Bad Wheel Bearings / Hub Assembly???
 

Took the truck for a spin after replacing the front U-Joints only to discover a very noticeable shutter/vibration coming from the LF Wheel. The shutter/vibration happens every time I bring the truck to a relatively aggressive stop, however, the shutter/vibration doesn't happen if I bring the truck to a fairly slow/non-aggressive stop. The shutter feels a lot like the LF brake is hanging but goes away shortly after I let off the brake & begin accelerating. Never noticed anything out of the ordinary while pulling the rotor, caliper/pads, hub and axle while repairing the U-joints...everything looked fine..the u-joints went back together perfect & there's no longer any pulling/grabbing or noise from the steering wheel/wheels while turning tight corners. Took the truck to FIRESTONE for their $15 checkup & they found slight play in the LF tire & recomended replacing the LF HUB assembly. I did notice the shutter/vibration before repairing the u-joints but thought the worn u-joints were causing the s/v. I threw in the pic below showing part of the u-joint repair on the RF wheel, you'll notice the 2-TON bottle jack providing back pressure on one of the hub assembly bolts which I hoped would help reduce the chance of separating/screwing up the bearings. I also used the bottle jack trick to pop the rotor loose from the hub! The bottle jack seemed to help on the RF wheel but it seems something may have gone wrong on the LF wheel(?) Anyway........ any thoughts regarding the most likely cause of the RF wheel shutter/vibration is much appreciated!

replace the rubber bushings on your calipers, bad ones will give you this type of vibration. I thought the guy that told me this was mad, but after a week of being frustrated by the vibrations I changed them and problem solved. It only cost 12.00$ for the replacement kit for both sides. Just a idea.

Did you check front rotor runout? Might want to have the rotors machined. We use the on truck Pro-cut machine works really well with 4X4 trucks.

It sounds like your going to need to replace the hub bearing unit. You can do it yourself but its a workout!

If you used a bottle jack on the rotor to loosen it then you've quite certainly got a bent (warped) rotor. Check the run-out on it. Maybe you'll luck out and it will be the rotor. Did you clean it up well with brakekleen before reinstalling it? Get any grease on the brake pads? That can cause problems too.

However, if there's play in the hub, then the bearings are almost certainly nearly gone. Did Firestone rule out the ball joints as the source of the play? You didn't state how the hub seemed when you had it off the truck to replace the u-joint. How'd it sound when you spun it ? Any roughness while rotating it? Perhaps it sounded like a dry bearing spinning? The hub's days may be numbered. But, maybe its a bent rotor.

I will second this

A bottle jack to break it lose? When I did the bearings / rotors on my 94 the very first time, they practically fell out of the spindles. The hardest part was getting the stub shaft nut off!

Update.......
 

As it turnes out, I somehow ended up twisting off the head and part of the lower brake caliper mounting bolt using a cheater bar to reinstall the caliper bolt [dummy] The "shutter/vibration" was actually coming from the RF brake caliper pivoting on the top mounting bolt and hitting the inside of the rim. :o Kept checking my u-joint work for problems and never noticed the broken caliper bolt! :o

Double checked all the suggestions above and everything else looks good. All in all, the hubs were a huge fight at first but after picking up the heavy duty hub puller and using the bottle jack to assist, the hubs finally broke free from all the rust. Still not sure about the play in the LF wheel that Firestone found but I'll check the ball joints for sure... anyone have a good diy test for ball joints?

Really appreciate all the help on this!

I have a difficulty on removing the ball joints on the wheel hub assembly. The lower ball joints is an integral part of the steering knuckle.

(?) Don't recall having to remove the ball joints, since I was just replacing the front rotors.