The Stovebolt Site Forums The Shop Area Engine Shop Brake Adjustment - Uneven Drag

I have a 53 GMC 9300.

New brake shoes and drums were installed by the PO. I have bled the entire system and the brake pedal is right at the top.

When I put the brakes on they pull slightly to the left. I went to adjust them and found that when spinning the wheel half of the turn has slight drag while the other half of the turn has no drag. This seesm to be the case on all four although the front seems a little worse.

I read the other posts but I couldn't find anything regarding this.

Is there some adjustment somewhere that I am missing ?

Dave,

Although everything should be true and round, sometimes it just doesn't happen. The truck is pulling toward the side that is adjusted a hair tighter than the rest. Provided you don't have a wheel cylinder leaking, I would fiddle with the adjustment until the rig stops straight and true.

Stuart

my bet is that the drums were not turned correctly or the shoes were not ground to fit and haven't yet worn to fit.

I would pull the front drums and examine the drums and shoe contact pattern.

wouldn't hurt to put them on a brake lathe and check them for roundness/concentric with bearing bore.

I don't agree with atomarc that adjustment is the probable cause. While the initial contact could be delayed by a loose adjustment, any pull after that is most likely a contact/fit issue.

Well, I'm going to try and just get along with everybody because I agree with KENC and atomarc.
I have the same high spot/low spot drag you described on all 4 wheels of my '53 3100 but she stops straight and true after careful adjustment. I would try what atomarc said first, and if it still won't stop straight then you'll have to dig deeper as KENC says. Try the simple fix first though, it worked for me.

Thanks Guys...

I agree with Waldo53, I will try the simple fix first as atomarc suggested. If that doesn't work I will start with KENc's suggestions.

Stuart
The cylinders aren't leaking. I was just concerned there maybe another problem when I felt the high and low drag.

When the wheel is on and I am adjusting from the back, which way is tightening, up or down ?

It might save me pulling a wheel back off to find out...

I read on another post about backing plate adjustment. Could this be part of the problem ?

Dave

That drag & release is pretty much present in all drum brakes. In a perfect world you might get them true. Adjustment has little effect on pulling unless it is way off. Hydraulic brakes are self equalizing. If it,s pulling there could be a little difference in the centering of the shoes. If it is all new it may even up when they are worn in.

Ooh, Ooh! I thought of something else. That first drag you hear as you tighten up the shoes could be a false indication. I tighten them up until the wheel won't turn at all. This centers the shoes on the drum. Then back them off until the wheel turns freely but you still hear a scraping sound.

I think of you move the tool up, it tightens in every case (or do I have this backwards?)

Good thought Waldo. You are right about the adjustment also. Moveing the spoon up on the outside of the backing plate tightens the brakes except Huck brakes, self adjusting brakes, or someone mixed up the adjusters.

There's always that little bit of drag in a certain spots, even after a brake job. It's just the way it is. If you can't feel any brake shudder in the pedal or in the steering wheel, don't cut any more material from the drums, it's a waste of time and material. A slight drift when applying the brakes could be an alignment problem or a tire problem. It will take some diagnoses to get to the bottom of it. If the adjustment is close, it won't pull unless one wheel is contaminated or a different shoe lining than the other. A lot of possibilities,
Scott