5 replies to this topic

[bluemini1979]

I have upgraded my estate (1976) to front discs 7.5” and have kept the original single circuit cylinder and the valve on the rear subframe. Bled the brakes out and definitely no air coming out. Used eazibleed and pumping the pedal but it is still down the bottom. It does go hard about 1/2 inch from the floor and doesn’t pump up. Any suggestions to where to start. Everything is new apart from the subframe valve. I did notice the valve rattles when shaking it when off the car. Is it supposed to or is there a problem with it. Is that a good place to start?

Thanks David

[Spider]

A common issue with new calipers is the seals in them maybe a bit too dry to allow the pistons to self adjust.

 

Take one pad out at a time, pump the piston out (using the brake pedal) about 10 mm and then push it back, refit the pad and move on to the next.

 

Doing this will lube up the seals with Brake Fluid and it may help give a better pedal.

[bluemini1979]

There not new calipers. I had removed them from my other car to fit onto this one. They worked faultlessly on there. Could there be air trapped behind the piston. If I was to do as you suggest and pump the pistons out and then try bleeding again?

Edited by bluemini1979, 01 June 2018 - 08:14 PM.

[Spider]

It can't hurt, but as they are used, they will likely be well lubed, unless they have been sitting around for a while.

 

The other thing of course is to be sure the rear brakes are adjusted up. As a test here, pull on the hand brake and see if it will improve the pedal.

 

Even if the Pressure Valve was fault, it wouldn't explain the low pedal.

 

You can try locking off one brake at a time with line locking pliers to see if one particular brake maybe causing this. Even if you find one that suspect, still go through all the others.

 

Lastly, as it doesn't seem to come up even when pumped, I'd be suspect of the Master Cylinder, but check all else first.

[cal844]

My 1980 CE with black tag cylinder has a long pedal( the car has 7.5 disc conversion new last year, new wheel cylinders and rear subframe pipes this year) but once it takes up the play in the system the pedal goes solid and stops the car well

[bluemini1979]

Removed the valve on the subframe today and replaced with a tee piece. Re bled the brakes and the pedal goes solid just above the clutch pedal level.
I’m guessing this suggests the valve on subframe is at fault