I just replaced the pinon seal on my 71 8.5" rearend .Can someone please help me with how much torque is required on the nut.Also Ive heard about a crush sleeeve,where is it and what does it do?
The crush sleeve is between the pinion bearings and is what sets the bearing preload.Once this has been set you do not want to tighten it anymore.Torque the pinion nut to about 160-180 Lb. ft by hand and you should be fine.I also put a little Loctite on the threads. If you over torque the nut,you will have to get a new crush sleeve,but 180 lb.ft wont make it any tighter.
OH boy here we go again. I am going to copy this for my web site...lol. Ok well there is NO torque for the pinion nut per say... Lets start with the crush sleeve. The crush sleeve is between the inner and outer pinion bearings. The sleeves job is to keep the pressure outward against the two bearings. The crush sleeve as in its name is to be crushed upon final differential assembly and keeps the bearings pressure consistent in the bearing cups. NOW the Nut at the time of assembly will take 100-180 FT Lbs. (depending on the size of the sleeve) to crush a crush sleeve to the point at which the bearings are seated into the bearing cups/races. At the point of contact by both bearings into there matching races/cups you will start a pre-load pressure into each other...this is usually a inch pound measurement and about 20-25 or a slight drag by hand with NO RING GEAR installed. The pinion nut new is usually pre crushed locking nut...but we also use lock tight and I personally stake the nut to the thread with a punch and hammer. Now back to your question... Amount or torque to re install the yoke etc. Just tighten the nut tight as you can with holding the yoke ...you can hold the yoke with a large monkey /pipe wrench. IF the the nut tightens to the piont at which you have a tough time turning the pinion you will need to replace the crush sleeve. Bad news here, you will need to re remove the seal yoke and the outer bearing...at least on a 8.5 this is a job that can be done from the front and the pinion intacked. Other rears like the 12 bolt and 10 bolt chevy you need to remove all of the guts. If the pinion feels good like it did or slightly tighter but still smooth you are good. STAKE that pinion nut in 2-3 spots with a pointed punch into the pinion thread and let it be. I am sure there will be some comments to this so I am just being realistic to what you can do with what you have. Any shop will just tell you ' oh you need to buy new crush sleeve and a inch pound torque wrench ' and so on. Good luck with the diff. Jim
Thanks for the instruction and the detailed information .I put it back together this afternoon and it feels right . when the mystery factor is gone it makes sense. To gswewart no puller was needed. The help may have saved my rearend....pun intended
Next time you do this, loosen the nut with a torque wrench. If it takes 120 ft lb to remove it, tighten it back to the same value. If 180, tighten to 180. We did this when i was a line mechanic at a Buick dealer in the 60s. Never had one come back.
That sounds like a risky one there, especially when working on old iron nowadays...firstly for the simple fact that static and dynamic torque are never the same value, secondly who knows how much corrosion & contamination have added to the breakaway torque all by itself over the years. Even with nice clean parts you could be putting 10-20% more squeeze to the crush sleeve than it had with the original installation. I've always erred on the safe side & simply used an inch-pound torque wrench to check pinion bearing preload whether the crush sleeve is being reused or not, as Jim pointed out. It's just plain cheap insurance to spend some extra time to keep from toasting a lot of expensive parts. Devon
X2! I learned the hard way. 100+mph let off the gas and it felt like I had a u-joint coming apart, and I was wrong! It was my rear ou: