How much torque on the flange nut when putting a new seal on?

I watched the you tube how too and the guy marked it and counted the turns, unfortunatly I watched the vid after I had gotten the flange 1/2 way off. I am guessing just tight enough, but not too tight. Sort of vague though.

 

Make sure you lubricate the shaft with "lithium-based extreme pressure lubricant". The torque specs in the 68 chevy maint manual in the back says the pinion bearing preload for new is 20-30 inch lbs. Used 5-15 inch lbs. I have personally never performed this proceedure, so I couldn't tell you if new means a new seal or new gears. It makes sense for it to be gears and not the seal. Perhaps a second opinion?

 

thats for used or new bearings. are you asking for the torque for the yoke on the rear?

 

For what you did, 5-15 inch pounds is the correct torque to re-install the pinion nut.

 

It is the pinion nut I was asking about, but I guess I need the yoke too, I wasnt worried too much about that being exact. I just know that the seal will get hosed if I tightened it too much. I suppose the worst will be a leaky rear diff, which is what I had anyway.

I also heard that it is important to get the drive shaft and flange back on the same splines. Dont get it, does it really matter?

edit: I found that it is important for the balance of the drive shaft, probably doent matter for exactness here either, since there is no telling how it was originally on. I have had the drive shaft off before and just threw it back on so too late for that.

 

well if it vibrates theres only one other way the drive shaft can go on. lol.

 

Either I'm tired and missing something, or everyone is totally off...

We're talking about the pinion seal, correct? And you're asking about the pinion nut, right?

Changing the pinion seal isn't as straight forward as pulling the yoke off and reinstalling it. Some get away with just marking the nut and reinstalling it in the same orientation, but it's not right. And by removing the yoke without any reference point, you're really pushing your luck and very well might end up with a noisy differential a thousand miles down the road.

To properly change the pinion seal, you need to remove the axle shafts and carrier. Then you can set pinion preload with a beam style in/lbs torque wrench. You cannot "guess" the proper pinion preload either. You should reset pinion preload to factory specifications.

At this point, you may as well just get a master overhaul kit and the correct tools to completely overhaul your differential.

 

Yes, thanks for clarifying the pinion preload setting. I worded it like it was a simple inch pound torque on the nut, instead of a rolling resistance measure. That low of a torque you could practically do by hand, and we know that would be bad.
However, I see nothing wrong (nor do a number of others) with making an accurate reference point (a scribe mark and counting the exposed threads) before dis-assembly. Then reinstalling everything back as it was...provided you don't change out the yoke or the nut. A new seal isn't going to change the reference point either. The problem is, edog took his apart with no reference point, and now he'd be flying by the seat of his pants putting it back together. Getting it set right to be exactly where it was before is going to be next to impossible.
On the other hand, you can search around and find many guys who have torqued the nut back down (who have used different foot pound torques on the nut) and never had an issue down the road. Is it the absolute right way? No. But taking the diff all apart and redoing it all kinda sucks too, for what was supposed to be a "simple" seal replacement.

 

Well I know how to do it next time, lol.

I wonder how much luck I have, when I replaced the clutch a presure plate a while back I got a lot less shaking when I was done. I wonder if it was all drve shaft induced now. I torn apart the diff when I put on the disc brakes, and the rear end quieted down considerably.

Best lesson is to research before starting. I usually just cant wait to get started though.

Thanks.

 

I am now putting the nut back on and it is really tight. The problem is that there is a lot of slop in the yoke. Both back and forth and side to side. Now its 43 years old so I expect some, but if I keep tightening the nut will the back and forth slop go away? I am thinking that I tighten it down nice and good then back it off a little. What do you think?