Brakes, who knows about em? huge headache here

[Dane]

MK1 braking system


when i purchased the car, i had SOME braking power, it sat for 10 years but i did actually have some.

fast forward to now

i removed the master cylinder and purchased a new unit
i removed the brake booster and painted it


I bench bled the master and reinstalled both units to the firewall
When the car is OFF, i can build pressure in the pedal to where it feels somewhat firm, but as soon as i turn the car on, the pedal goes all the way to the floor very loose right away, no pressure at all. while running, if i pump the brakes as fast as i can i get a hint of pressure built up, but as soon as i stop pumping for a second it will go back to the floor with zero effort.

I went and replaced both rear wheel cylinders and made sure everything was nice and tight.
Bled the entire system from right rear- left rear- right front - left front.


this has been a constant headache because ive been fighting to get on the road for weeks and this is whats holding me up. does anybody have an idea on where to look?

[VAGatHeart]

Invest in a good parachute.

[palmer]

Are the bleed valves on the calipers facing upwards?

[Dane]

Yes they are

[veedubmechanic]

did you put a new gasket between the master and the brake booster?

[Dane]

Yes, one was supplied with the new master

[veedubmechanic]

You must have air in the hyd system then or the master is leaking internally

[Jigs]

I had a problem like this on an old grand cherokee and it ended up one of my rear drums was siezed up.

[Dane]

i just replaced both wheel cylinders

[shawn o]

I had a similiar situation once and it turned out to be a faulty check valve for the vacuum on the booster.

[veedubmechanic]

Have you adjusted the rear shoes? If they are way way out of adjustment it will have a air in the system like feeling.

[Dane]

Ill try to source another check valve. I have both vaccuum openings plugged up on it. A friend had suggested I adjust the brake shoes. I noticed the shoes themselves were just about done for anyway. Maybe time for new ones

[veedubmechanic]

Have you adjusted the rear shoes? If they are way way out of adjustment it will have a air in the system like feeling.

This