Having an issue with one of the Corvair's brakes

"Demon-Xanth knows how to operate a street." (demon-xanth)
08/21/2014 at 09:37 • Filed to: None

For some reason the shoes on one side are acting like they don't center right. Replaced the springs and shoes with all new parts on both sides, only one is doing this. This side acts like it intermittently wants to grab and try to twist and cam locked. Are there any drum brake aficionados that can give me an idea of what's going on?

Here's a ton of pictures:

DISCUSSION (16)

CalzoneGolem > Demon-Xanth knows how to operate a street.
08/21/2014 at 09:39

I just came here to say "Fuck drum brakes! Fuck them hard!"

RamblinRover Luxury-Yacht > Demon-Xanth knows how to operate a street.
08/21/2014 at 09:47

I'm prepared to say that's a terrible design. Most drum brakes use a pivot opposite the cylinder for a reason, not with the cylinder playing third-degree lever. I know the balance is the same in theory, but in practice it isn't. This design allows both brake shoes to move off-center together.

I'm not sure I quite understand the problem, but you can probably bludgeon the shoes with a deadblow hammer to where they need to be.

crowmolly > Demon-Xanth knows how to operate a street.
08/21/2014 at 10:18

Kinja'd!!!

Throw some anti-seize on the threads here. Trust me. How well does it rotate to begin with?

And the shoe on the right looks to be pushed to the right.

Lefthand shoe is near the backing plate ridge, righthand shoe is near the edge of the plate.

desertdog5051 > Demon-Xanth knows how to operate a street.
08/21/2014 at 10:19

I had a similar problem on a different make. Assuming the drum is good and was turned so it is centered. I loosened the bolts holding the slave cylinder to the backing plate and had someone apply pressure to the pedal as the wheel was rotated and tightened the bolts. It seemed to help.

RamblinRover Luxury-Yacht > crowmolly
08/21/2014 at 10:22

Yep on both. A case of "hit them suckers back to where they supposed to is".

Demon-Xanth knows how to operate a street. > crowmolly
08/21/2014 at 10:31

Well, that's the issue exactly.

Demon-Xanth knows how to operate a street. > RamblinRover Luxury-Yacht
08/21/2014 at 10:37

As soon as I use the brakes, they go back.

Demon-Xanth knows how to operate a street. > CalzoneGolem
08/21/2014 at 10:38

$600 for a front disc kit, no available rear disc kit.

CalzoneGolem > Demon-Xanth knows how to operate a street.
08/21/2014 at 10:47

This is exactly what is wrong with the world today.

RamblinRover Luxury-Yacht > Demon-Xanth knows how to operate a street.
08/21/2014 at 10:54

Sounds, then, like you may have an issue with overall alignment causing one piston to bind. With only one piston extending, it pulls the other shoe out of alignment with it. It really ought to be able to press hard enough to center up, extend the left piston, and apply both shoes, but it may not be. The only other "both shoes float together" brake system I've seen was on a John Deer tractor, so that doesn't help much.

Something's sticking is, I think, the short answer - as to why one side of the cylinder isn't extending with any force, you'll just have to mess with it to find out. Loosening the cylinder so it can find its own alignment with the drum bolted on *might* work.

Bad Idea Hat > CalzoneGolem
08/21/2014 at 11:42

I see drum brake threads and just feel the hammer in my hand.

CalzoneGolem > Bad Idea Hat
08/21/2014 at 11:45

I will happily pay someone to fix any drum brakes I ever have.

Bad Idea Hat > CalzoneGolem
08/21/2014 at 11:58

I probably need to have mine looked at when I take the car in for a muffler replacement.

Welding and drum brakes; two of my nemeses.

CalzoneGolem > Bad Idea Hat
08/21/2014 at 12:03

The only good thing about them is that they seem to last a long time.

Demon-Xanth knows how to operate a street. > desertdog5051
08/21/2014 at 15:35

loosening the bolts and just pushing down, and reversing which of the blue and black springs were on top seems to have worked enough, the center isn't nearly as far off.

desertdog5051 > Demon-Xanth knows how to operate a street.
08/21/2014 at 15:56

Great news. simple solution to a big problem. I don't miss drum brakes at all. I have a truck that has drum rears and I need to put new shoes on. Oh Boy.