Brake troubleshooting advice needed

[fendervg 29]

Still struggling to get satisfactory performance after a 288mm/Mk4 brake upgrade on my VR about 3 months ago. The pedal travel is quite long, and I don't see a marked improvement in the braking.

 

How much better than stock is this mod supposed to feel ? How does it compare to say, an Mk5 1.6 Golf's braking ?

 

At this stage I've done the following:

 

- braided hoses

- new disks and pads fitted at time of change (ATE)

- fluid change

- system has been professionally pressure bled 4 times so far, with only slight improvements

- bled ABS pump and master twice

- cracked open the ABS pipes slightly - some air in there

 

What's next ?

 

- clutch ?

- replace disks with VAG items and DS2500 pads ?

- bleed whole system again myself ?

 

Any other ideas ? All thoughts are welcome as it's driving me cracked and very disappointing after such an expensive mod.

 

Many thanks.

[16VG60 0]

The problem you are having is very common with the ABS system on the VR6. It is not uncommon at all to find that the brake pedal feel is poor post works involving opening the hydraulic system. If you are sure in the fact that you have thoroughly, and correctly, bled the system with fresh fluid. Then providing there are no actual faults with the system operation other than pedal long travel, you will find that driving the vehicle with the appropriate caution for a week should see the return of normal function. Clearly if the brake system will not render an acceptable brake pedal reponse then driving is out of the question, but the pedal will often have long travel with a good operation.

 

 

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[fendervg 29]

Well, it's not so bad that it's undrivable, and it feels perfectly safe - it's just that there does not seem to be any perceptible improvement over the old setup. Thanks for your input though.

[VW_OwneR_85 1]

sounds to me like you just need to let the discs and pads wear in to each other, when there new they dont sit 100% square with each other untill there wear abit,

[paddy26 3]

I drive a mk4 golf and when I have to drive my sisters mk5 I nearly go through the windscreen when I first press the brake pedal. As the others have said let them bed in before you spend more money on it.

 

Paddy

[fendervg 29]

It's been bled 3 times by an independent specialist who fitted the parts, and once by a VAG main dealer - covered about 2000 miles since then, so I'd expect the pads/discs to be well bedded in at this stage.

[mimjed 0]

indeed, should be bedded in after around 500 miles.

 

possibly damaged the master cylinder whilst bleeding??

 

is the pedal spongy? or just very long travel?

 

think the test was hold the brake in as far as it will go and then turn the engine on and see if it goes further down.

[RW1 0]

Long travel (down to halfway) usually suggest that one circuit of the brakes has failed. ie. the master cylinder. If it was pedal pumped rather than vacuum/pressure fed during bleeding to remove the old fluid, then the old rubber seals of a master cylinder can heat up and fail.

 

Braking will still be even-ish as thats what its design to do but performance will be down.

 

.

[fendervg 29]

Is there any way to identify the circuit failure ? Just my luck as I believe the brake master is now NLA lol: :(

[mimjed 0]

if it is the master and its obsolete at vw, im sure i could get hold of an oe spec one for you. just give me a shout if needs be.

[fendervg 29]

@mimjed: would that be an ATE one ?

[dukest 0]

you really cant compare our brakes, 288s or otherwise, to anything less than about 8 years old, the pedal just wont ever be the same. there is a definite and noticeable difference to standard though. was there much of a gap between you driving it between old and new?

[16VG60 0]

If you require an ATE master cylinder I have one advertised on this forum which will fit your Corrado. But first make sure this is what you require, no point in panic purchase to compound your woes!

 

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[fendervg 29]

Granted the performance will never match up to more recent car - the servo assist is much more powerful. However, I had an experienced VAG modifier drive the car recently and he thought they were standard brakes ! I know the rears will not make much of a difference, but the fronts should, as they do all the work.

 

@RW1 - what would the troubleshooting procedure be for circuit failure ? I presume it is a diagonal circuit.

 

@16VG60 - would that be an ATE master ?

 

Maybe I should just get another Irish forum member to dirve it. I drove straight away after the work, and I use it almost daily.

[Dox 22]

I've had similar probs with an audi cab that been sorn for a few years - the pedal went to the floor, new master and bled by the garage made no improvement, I bled them several times using the 2 man method, I then bought one of these

 

http://cgi.ebay.co.uk/SEALEY-Brake-Clutch-Bleeder-Bleeding-System-Kit-VS820-/140531959466?pt=UK_Air_Tools_and_Compressors&hash=item20b85b86aa

 

A cracking bit of kit, I was also advised to wedge the pedal down over night - this pressurises any air bubbles in the system and they split into smaller bubbles and are easier to get out. I bled all 4 corners ( make sure the rear brake compensation valve on the rear axle is fully open if fitted), then opened various pipe connections to see if any air is trapped.

 

I used the car yesterday and the pedal is improving all the time

[mimjed 0]

Not sure chap pm me your numberplate and ill find out and get a price on it. I get trade price so shouldnt be too steep.

[mimjed 0]

can you confirm the part number from yours? im coming up with 357 611 019 b

 

but it doesnt list it as abs or non abs, so just want to be sure.

 

it is an ate one, brand new, looking at £70 inc VAT. but would be plus post to ireland.

[RW1 0]

can you confirm the part number from yours? im coming up with 357 611 019 b.

You want 358 611 019D for RHDrive Chassis MK014975 onwards. "7" is LH Drive Passat.

(Originally fitted it was 358 611 019B)

 

.

[16VG60 0]

Fendervg, yes it is an ATE genuine parts master cylinder with brake fluid reservoir included.

 

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[fendervg 29]

Cheers for checking that - still puzzled as to how you would tell if a circuit had failed - the Bentley has nothing on it, not even a diagram of the layout.

 

@mimjed: can you check a price on the later one, and I'll also check with an ATE dealer here, to see if it works out cheaper without the postage ?

[mimjed 0]

Yes chap, will get back to you.

[fendervg 29]

Anyone with advice on how to check if a brake circuit has failed ? I would have thought that this would have been picked up during bleeding.

 

Thin I'll get one of those Sealey jobbies - looks a lot better than an eazi-bleed.