I am trying to change out my u-joint on the rear. The problem I am having is that one of the bolts on the flange will not loosen or tighten. Is there any way to get this out easily? This is on a 94 4wd Pickup.

 

is it just seized? spray it with a good pentrator and brace the one wrench and pull like hell

 

Turn the driveshaft to a convenient angle and use the parking brake and transmission to keep the driveshaft from turning. Then use a boxed end wrench on one side to hold the bolt from turning if you need to, and put a 2' or so long piece of pipe over a breaker bar to give you good leverage while pulling on the other. Using 6-point wrenches and sockets help prevent rounding off the bolt and nut. Penetrating oil over night will help a lot also.

 

I guess I worded that wrong. The bolt is spinning but not coming loose even though I am holding the nut from turning. Basically the bolt is spinning inside the nut and not coming loose.

 

time for the drill or torch!

 

sawzaw

 

I doubt you have the room but if you can somehow grab ahold of either the nut or bolt head and pull as the other end is turning it might come out. Very effective with air tool speed. Small or needle nose vice grips may work if there's room.
If no room and since you have all the other bolts out you can pry a bit between the two flanges (better with a third hand) while spinning the bolt and nut apart. Its pressure pulling or pushing the bolt and nut apart while unscrewing that gets it apart.
If this doesn't work, be careful with the saw and don't accidentally cut into your yokes too much.

Good luck.

 

4 1/2" angle grinder

 

Any one of these will work.