Ur quattro rr

[mac2226]

Any help from ur Quattro owners been bleeding the brakes manually from back to front longest away to shortest away it has big reds on front got the bubbles out till it was clear and clean brake fluid coming out the brake pedal feels good after bleeding but it vibrates once you apply brakes while driving it and exclamation mark comes on dash and there's no leaks under car what's causing the vibrations abs sensors are fine

[AndyP]

Does the vibration feel like the ABS triggering or a warped disc?

[mac2226]

Hi Andy Discs are fine I think but would need double check again if there blue as this could be a sign of warped discs and I've not driven it yet so can't say Andy sorry,only been told by Steve brown but once I bleed it again and test it I will know but yes I had a abs sensor fault on my s2 aby similar problem how Steve told me just have to double check everything thanks

[AndyP]

If you've been working on the brakes, I'd pull out all the ABS sensors and check there's nothing stuck to the end of them. They're magnetic and if any bits of rust or debris stick to the end it will cause triggering problems.

[steverrquattro]

If you've been working on the brakes, I'd pull out all the ABS sensors and check there's nothing stuck to the end of them. They're magnetic and if any bits of rust or debris stick to the end it will cause triggering problems.

I'd already had the rear ABS sensors out Andy and one had some sh*te stuck to it. Will do the fronts tomorrow.

The pedal feels good when the engine is turned off, but when running, the pedal goes slowly to the floor with a vibration and if pushed quickly, the brake warning light will emit for an instant.

I've pressure bled again and put a litre through each rear caliper this evening and still no good!

[newsh]

I'm afraid this may be the Servo going bad Steve

[Tonybolony]

If the problem was ABS related, try driving with Difflocks engaged- this switches ABS off (Unless yours has ABS switch on dashboard, from memory it was by drivers' left knee on mine,in which case try that).

I've just remembered as well that I changed the Brake Master Cylinder because of probs with mine- not a difficult or expensive job. The BMC came from Pete Reeve, and it arrived the following day.

[steverrquattro]

If the problem was ABS related, try driving with Difflocks engaged- this switches ABS off (Unless yours has ABS switch on dashboard, from memory it was by drivers' left knee on mine,in which case try that).

I've just remembered as well that I changed the Brake Master Cylinder because of probs with mine- not a difficult or expensive job. The BMC came from Pete Reeve, and it arrived the following day.

Just changed the BMC as the front brakes were binding on, hence the brake bleeding.

Going to have another go tomorrow with the foot pedal.

[steverrquattro]

I'm afraid this may be the Servo going bad Steve

How can you reliably test the Brake Servo?

The favorite at the moment seems to be the Brake Accumulator, but before I go for it I want to check the Brake Servo.

[AndyP]

How can you reliably test the Brake Servo?

The favorite at the moment seems to be the Brake Accumulator, but before I go for it I want to check the Brake Servo.

I have the accumulator off my 3B if you want to borrow it for testing?

[audiurq]

Not trying to be cheeky but did you bleed both sides on the big reds... If you only
did the outer you would get pretty harsh vibration...

cheers, Mike

[steverrquattro]

Not trying to be cheeky but did you bleed both sides on the big reds... If you only
did the outer you would get pretty harsh vibration...

cheers, Mike

Yes I did.

I'm going to remove the return hose from the Brake Servo today as this seems to be the best way of checking. If little or no fluid comes out, then it should mean that it is the Brake Accumulator.

Got this from S2central's site:

Testing the brake servo for leaks -

Keeping the engine off, disconnect the hydraulic RETURN pipe on the brake servo. A few drops of hydraulic fluid should escape. If a continuous flow is observed, the brake servo is faulty and must be renewed and reconnected to the hydraulic system.

http://s2central.net/main_frame.html

[steverrquattro]

I've removed the return pipe from the Brake Servo and there were lots of droplets of PAS fluid. So much so, that after 1 minute, it was still gushing out so I just refitted the union.

Putting on a brave face, I have contacted GSF who told me it is not available. Not to worry I thought to myself as Pete reeve will have one of these and guess what........he hasn't, nor has he ever supplied one.

I talked to him about all the threads on here and that people had replaced them, so my question is, where do I get one from?

Is there a seal kit available?

Is this the correct part number 857612107C ?

[Pete Reeve]

Hi steve the correct part number is 859 612 107 for the RR quattro

[steverrquattro]

I've removed the return pipe from the Brake Servo and there were lots of droplets of PAS fluid. So much so, that after 1 minute, it was still gushing out so I just refitted the union.

Putting on a brave face, I have contacted GSF who told me it is not available. Not to worry I thought to myself as Pete reeve will have one of these and guess what........he hasn't, nor has he ever supplied one.

I talked to him about all the threads on here and that people had replaced them, so my question is, where do I get one from?

Is there a seal kit available?

Is this the correct part number 857612107C ?

I think I've done this wrong. Having just repeated it now and for clarity, no droplets came out of the Brake Servo and the fluid just stayed level at the top of the hole from where I took the return pipe out.

However, it was the return pipe from which the droplets came and NOT the Brake Servo.

Can I assume that with a faulty Brake Servo, you are looking for any PAS fluid to come from the hole where the return pipe fits in the Brake Master cylinder?