Vibration shows up in the 90 Blazer (fullsize) Crawl up under it with a tire tool and check the "U" joints. No noticeable wear. Jack up rear axle, "feel" the wheels as they spin and shake em back n forth looking for bearing issues, drivers side "feels" a bit rough. Replace bearings and seals (192 k on the truck anyway might as well get it done now) Had to build a slide hammer bearing puller, those bearings were in there! Long story, Auto Zone rented me a puller that was basically boat anchor material, it wouldnt even open up enough to snag the backside of the bearings, call em, no luck, they dont have what I need and dont appear to care, borrowed a home made puller from a friend I know, it just has a rather large nut on the end, I guess for pulling a sissy bearing it would work, but my truck definately is no sissy. So..go to the net looking for a puller, found em, see what they look like, and go to shop to build one, finally a day after I started had one bearing out...whew!
Brakes needed fixing too, got it all, shoes, cylinders, springs, and drums, test drive...still vibrating. Pull drive shaft, immediately see "U" joint is froze up, cool, have one in the glove box (Im dragging a boat rigged out for river diving everywhere I go, I keep a "U" joint in the truck as well as a front bearing assembly and a bearing set for the boat trailer with me) Anyway replace, test drive, still vibrating, disgusted, go in house and piss around a while, "Epiphany"! I remembered I only put the retaining clips on one side of the "U" joint. Pull driveshaft again, yep dumbass forgot the clips, put em in, she's back to a smooth ride. I knew (hoped) it was probably "U" joint related, its hard to tell sometimes when a cup has frozen up until you take the darn thing apart. I really needed to take care of the other stuff too, just happy its back to regular service. Now I need a paint job...
Charles