Tracking down pull to left under braking...

[Project1970]

I've been tracking down a pull to the left under braking for a while now. I'm 95% certain it's the rear brakes that have been causing this, since the first set of shoes I pulled off were badly worn on the left but only partially worn on the right, and the set I took in today was cracked (overheated) on the left but not the right. Today, I replaced the parking brake cables, since the return springs on both were kinda toasted, especially the driver's side...but it's still got a bit of a pull to the left. Less, but still there.

The backing plate on the driver's side has some grooving on the 6 points where the shoes rub against it; is it possible that this odd wear (not present on the right side) is causing the driver's side to hang up to an extent? And if so...how hard is it to replace the backing plate?

12-bolt rear on my '70, by the way...

[NHRA59]

A pull to the left under braking condition means the right side is not working 100%. Most often a pull is caused by the frount brakes directly effecting the steering. I would look for a restricted rubber brake hose (disc) or wheel cyl. (drum) on the frount right side.

[jmanz69]

I agree with the ubove post. It's probably on the right side, and if it's on the rear I would look at the wheel cylinder being bad. It may not be opening. This would cause the left side to overwork and could be why you had an overheating problem.

[Blue Beard]

Having same kind of trouble.....Had headers touching brake lines.......Removed the headers and readjusted the brakes..............much better.

Don't know if this will solve all the problems......but I'll go from there......

[Project1970]

Hmm...I'll give that a check then....but I know for a fact that the left rear was dragging. I think the right rear adjuster isn't quite 100%.

No ideas on the backing plate?

[ChevLoRay]

The diameter (inside) of brake drums is critical, in that both sides should be within tolerances that allow for even braking. For example, I had a Chevy II that had gone to metal on the right front (before I bought it). I had that drum turned "to clean it up". The end result was that the car pulled to the right because the diameter of it was greater than the left front drum.

We often will replace shoes and have drums turned (if they're scored), but not always. Brake shops used to "arc" a new set of shoes to chamfer the leading and trailing edges and assure that the linings were "round", i.e., they were concentric to the diamter of the drums.

Unless a spring breaks, how often do we replace the hardware when we do a brake job? Not often.

On the backing plates, behind each shoe, there are several places that the shoes contact. When you pull the shoes off to replace them, you should see the shiny metal on the backing plates. Before you reinstall the shoes, take some white grease (lithium-based) and smear it on those places. Not too much, just enough to prevent the metal-to-metal contact. The grease won't melt, and it won't get on the abrasive lining unless you use too much and glob it on with reckless abandon. Once you have seen that the backing plates are worn, grooved, or whatever, you really have no choice but to replace it/them. You will have to pull the axle to replace a backing plate, but the backing plates are bolted to the ends of the axle housing.

[MOTHERTRUCKERS]

Check your brake adjusters to make sure they are not rusted up and not working, check the wheel cylinders to see if they bleed rusty brake fluid. If so flush the system of DOT 3 and add DOT 5 fluid. DOT 5 will not let your lines rust from the inside. Since I changed to DOT 5 my drum brake trucks are a pleasure to drive again. If you need backing plates for front or back on a 1/2 ton I have good used for 10.00 each.