8.5 posi from a 73 nova in my 68 Camaro. pinion seal starts leaking so I took off yoke and replaced seal. I bought a new GM nut and put it back on with an impact. I knew it would need to be torqued to about 150 lbs, but I never thought my impact would over tighten. Well I was wrong. The old nut had 2-3 threads sticking out of it and when I got though with the impact there are now 5-6 threads sticking out of pinon. I backed the nut off a couple turns then retorqued with a torque wrench to 150 but it went back close to the same place. Did I damage the sleeve and thus in danger of ruin my bearing? I have put the driveshaft back on the car, so it hasn't been moved yet.
There is a crush sleeve in there that when over-tightened will crush more and will change your pinion depth. Hopefully Freddie (big gear head will chime in and save the day !)
My question is, does the flange turn freely or snug with a large pipe wrench weight on it? I asked this because in our shop we had a long bar that connected to the flange bolt holes, made my Kent-Moore . They were used to determine how much effort was there on the tightened nut against that bearing. I doubt its used any more.
If in doubt, I would do it over.
The crush sleeve will NOT change pinion depth, it only affects bearing preload. If you have not driven the car remove the pinion yoke and front bearing, replace the crush sleeve and reassemble with a new crush sleeve.
Do not use an impact to install the nut and crush the sleeve it will hammer the bearings. Use something to keep the yoke from rotating and use a breaker bar and socket to determine correct preload.
Pinion depth is controlled by pinion shims between the rear bearing and the back of the pinion.
You are going to need to remove the axles and differential to fix this. You can not measure pinion bearing preload with the differential installed. With the differential removed you can remove the yoke and pull the pinion out from the rear. Then you will have access to the crush spacer. Install a new spacer and start the process of setting the bearing preload.
It would be very hard to over tighten the nut to get 2 extra threads to show. I'm guessing that the pinion nut was backed off a little to begin with, and may have been part of the reason that the seal was leaking. I'm not doubting that it is too tight now, but it was probably too loose to begin with.
If you are going to the trouble of resetting the bearing preload I would recommend replacing the bearings while you have it apart. The pinion bearings turn 3 to 4 times more than the differential bearings, so they are a little more critical than the others. It is easier for me to set the preload on new bearings than old bearings. You never know just exactly how much preload to put on old bearings. Just about every rear end that I have disassembled had about 2 inch pounds of preload on the pinion bearings. Most books call for around 10 inch pounds when reusing them. That just doesn't seem right to me, and I almost always feel some roughness in the bearings when I do it that way. If you try to set them to about 2 inch pounds then it's hard to tell if you are feeling the drag from the bearings or from the seal. New bearings are much easier.
No. If it is noticeably tighter than it was before, then it is too tight. And... you said it is.
Freddie is right on: "Just about every rear end that I have disassembled had about 2 inch pounds of preload on the pinion bearings. Most books call for around 10 inch pounds when reusing them. That just doesn't seem right to me, and I almost always feel some roughness in the bearings when I do it that way. If you try to set them to about 2 inch pounds then it's hard to tell if you are feeling the drag from the bearings or from the seal. New bearings are much easier."
The only time I have re-used old bearings is when I KNOW it is set up correctly, and I can mark and put the nut back EXACTLY where it was. You used a new nut, so that would be impossible. The extra threads may be partly because the nut isn't as thick, or as Freddie said, the old one was loose.
ONCE YOU GO TOO FAR ON A CRUSH SLEEVE, YOU MUST REPLACE IT (well, there is a way to re-use it, but it isn't for beginners).
I lost a complete rear differential - driveline - manual tranny years ago in Texas on my F350 because an @SShat mechanic had overtightened a rear differential crush bearing - then backed it off.
Unless you mark or scribe the exact location of the nut prior to removal,
you run the risk of destroying your rear differential.
What's worked for me is to unbolt the backing plates and hang them with wire. That saves from having to bleed the rear brakes. Then remove the shackles or T-bolts (and what ever else is retaining the rear-end). Then lift the diff with your jack so as to jockey it out from under the car. Then load it up into any truck and TAKE IT TO A SHOP that knows what they're doing.:grin2:
I have hammered the crush sleeve on a bar about the same diameter as the pinion to lengthen in the past. This was done on low powered daily drivers though. If you have that much power I would get a new one. Setting up a rear end is very technical if done correctly. I have seen guys use impacts before but I never would. I also have had friends run a rear to death because of pinion depth being to excessive.
Now that idea sounds like a winner, Fred! I have a friend that is a technician at the Chevy dealer. When we were younger he used to do work on the side. I ask him to rebuild my 12 bolt rear back in 1997, which he was glad to do. I purchased the Ring & Pinion and the Ring, Pinion Installation Kit, and the axle bearings from Summit Racing. I did like you I just removed the 4 u-bolts and the shackle bolts and rolled the rear out from under the car. I took the tires off and loaded it on my truck (with some help) to take to the car wash. I sprayed it down good with some Purple Power degreaser and used the degreaser from the car wash while spraying with high pressure mixture. It turned out really good and clean. Kenny said he was proud of me when I dropped it off to him. He called me that afternoon to tell me I had a problem. He couldn't get the pin and bolt in. He asked If I changed anything and I told him about the rear just came with the axles no gears. I had bought a posi unit from out of the trading post. He told me I either had a series 4 carrier or a truck carrier. I got on the phone right away to the Camaro parts man in my area and told him what I needed. He had a rebuilt series 3 posi carrier for $275. I took it to Kenny and he called me that night to come pick it up. I was telling my story at work when we were on break and Larry was working on a 68 Chevy truck. He said he would buy the carrier if it fit. It fit and I sold it to him for what I paid for it. Both of us got lucky.
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