wheel alignment should be done and after that steering wheel angle sensor adaption/calibration should be done. But even if it was not done it should not cause the issue you are having.

Simple test would be to pull the ABS/ESP fuse, that would disable system altogether and remove any issues that are caused by it.

It looks like one of the pistons in the main brake cylinder is stuck and not returning.

I am not a professional and I could be wrong.