If you are installing a new u-joint, here’s a quick way to dramatically reduce its lifespan: Over-tighten the bolts on the straps that hold the caps in place.
If you crank on those small bolts until they no longer turn, you risk distorting each cap so the needle bearings inside can’t rotate properly. Even if they can rotate, there’s so much pressure they build heat, cook-out the grease, and kill the u-joint.
Exact specifications vary according to the size of the u-joint, but those bolts should only be tightened to around 20- to 30 lb/ft. Less is better than more. Many of the bolts come with dabs of Loctite on them, so don’t be tempted to crank them a little tighter because the recommended torque “feels” too soft. If the instructions that came with the new u-joint don’t specify a torque value, Google-search the internet for that model number and come up with a value.
A final check when assembling a u-joint is that when you hold the driveshaft horizontal, the u-joint should “fall down.” If the u-joint doesn’t swivel freely either the caps are too tight, the snap rings are the wrong thickness, or the snap rings have been installed incorrectly.
