Audi A4 brake problem

If you don't have a clue, why leave it to your wife! Why not phone the dealer or call in yourself. Also why question the dealer? I think they are far more qualified than most hobbyists in a newsgroup. The diagnosis is correct so discuss it with them - they will explain all the technical details to you.

Oh do shut up you tedious prat.

clive

(hi mark :-) )

I'm going to do exactly that tomorrow but I'd like to understand the possibly causes first.

I'm sure they are - but I've had some bad experiences with the the motor trade. The last garage who serviced a car for me assured me that they couldn't change the brake pads because a pin had seized and so it needed a new caliper. All very plausible but there weren't any pins in the caliper and I changed the pads without any problem.

Hmmm, not the most helpful post ever.

Er hi Clive - didn't expect to find you here. Too many wheels surely...

Bad form n'all, but it just occurred to me : Yup, Tiscali Idiot.

clive

Still get to spanner the BX sometimes :-)

(and I got the answer here to my last problem (alternator) - the BX list has all but died.)

cheers, clive

I can't see either of those components giving this symptom, it sounds like they want to replace everything until it's fixed. ie, they haven't got a clue. I suspect something seized, has the A4 got a crosslink from the pedal to the M/cyl? I've known those to seize, but it would be rare on a car this young.

Steve

A faulty vacuum pump wouldn't cause the pedal to stick.

Given that the pedal is physically sticking down, then it's either a seized pivot somewhere, the master cylinder, or the servo.

I'll second that. It's very unlikely indeed, if not impossible to be the pump.

let the dealer both diagnose and do the work. If it doesn't cure it then get your money back!

I think everyone has repaired 'what they thought it was' and found the real problem along the way. So paying the garage will probably get the desired result, but not necessarily by the most economic route.

My idea is that the dealer can't see how either - but the usual method is to replace associated parts until the problem is fixed. The vacuum pump is probably easier to replace than the servo, otherwise they'd be doing it the other way round.

I'd have thought bleeding the brakes would be the cheapest thing to try first!

Agreed. I had a similiar problem with my VW Transporter. After I flushed and bled the brakes, they would drag after heavy braking (until I stopped and allowed then to cool). But the pedal felt higher than normal too.

I bled the brakes again, this time making sure that the pedal got released slowly as the bleeding progressed (the wife was working the pedal). I don't know if there's something special about releasing the pedal slowly, but the workshop manual for my Nissan makes a strong point about doing it that way.

That second bleeding fixed the problem.

John

releasing the pedal slowly reduces the chance of it sucking back fluid or air and allows the reservoir time to top up the actual cylinder, a few second pause at the top is a good idea too.

the op problem sounds like either a stiff linkage or a faulty master cylinder with a slim chance of a servo fault (not returning) older servos had a variable length push rod which if mal adjusted could hold the brakes on, I do not know if the op car has that.

Mrcheerful