my rear pinion keeps loosening up on my 9 inch rear axle. i am pretty sure that the bearing is shot. my question is if i replace the bearing will i have to re-shim and or set the pre load??? can i just use the old shims????

 

KEEPS Loosening up? You mean the yoke nut is backing off?

You are supposed to reshim your rear, but it will be so close you probably don't need to worry about it.

 

You should only have to reset the preload if you're only changing the front pinion bearing. If you do any others, you might as well kit & reset the whole 3rd member because of the amount of disassembly you'll be doing anyway.

 

well i have tightened it several times and it keeps loosening up on me. thats why i am thinking that the bearing is shot.. i can take the pinion housing off right??? by the bolts that hold it on the 3rd member. it has been a while since i had a 9 inch apart. if i do the bearing i was plannin on shimmin it.

 

The nut backing off doesn't indicate a bad bearing - it indicates a worn nut. If you can't get a new one, pull that one, hose it off with carb or brake cleaner, dry the pinion threads, put some threadlocker on it, and torque it to spec.