Did a complete rear brake job including a pair of Pronto brake drums. Here are some videos of the problem. Wheel and tire with new brake drum. Bad wobble. Wheel and tire installed without brake drum. No wobble. Brake drum only. Bad wobble Bare axle. No wobble. So is it safe to conclude the brake drums are bad? The other side is worse. I cleaned the axle surface so its flat. Wheels and tires are new.
Is the bare drum shaped to fit inside the wheel OK? Take the loose drum and set it into the wheel to see how it fits the back of wheel. The drum looks warped or bent, like maybe the wheel hits that raised drum edge before the flange seats onto the drum?
No ***s in the drum that are supposed to go in a hole between two studs in the hub? You might run the drum (s) down to a shop or store where you can have them put them on the drum lathe and see if they wobble there. That should let you know right now if you have a drum problem or if you have a drum fits the hub problem. Also is there any mark on the drum or on the inside of the rim that shows that the rim hit the drum where it shouldn't? Older style drum brake wheels might not fit drums that are intended to be mated with disk front brakes and run disk brake wheels. In that case the first lug bolt you tightened down may have bent the drum.
Most drums are made in china. Pure junk. Rock auto sells centrics premium drums and rotors. As far as I know they are the only American made replacement drum and rotor co. With out going high tech.
Make sure the drums fit all the way on the axle registers, and flush with the axle flanges. That's what looks like could be wrong.
Install the drum and mark on the drum where it's the farthest out from the backing plate (largest gap). Remove it, rotate drum or axle and reinstall on different studs. If the same spot is still the farthest out, drum is bad, if a different spot is farther out, then you have an interference problem with drum and axle. A second check is to see if the brake shoe surface is round or does it wobble? Could be the brake shoe surface and axle face was cut correctly, while the wheel face somehow got out of whack during machining.
as stated above, new drums are made on the cheap - next to no quality control - just take drums to a auto parts store that turns drums, or machine shop. all new drums should be turned/trued before installing
Is that even the right drum for the application? Looks like it should fit closer to the lip on the backing plate.
Does it seat fully on the axle flange? The drum looks like a "one size fits most" to me. I would take them back.
An update, put the drum on backwards and it doesn't seat fully against the axle flange. The center hole is a little too small and it hangs up on a radius at the flange. Ordered a cone grinding wheel and will enlarge it slightly to fit.
The drum center has to be enlarged accurately, because the axle register locates the drum radially. Might be better to have the drum centers (or axle registers) machined.
I understand that, and why I'll use a cone grinder and test fit every few seconds. And as mentioned this is a $150 truck so third world solutions first.
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