VW Touran diesel master cylinder?

Have you spoken to whoever did the work? Perhaps it still has some air in the system?

WRT cost, Autodata gives a replace time of 1.6 hours, so it's not a very expensive job.

Chris

They will sink anyway because diesels don't use manifold vacuum.

But if its now noticeable I concur that its most likely not bleed correctly. Should not require a new M/cyl just because you had the system fluid changed.

Only when the engine's running. I believe the pedal shouldn't sink with the engine off.

Well if they've pumped the pedal to the floor past its normal "working" range of movement I believe it can bugger the seals on an older master cylinder. Dunno whether the garage will admit that though. :-(

Tim

Doesn't feel like that. Pedal doesn't "pump up" in the same way but slowly sinks under sustained pressure.

Well that's encouraging at least.

Thanks.

Tim

Yes, it can, but most reputable garages will use either a pressure or a vacuum bleeder.

I've got a rough idea...

Chris

and if they used too much pressure, the seals could be turned inside out?

the pressure bleeders are fixed at a very low pressure anyway, and to turn the seals would need a pre existing fault: the fluid can just flow through without affecting the seals if the master cylinder is fully 'off' and there are no faults. If they bled it by pumping the pedal then it is quite possible to damage the seals against a rusty area of the cylinder. I have done this myself years ago, and once had it happen on an MoT when a really hard press of the pedal damaged the seals.

Hmm, latest update from garage is that brakes won't bleed on one side of the car and they're a bit confused. Wondering if it's to do with ABS system. More investigation required.

Could it still be "just" the master cylinder or does this suggest another problem as they suspect?

Too fecking compilcated cars these days...

Tim

unless they are a specialist VW place then they may not know what they are doing:

from the web: "anyway back on the touran problem yes it is a common fault and if the ABS light comes on then the vehicle is still safe to drive but it is highly advised that it is taken straight to the nearest VW dealer who can quickly and properly fix that problem by replacing the pump.and these have to be bled properly using the VAG5051 diagnostics machine as it has to run a sequence to ensure all the air is out of the pump and braking system"

Note the last bit. Sorry.

I did take it to the main agent as my local garage couldn't look at it until Thursday. They *ought* to know what they're doing. There are no warning lights, ABS or otherwise.

Tim

Certain ABS ECUs of this age have a known issue, but that usually shows a warning lamp, and not really related to your issue but relevant to Mrc's quote above.