I have a method of checking backing plates for warpage. The stuff is old and can get bent. I attach a strap to the hub and measure thru a hold in the end. I measure from the strap too the pads that the shoes ride on. If the measurements are off, the shoes will sit crooked in the drum. They don't work well like that. I note the dimensions and work to get them all close. I beat the plates in if needed with a sledge or pull them out with a bar with pads. All extremely crude. Friend welds them up and machines them down. I think my way is fine and cheap. I also have a way to check a rear end for warpage and how to straighten.
I suspect my backing plates on my GM 10 bolt are deformed by someone attempting to pry the drums off when they were stuck. I appreciate the measurement method. I would like to know how you levered the plates or unpuckered them. They have to come out, not in... How long was your bar? And what did you use as a fulcrum? Knock the car off the jack stands at some point. Thanks for the practical tech tip. Edit; holey crap is that what the rusty tube is? I gather the cutting torch hole is not related (?)
That rusty tube is in fact the pry bar for bending them outward. The very end part grabs the plate lip and the middle part pushes near the center of the plate. It is 4 ft long. The super nice hole is not part of the process. The hammer is for bending in.
I've had to do this with a couple pairs of reproduction backing plates from a reputable firm. Think they must warp badly when being stamped out.
The Jalopy Journal
