MK4 Golf Master Cylinder

[damianzmd]

Recently I had my rear brake pads replaced, at the same time, the brakes were bled. After they were bled (or attempted to) the pedal goes all the way to the floor with the engine on.

My guess is the Master Cylinder has completely gone. Was wondering if anyone has had similar experiences? I'm going to buy myself a new master cylinder and replace it.

My mechanic says that the seals in the master cylinder may be worn/broken. But why would this happen all of a sudden as soon as the pads were put on, when they were working fine before?

Also, when I push the pedal in, its extremely soft, goes right to the floor, and you can hear a .. err, 'farting' noise from in and around the master cylinder reservoir area as I push it in.



Thanks in advance.

[balkanac]

check that the bleeding screws are tight on the master cyl and all wheels and check the hoses. Its sucking air from somewhere. Its strange that the master cyl would fail after changing the pads and bleeding, i dont think they need to touch it to do these things. I'd go back and say that the car wasn't like this when you gave it to him and he should fix it

[h100vw]

Pressure bleeders are the way to go on these.

Could be it's sucked some air in. There's also bleed screws on the master cylinder which need to be done first or you keep pumping air around the system.

Gavin

[*thad*]

I had his happen to me on a non-vw. What happens is the fluid pressure is holding the worn seals in place, then when you change the pads and bleed some how a little air gets in resulting in the seals collapsing. New seals (or in my case new master because no one could get new seals) and it should be all good.