VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Drum Brake Backing Plate Repair and Restoration

Hello friends...

I'm working on the drum brake backing plates for my '37 1/2 ton pickup. I hope to someday use this truck as a daily driver, so I want the brakes to be durable.

Does anyone have experience with repairing the brake shoe rub pads? The pads stand about 0.060" above the backing plate, and the shoes have worn between 0.020" and 0.030" of that away:


My thoughts on possible repair methods are:

1) Clean the pads and try to add some brazing rod, then file the pads back to the nominal thickness. This is the easiest repair I can think of, but I don't know if the brazing rod will build thickness without making a huge puddle to file / grind off. I also don't know how well the brazing rod will wear with the shoes rubbing against them.

2) Clean the pads and use a MIG (or gas) welder to build up a spot to file back. This will add more heat to the backing plate, possibly causing it to warp. I think it would also be more difficult to work, but should provide a harder surface than brazing. I could also heat and quench the area after it has the proper surface finish to increase the hardness for improved wear.

3) I guess a third option is to file the pads down so they are all a uniform height of 0.030 inches... I wouldn't think the shoe alignment tolerances are that critical???

4) I could combine options 1 and 3: File the pads back to a uniform thickness, then braze little steel pads back in place and file these flat. Although this sounds easy enough, if one of the pads were to work loose, it would probably make a mess of everything in the drum.

5) I hate to leave them alone, but I guess that's an option too.

Does anyone have experience or other suggestions?

My approach to your problem would be to use a wire feed or stick welder. Run a weld bead down the worn area attempting to keep the remaining original flat surfaces untouched. Then, using a handy sander with a 4 or 5 inch disc and 24 or 36 grit, carefully sand off the crown of the weld until you reach the original surface height. You'll probably see some porosity in your weld after the finish surface is acquired, but don't worry about it, it will work just fine. I agree that using a torch may add too much heat with the potential for problems and braze is too soft.

Thanks... I hadn't thought about just trying to fill the groove. I'll go sand blast one of them and give the MIG approach a try on one pad and see how it goes. I have an extra axle for both ends, so I have spares.