Nasty Vibration

I have an 88 xj and i have been having this really bad vibration and i think its coming from the rear. last year it was so bad that hitting the brakes would make it much much worse. i ended up doing a brake job in the rear with all new parts drums, shoes and all the adjusters and stuff too. and it went away.
about a month later i changed the wheel cylinders. one got seized and took some life off the shoes.

Its mostly back now. between ~63-68 mph its the worst. im going to swap out the shoes again to see if that helps. anything i should be looking at also? i quickly checked the rear drive shaft u-joints and the seem good. the front wheel ujoints might be on the way out. but i have not experienced this kind of a vibration from those before.

i do have a broken leaf spring that i will be changing before the winter.

Im not sure if anyone has one of those vibration to speed it might be this charts.

Had a guy ask for help figuring out a shimmy at speed a few weeks ago. He had already changed drive shaft u-joints, thinking that was it, and said it got worse when he rotated tires front-back but still felt like the rear shaking and got worse when braking.



I jacked it up, put it in gear and you could see about 1/4" wobble at the tire tread. Measured at the wheel and found lots of run out as well. Pulled the wheel off, cleaned off a ton of rust and dirt from the wheel and axle face. After that it ran true and the wobble was gone. Stupidly simple fix.

I think I'm going to check that. I don't think it's a driveshaft wobble I'm not sure it has enough mass to shake it this much. Also what's the chance of a wheel being balance with no weights on it?

Balanced, no chance.

got a chance to run it up on jack stands and it wasn't too bad on the rear. had a little vibration. i think i have a bad bearing in the transfer case on the front shaft output side. with the 4wd on the front is a bit noisy and with a bit of vibration but its more noise than vibration.

i did notice a leaking brake line in the rear and a slightly out of round and slightly dragging drum.