1992 F-150 Flareside XtraCab. I just replaced all 3 U-joints and the hangar bearing with new ones to alleviate a highway speed vibration (between 40 and 65 mph). The truck now runs silky smooth at those speeds but now I have the same vibration at 30 - 40 mph. Do I need to align the hangar bearing perfectly with front and rear driveshafts to ensure a balance or is it not critical?. I noticed that the bolt holes in the new hangar bearing mounting bracket were elongated sideways. Is this for adjustment?? I marked everything before removal and put everything back the same and greased all the joints (and yoke).

 

I had some problem with that when I had my U joints replaced. I tried everything I could think of including using hose clamps as a counter weight. The only thing that helped a little was moving the carrier bearing forward a bit to increase the amount of engagement with the trans splines. I still ended up getting the thing re-balanced though.

JohnF

 

I had a similar vibration after having my u-joints replaced. At about 36mph it would get a nasty vibe enough to shake the wheel out my hands almost. I had just rotated my tires when the u-joints were done, and my problem was that the tires needed rebalanced.... i couldn't believe that just rotating the tires front to back (unidirectional tread)
would have caused that problem... but it did
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Brian
95 F-150 4x4 ExCab/SB 351 6"/35's