Aaaaaargh No Brakes =(

[muffin]

hi all,

2001 (51) A4 2.0 se triptronic, brake problem

sometimes whilst driving the brake pedal becomes really stiff and theres no braking whatsoever. this would happen for maybes 4secs and then braking is restored. sometimes the pedal is fine sometimes its stiff as hell

brakes feel as if theres no vaccum, then when pressure is applied to pedal the vaccum kicks in.

paid a visit to the local mechanic but he's booked it in for monday to have a proper look at it.

looking up on the net iv found the 'brake booster' could be at fault?? is it more likely to be the servo?

anybody able to shed some light on this matter??

[Bugbear]

Could be either but the first check is simple.
Put your foot on the brake pedal and start the engine. If the servo is working the pedal should go down as the engine starts.

[bora(ing) nick]

I'm sure i've heard it's common for the brake servo to cease internally on these, due to water from the windscreen getting in and corroding the internals...

Hope you solve it soon, its no fun when brakes fail.

Nick

[muffin]

thanks for the quick replies

bugbear - pedal does go down as you strat engine assume servo is working

nick - is there any way to check the servo without taking the engine apart?

where is the servo located?

anyone know where the brake booster is located?

one thing i have noticed is when the brakes 'fail' if i yank the handbrake up the brakes come back in action.

[muffin]

quick update!

turned out the breather pipe had a split in it and the vacuum pipe which runs near the breather needed replacing, cost about £50 all in.

problem sorted!

[mrtenpercent]

Hi Muffin

I have a 2.0 SE Multitronic '51 and had a very similar problem today! Pulling up to lights and no brakes! But intermittent afterwards.

Whereabouts is the breather pipe located? Is it on top of the engine, on mine there is a pipe which appears to be sucked flat by the internal vacuum and when I open it up I can hear a hissing noise. Is this similar to yours and does anybody else have any ideas?


Cheers

[muffin]

hi mrtenpercent,

i too had the hissing noise when i opened the bonnet. the breather pipe is located towards the top right of the engine block, its a small thick black 'pipe' which has three branches (looks a bit like an E, it seems to be a point where three metal vacuum pipes meet and has got a few bends in it). i imgine it is the pipe your referring to as being 'sucked', if it has a split in it i think it will definetly become sucked flat. mine didnt become flat and however its also worth checking the vaccum pipe which runs very close to it.

is your engine sounding a little rough? if i recall correctly mine was rough and after replacing the breater and vaccuum pipe it was all sorted. basically the breather pipe will make the engine sound rough as theres not enough 'vacuum pressure' at the engine.

if your still stuck i can e-mail you a pic with its exact location, jus pm me!

[chucky]

Hi there
I had an intermittant brake problem which was exactly like you described,rock hard pedal and no servo.
used to drive okay for a fortnight then surprise you when you least expected it.
the mechanic went through everything in stages until he changed the servo,which was damaged due to water from the windscreen filling the battery tray.
the drain holes were blocked.
the part you had changed if I remember correctly is the bit that they first changed on my car.
it took 4 months and a few more bits before they got to the servo!!

hope this helps
chucky

[mrtenpercent]

Cheers Muffin

Thats the pipe thats getting deformed by the sound of it. theres a couple of other pipes local to it that are showing some wear so they will all get replaced at the same time and see if that fixes it. And yes the engine does sound a but rough (but then I think it always has).

Chucky, thanks for the reply, if the pipe replacement doesnt work I will definitely look at the servo. Mine is intermittent but not over that long a period., over a three mile journey after the problem started it worked fine about half the time, the rest of the time it was servoless.

Its good to get some good feedback about this, so thank you for the time you have taken to respond.

I will let you know how I get on.

Thanks again


Mr 10%

[graham lawlor]

I HAVE A SIMILAR PROBLEM.ALLWAY'S SEEMS TO START AFTER A FROST.INTERESTED IN THE WINDSCREEN WASHER WATER AFFECTING THE SERVO.BRAKE PEDAL ONLY STIFF WHEN ENGINE OFF.SERVO SEEMS TO WORK WHEN ENGINE STARTS AS THE PEDAL DROPS TO NORMAL POSITION.SEEMS TO BE COMMON PROBLEM WITH DIFFERENT SYMPTOMS