Rear bouncing from about 40>32mph, what am I missing?
 

So a little backstory, a couple years ago I replaced the front rotors and pads, then last year I replaced the rear drums and shoes. All MC parts. Stopped great and smooth. FF to the end of last year and I start getting a bouncing in the rear when stopping. About 2 months ago I replaced the front pads and​ the rear shoes and bled all the lines. Still does it but I have a great pedal and it still stops on a dime. I get a very slight amount of pulsing in the pedal but I think it's just from changing the pads and not the rotors. They were in Perry good shape so I just sanded them some. I checked for play in the leaf spring bushings and they're old but there's no play. It's only when breaking. What else should I check?

Warped drums ?

Could they still be warped after being machined?

Also, with no pulling when breaking and no vibration in the wheel is it safe to say it is the rear? I do have a little pulsing in the pedal.

Does it feel like an abs problem? Did you bleed the abs valve?

[Edit] Wait nvm, i just reread the order things happened.

I've heard improperly torqued lugs can cause rotor warping, but i can't see it on a drum. Maybe heat though?

Pulsing in the pedal is usually indicative of warpage.
If your e-cables work good, pull out your release handle and apply them. That should tell you if the pulse is coming from the front or the back.
You'd have to have some pretty serious warpage to make the back end "bounce" though.

I used to have the hop - didn't go away until I turned the front rotors. It didn't make sense because I did not have the notorious symptom of the vibrating steering wheel when braking from high speeds. But I did it because it was the only thing I hadn't done when I replaced all of my brakes, and as soon as I did it it was smooth as silk. And it will give you an excuse to re-grease/replace your bearings and seals if you haven't done it yet.

Since then I meticulously torque down my lugnuts with a torque wrench to 100 ft-lbs and then re-torque them again after I have driven for a couple of days.

Also, since these trucks are so front heavy, I keep my rear tank full as long as possible, and I keep a full size spare tire in the rear of the bed. It amazes me how much better it drives with just that extra 150 lbs or so. Especially on poorly maintained roads.

Yea I'm starting to think you're onto something BLD. I've machined the drums, replaced the shoes, bled the lines and no change. I'm gonna order some rotor/hub assemblies from RA and go ahead and do it all including the bearings. I regreased them a couple years ago but I'll just replace them now.

So I just wanted to update this thread in case someone else stubbles in having the same issue. Replacing the front rotors fixed the issue. Smooth as butter now. The old ones looked fine, they didn't even have a lip on the edge and I drive pretty conservatively but something was up with them.