My 2003 Octy RS had it's 60k service last week including the brake fluid change, now if you apply the brakes hard the system remains pressurised and all the the discs bind to the point where the car hardly moves unless you give it some welly, the only way to free them of again is to crack the bleed nipples on the calipers.

Having spoken to a couple of Audi techs and they say that some of the VAG cars need to be pressure bled and can't be done in the convensional way (furthest first), does anyone have any idea if this is the case or have maybe the seals in the master cylinder turned on themselves?

Andy.

I'd suspect your master cylinder seals. If it has been bleed using the old foot on brake bleading method chances are the master cylinder has traveled in an area it normally doesn't and this can damage the cylinder. Or if pressure bleed the pressure has been to high (shouldn't use more than 12 PSI). Most people use an easy bleed pressurised system (gunson) or similar. They can also be vacumm bleed at the deelers which is done when air gets into the ABS unit.

The furthest should ALWAYS be bleed first so dont know what the audi techs are saying there.

Basically 3 type of bleeding

1. manual pedal bleeding

2. Pressure

3. vacumm

All should be done in the order

1. Rear passenger

2. rear drivers

3. Front Passenger

4. Front drivers

5. 2 bleed nipple of master cylinder.

Dont know about left hand drive but this is the case on RHD models.

So who did it? I'd take it back to them if they are at all competant.

I've seen both the pressure bleeding comment, and the one that some VAG cars with ABS require an unconventional bleeding sequence before.

I'd agree about taking it back to the place that did it (even if it was Kwik Chimp, you still need to give them a chance to sort it unless you want to pay twice).

My Haynes manual suggests different bleeding orders depening on the type of ABS unit fitted to the car.

Went to my local Skoda dealer yesterday to get the relevent information about bleeding the brakes, and all they ever use is pressure bleeding which doesn't involve using the pedal at all.

They seem to think the same as me, that the rod in the cylinder has moved past it's normal operating wear points and the seals can't return (they do when left overnight).

I took the car back to the workshop that did it with the instructions to get it sorted (new master cylinder) today.

Got the car back today and fully sorted:),

problem was nothing to do with the master cylinder as the problem was still there after it was replaced:thumbdwn:.

Turned out to be the servo, the locking ring that holds the servo rod (that pushes the master cyl rod forward) in place has split and deformed moving everything in the servo out of line.

When the brake pedal was pushed the rod moved past the 1st ring of the spring in the servo and because of the angle it couldn't return, but overnight the spring tension would pull it back and release the the brake pressure.

Andy

P.S did you know that according to the box the master cylinder comes in the Octy VRS has the same as the Ferrari F40!

Cheers for that; it's another of the "unusual ones to chalk up to experience".