Brake Lock-up Issue on 1970 C10

[BBoatner]

Under hard braking going down a very steep hill, only the right rear wheel of my 1970 CIA with power brakes locks up. The resulting fish tailing is sort of fun on an empty road at slow speeds, but I hate to think of this happening at higher speeds in traffic.

I did a complete brake job including all new hoses, wheel cylinders and master cylinder. Aside from the lock-up issue, the brakes work well. I tried adjusting the guilty wheel but the problem persisted.

Does anyone know what would cause just one rear wheel to lock up? BTW, the truck has 4 wheel drums just like it did from the factory.

Thanks!

 

[jef5150]

each drum has a "star" self adjuster at the bottom that sits in between the bottom of your brake shoes,they are suppossed to "self adjust" each time you apply your brakes going in reverse. Try reverse braking a few times and see if that helps.You can get a screw driver into the slot(opposite side) and push the star up or down to adjust manually,you dont have to take the wheel off just crawl under the truck and you should see a small slot.But going in reverse and applying the brakes"hard"(dont slam them on)should do it.


jeff

 

[BBoatner]

Thanks Jeff. I did try backing off the adjuster to see if that would cure the problem temporarily. Alas, the wheel still locked up.

The parking brake cables that feed into the rear wheels seem a little worse for wear. I'm wondering if the cable may be sticking and keeping the brake from releasing? Think I'll just disconnect the parking brake and see what happens.

 

[Soba_03]

Brakes grabbing...

Bboatner....

This is funny..... Ok part of my last weeks projects was the same problem. Except it was on my l/h front brake. So here is what I found on mine.

First, I can tel you that I changed out a rear wheel cylinder a few weeks back and thought I had it bleed out well. Now again I say that my problem is with my l/h front brake. So here is what I found on mine and I hope that it may help you.

First thing I did was popped open the master and checked the rear chamber for fluid level. Well it was low, with this it was causing my rear brakes not to function as well, causing my front brakes to compensate. I added more fluid and not pedal is better and front brake doesn't grab. If you did all your brakes I would recommend checking fluid levels. Additionally, if you just put shoes on it, did you notice if the leading edge of the shoes were beveled. IF there is a sharp squared of area on the brake shoe friction pad i've been told that this can also cause a grabby brake. If you have one that is grabbing after the brakes are applied for a second or so then you also may have a bad wheel cylinder that is holding pressure for just a while longer than the others before it actuates the shoes out to the drum. If you haven't changed them recently for the 4 or 5 bucks it's a good investment.

Good luck....