C15A brakes jamming

[Richard Farrant]

Originally Posted by harrygrey382

This is why I was thinking about wrong lining thickness. I just can't remember what the drums were like to get on.

When fitting new shoes, especially if relined, they should be laid in the drums to ensure they are radiused correctly. You might need to take a drum off to check unless you remember doing it ............. although 12 years is a long time!

[harrygrey382]

Originally Posted by Ghost

Hello all,

I agree with Rob Love - have you checked the rubber brake hoses?

I have had two instances of the rubber brake hoses swelling & the lines become so restricted they act like a valve. Push on the brake pedal & the brake shoes do as they are designed to do.......... but when you release the brake pedal, the fluid won't return to the master cylinder - thus jamming the brakes on.
I have had this happen to a GMC and a White.
It kept me looking for the problem for ages & the first time it cost me an unnecessary brake rebuild.

It may be worth a check - especially after 12 years.

Rob.

Thanks, sounds logical but doesn't explain why release the pressure at the bleed nipple doesn't release the shoe tension

[Rob Beale]

In the Chev master cylinder there is a tiny hole that allows the fluid back into the reservoir. If the seal in the cylinder is too long, it may be obstructing that hole. You should be able to see it through the reservoir filler hole. A thin wire or needle inserted in the hole will confirm if there is a restriction or not.

Rob

[motto (RIP)]

If it was a hydraulic problem then opening the bleeder at the wheel cylinder would release the brakes on that wheel at least whether the blockage was caused by a master cylinder fault or a restricted hose.
Yes, it is possible for components to corrode over time even if assembled with rubber grease. A lot depends on the quality of the grease and atmospherics.
I don't know the exact brake set up that is causing problems here but running the adjustment out and back may do nothing to retract the pistons.

David