Brake master cylinder help

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Jun 4, 2009
Pasadena, CA
Here is what I have heard throughout the forum.

I have heard that the full drum brake booster can remain and you can use a front disc and rear drum late 1970s master cylinder on said old brake booster.

I have purchased a 1977 master cylinder rebuilt from autozone, and I am worried at how slowly the piston returns. I fear that the spring or something is defective.

When I installed it, I bled the system, found no bubbles, and the thing had no pressure behind the petal.

So, in a list, first concern is strength of springs in master cylinder and whether it will cause the piss poor braking.


Going to need a bit more info than what was provided:

Are you four wheel disc?

Are you front disc rear drum?

If you are rear drum, have you adjusted the shoes?

If you are rear disc, did you remove the residual pressure valve from the master cylinder?


What do you mean 'how slowly the piston returns?'
Right, more clarification.

I am front disc rear drum, the rear drums are adjusted fine. The problem is there was no pressure when I pressed the brakes, it would go to the floor after I bled the system.

The piston in the new master cylinder takes about a good 10 seconds to stop, and when it does, it's not all the way back to the c clip. It's really stupid that I just bought this rebuilt and the damn thing doesn't function properly.
I ran disks in the front and drums on the rear on the original '72 drum brake master cylinder for more than a year - the residual valve was removed from the front circuit, everything else on master/booster was left alone
I have taken apart my old master cylinder and pulled out that residual valve from it, which caused it to work, but still wasn't great and why I want the new master cylinder to work. I think I'm just gonna exchange it for another one, this one didn't sit well with me >_>
Did you bench bleed the M/C? Did you re-insert/adjust the rod going from the booster the M/C plunger?

Just throwing out ideas.

Good luck
Okay, got my brand new M/C, but haven't installed it yet. What do I have to do to the removable shaft from the brake booster? It has an adjustable bolt for pushing into the master cylinder, and I tightened it a good bit.

What I'm basically asking is, how should the master cylinder bolt up to the booster? Should there be some travel or should that pin be pressed up against the cavern within the cylinder?



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