intermittant rear vibration

[crowt]

First post. Up here in Alberta Canada looking for some help. I have a strange issue in my truck: 97 FZJ80 72k miles w lockers. I just had the full-front axle service done by a cruiser mech. and he inspected and lubbed the spindle bushing. Vibration is exactly as described by user DMGINC21 (though no resolution given). very intermittent, seems to be caused by a rough patch of road, vibe starts off slowly, and then builds to a full-fledged shaking of the vehicle just like rumble strips, felt vibe mostly in the rear, and I can feel it in my seat. No steering wheel vibration, no pulling to either side. If I stop and reverse slowly, there is a thump....thump...thump with each revolution of the wheel/driveshaft (not sure which) coming from the rear. At all other times reverse is perfectly normal (silent).

I visually inspected the all U-joints and drive shafts did the wheel bearing test on each wheel - all seems fine. Also of note is that, if I drive when the problem is not occuring and I pull up the park brake lever, I get a very similar vibration. I'm going to pull the park brake drum apart this weekend and have a look.

please help

 

[crowt]

Took the rear wheels off this past weekend and pulled of the rotor/park drums sure enough the drivers side park brake was seized solid. The shoes actually expanded and latched to the drum as I was trying to take it off....took a lot of effort but it eventually broke free. Plenty of small springs and clips fell out in the process, but the main components look fine...no rust or corrosion. I disconnected and removed all the shoes, adjuster, levers etc, and reassempled the rotor and caliper without the park brake. Test drove for 50 miles or so, no vibration apparent. I will continue to test for a few days, if the vibe does not re-occur....I will clean, lubricate and put the park brake back together. I'll update the post in a couple of days.

 

[roncruiser]

Thanks for the update. Nice to see you almost have it in control.