AmpleUnicorn88

I have a 9 bolt G92 3.45 rear end from my 1987 Iroc. It is the original rear end and as far as I have discovered or know, it hasn't been modified. I took it out last weekend, and I will explain why now, before getting into my concerns/questions.

I bought this Iroc on new years eve, for $600. It was complete minus the transmission and the front bumper and hood, otherwise complete. It had sat for a few years, the PO said he thinks it was about 2 years it sat before parked, but based on the condition, I would say much longer. the Odometer read something low, and the mileage counter on the overhead console stopped before 100K miles, and I am not sure if it was driven much after that or not. I haven't open the diff cover yet, because I am nervous what I will find. I only turned the rear end to push it onto the trailer and off when towing it to my house, and then when I first got it home and turn the wheels to check to see if the posi was still working. Both wheels turned in unison in the same direction, so it appears on that test alone, it is still functioning. I know that isn't the best test to feel confident, that is simply where I am currently at. I dropped the rear end last week to clean all the grime and rust off of it, and replace the brakes and lines, and change the fluid. So far, I have't run into any physical issues like a dented tube or bent hub, it's just a fair bit of corrosion. I have seen rear ends corroded like this before that were still being driven, so I am not too worried about the structural integrity of the rear end, and I have already cleared most of the corrosion off of it in preparation for painting it.

My concern is the axles and the bearings. I am almost positive I am going to get a unanimous yes if I ask should I replace the wheel bearings, just because it sat for who knows how many years, but I am sort of wondering how that even works. I read a few different things online, here and other places that it appears that the hub is part of the axle on these. I am used to the hub being able to separate, and I was going to replace the hubs on these, but it seems like the bearing is by the differential and the entire axle has to slide out to replace it. I'm assuming there is some sort of bolt or clip or something that holds the axle into the housing, but I am unsure from the different write ups I have seen on other sites. The hubs aren't damaged, they just have a little bit of rust on them, but I have seen a lot of rusty hubs in my days, so that doesn't really concern me.

Any suggestions on this would be greatly appreciated. I am kind of nervous about pulling the axle since I have never opened up a rear diff before. But i figured with having the rear end completely out of the car, this would be the best time to do this.

chazman

iTrader: (4)

Maybe you're over thinking it? There is no evidence that there is something wrong with it.

big gear head

At the very least you need to remove the cover and change the oil. I've seen many rear ends that sat for a few years that had a lot of rust on the ring gear. To remove the axles you need to remove the 4 bolts that hold the axle in at the end of the axle tube. These bolts also hold the brake caliper brackets on.

AmpleUnicorn88

At this point I am just assuming everything has the potential to be bad, because it sat for so long. The good news is it sat in Arizona so the undercarriage is rust free and the only rust I found was the rear end and the block/heads from water getting in them from rain.

I was thinking since the rear is off if it was not that hard to do and it's a good chance the bearings are bad, then this would be the time to do it instead of getting it all back together just to have to take it apart again. I am no expert here so if people tell me I'm over reacting on here, I'd believe them.haha

AmpleUnicorn88

I am definitely going to be doing that. And I removed the 4 bolts on one side so far, but I don't see any way that the hub separates from the axle so I just assumed it attached inside the diff.

big gear head

The axle is one piece. It has a pressed on axle bearing that may be tight in the housing end. It might take some force to remove it after the bolts are removed.

AmpleUnicorn88

So there is nothing actually bolted in the housing to hold the axle to the housing? I thought I read on a few different sites that there is a bolt and a clip that hold it in and then the bearing sits around the inner part of the axle at the housing.

big gear head

The Borg Warner 9 bolt rear end uses a pressed on axle bearing and the brake caliper bracket to hold the axle in the housing. When the 4 bolts that hold the brake caliper bracket on the housing are removed then the axle, along with the caliper bracket, can be pulled out of the housing. The GM 10 bolt rear end is not made this way. It uses a c clip on the inner end of the axle to hold it in.

AmpleUnicorn88

I'm going to have to take a look again. When I looked at it last, I took those 4 bolts out of the back of the backing plate on the hub end, and that seemed to just make those brackets loose and dangle. If it's pressed in, is the way to remove it smacking it with a hammer on the back of the hub until is slides out? Installation the reverse of removeal?

big gear head

It usually isn't real tight. You shouldn't have to hit it very hard. Don't damage the axle when you hit it.

sofakingdom

iTrader: (1)

Bearings don't go bad from sitting, unless they get water in them.

OTOH it hardly ever hurts to change em.

If you decide to, make sure you have all the replacement parts in you hands, BEFORE tearing it down; both bearings, and both seals.

jmd

iTrader: (4)

A slide hammer attachment (with room for 3 studs to be pulled) is safer than using a hammer to tap it out.

The spline end of the axle may be some level of stuck in the side gears of the diff.