[leejoy]

Help

I will be upgrading the rearend of my 72 Nova starting November. Amongst the numerous upgrades and tasks include removing and replacing the rear axle bearings and seals. I've never done this. I'm sure it's easy but...... I've seen specialty tools like slide hammers and punches, etc used to remove and press in the new bearings.

Can somebody help me - describe the process please. What are the tricks. I will be removing the entire axle housing from the vehicle. Send some pictures if you have them. I usually rent tools from Advance Auto Parts or AutoZone. they both rent all the popular auto service tools - I'm sure they' ll have whatever I need right?

I have a 10-bolt 8.5" housing - thanks.

Lee

[poncho62]

There were 2 types of GM axles....those with the pressed on bearings and the ones with the full floating bearings. I am not sure which you have.

Press on type....You undo the 4 bolts nolding the backing plate to the housing and pull the axle....Like you said a slide hammer may be needed. A piece of chain bolted to the stud works just as well. Bearings are then pressed off and on.

The full floating type has to have "C" clips removed in the rear end to pull the axles. A bolt and a pin has to be removed that retain the "C" clips. You have to be careful because this pin also hold the spider gears in place. The bearings can then be removed and replaced in the ends of the axles.

[Henry Highrise]

The Nova should have the floating type. You will have to remove the cover from the rear end and remove the cross pin and c-clips that Poncho mentioned...then you can remove the axles.

[jimfulco]

Put the axle on jack stands and support the front of the center section. Put a drain pan under the center and remove the bottom center cover bolt. It may or may not drain from the bolt hole. If not, remove the cover, leaving the top 3 bolts in, but loose. Pry the bottom of the cover out a little so the oil can drain out. Don't get in your hair or it'll stink for a week. Finish removing the cover and let if drip for a while.

Look for the finger-diameter pinion shaft that runs through the differential carrier (the thing the ring gear is bolted to). At one end of it is the retaining bolt, which runs perpendicular to the shaft through one end. Remove the bolt. It's threaded just under the head, with a smooth shaft extending past the threads for an inch or two.

If you're lucky, the shaft will try to drop out by itself. It may need some persuasion. Try not to turn the axles or carrier too much after the shaft starts coming out, or the spider gears (pinion gears) will slide out of the carrier and you'll pull your stinky hair out trying to get them back in right. Once it's out, push the axles inward far enough so you can remove the C-clips from the inner end. A "magnet-on-a-stick" tool is real handy about now. Once the C-clips are off the axles, you can slide them out.

Use a slide-hammer puller to remove the wheel bearings & seals. They can be a bear if they've been in there for a while, so don't be afraid to bang hard.

Look at the machined surface on each axle where the bearing rides. If it's grooved about as wide as a roller bearing is long (3/8"-1/2"), you probably need to get new axles. I've heard there are aftermarket bearings that ride on an unmolested part of the axle, but I wouldn't use them in a high-performance car.

[leejoy]

Originally Posted by jimfulco

Put the axle on jack stands and support the front of the center section. Put a drain pan under the center and remove the bottom center cover bolt. It may or may not drain from the bolt hole. If not, remove the cover, leaving the top 3 bolts in, but loose. Pry the bottom of the cover out a little so the oil can drain out. Don't get in your hair or it'll stink for a week. Finish removing the cover and let if drip for a while.

Look for the finger-diameter pinion shaft that runs through the differential carrier (the thing the ring gear is bolted to). At one end of it is the retaining bolt, which runs perpendicular to the shaft through one end. Remove the bolt. It's threaded just under the head, with a smooth shaft extending past the threads for an inch or two.

If you're lucky, the shaft will try to drop out by itself. It may need some persuasion. Try not to turn the axles or carrier too much after the shaft starts coming out, or the spider gears (pinion gears) will slide out of the carrier and you'll pull your stinky hair out trying to get them back in right. Once it's out, push the axles inward far enough so you can remove the C-clips from the inner end. A "magnet-on-a-stick" tool is real handy about now. Once the C-clips are off the axles, you can slide them out.

Use a slide-hammer puller to remove the wheel bearings & seals. They can be a bear if they've been in there for a while, so don't be afraid to bang hard.

Look at the machined surface on each axle where the bearing rides. If it's grooved about as wide as a roller bearing is long (3/8"-1/2"), you probably need to get new axles. I've heard there are aftermarket bearings that ride on an unmolested part of the axle, but I wouldn't use them in a high-performance car.

thanks buddy.

and yes, I will be pulling the whole housing out anyway and installing new axles, carrier, ring&pinion etc. these are the original (34 year old) bearings so I imagine they will be tough to get out. I'm just not sure what type of slide-hammer tool to rent. I'll see what they have. Also, what about installing the new bearings? How is that done. How deep to I press/punch them into the axle housing?

[onovakind67]

If you've got the differential out you can drive the axle bearings out from the opposite side with a long pipe. I use electrical conduit from Home Depot.

[leejoy]

Originally Posted by onovakind67

If you've got the differential out you can drive the axle bearings out from the opposite side with a long pipe. I use electrical conduit from Home Depot.

WOW - DUH!!!!

excellent idea. why didnt I think of that. I've got plenty of steel pipe and conduit around. that's what I'll do. thanks.

what about installing new ones? How far do I "pound" them in?

[poncho62]

They will borrom out in the pocket that they sit it. You will see it once you get the old ones out.

[jimfulco]

They make a bearing driver tool, but I just put a chunk of wood between the bearing and a 2# hammer and drive it in that way.

Same with the seal, just put a little sealer on the inside of the axle tube and drive it in lightly until it's flush with the end. Put a little gear lube on the bearings and on the seal surface before you install the axles.

Before you put the rear end back in the car, put it on stands nose down and put some lube in through the back side. For an 8.5" GM, put about 1.5 quarts in, then add the Posi additive if you're using it. Total capacity is around 2 quarts, so you won't over-fill it. Don't forget to top it off through the filler plug after it's installed.