Brakes staying on

[dcburton]

Hi there, after having my Octavia estate come home from the MOT station requiring new rear brake pipe assemblies & a new front to OSR pipe, I set about replacing including making up the new pipe.

Bleeding took a while & in the end I had to get a pressure bleed system as the kids were getting fed up pumping the pedal!

I now have good firm pedal but the pressure is staying on, all 4 wheels are locked solid

I have had the master cylinder off & checked over by a mechanic but he could find no problem.

Getting beyond funny as without the car I have to get the bus & for a 7:30 start I have to get the 5:45 bus into town :(

[giandougl]

The only thing that would keep all the brakes firmly ON would be the brake fluid pressure release mechanism in the master-cylinder, not releasing the pressure from the brakes, back into the master-cylinder...

Check pedal attachment to master brake-cylinder for correct positioning.

[Neily03]

I thought bleeding by pumping the pedal was very bad for VAG cars as it will wreck the seals in the master cylinder?

[dcburton]

The only thing that would keep all the brakes firmly ON would be the brake fluid pressure release mechanism in the master-cylinder, not releasing the pressure from the brakes, back into the master-cylinder...

Check pedal attachment to master brake-cylinder for correct positioning.

I have tried pulling the master cylinder away from the servo as a way to check this is not happening, No difference

I have even tried pulling the fuse for the ABS/ESP but still my brakes are still locked solid, the system is getting a good pressure test anyway 

[cheshire_cat]

not been using mole grips to seal off flexible pipes??

[dcburton]

Update

went back to basics, I managed to get fronts moving readily enough, just the surface rust from sitting idle for a few days impeding motion,

the backs on the other hand not so much.

nemesis thy name is oxidation

removed OSR calliper & found the pads were sticking due to rust under the slider plates, also having a close look at the calliper it is quite a bad way, aluminium is not a metal, it's a fungus

looks like a pair of callipers is on tomorrows shopping list 

[butchvrs]

If you bled the brakes by pumping the pedal you can smash the actuator rod through a metal plate at the back of the servo, which locks the brakes on because the rod can't return.

I now know of 4 cars that have had the same problem, mine included.

 

Unfortunately the only way to solve it is a new servo, they're not cheap and an absolute bi**h to change.

[dcburton]

If you bled the brakes by pumping the pedal you can smash the actuator rod through a metal plate at the back of the servo, which locks the brakes on because the rod can't return.

I now know of 4 cars that have had the same problem, mine included.

 

Unfortunately the only way to solve it is a new servo, they're not cheap and an absolute bi**h to change.

this would appear to be the problem, I am now going away to blub like a baby :(