8.5 in rearend
- Thread starter Billy1979malibu
- Start date
here's the next best thing. https://www.moserengineering.com/12-bolt-housing-axle-package.item
Jeez, that's some really low turning resistance. Per the CSM, IIRC, your pinion bearing running preload should be 10-15 lbs/in on used bearings (20-25 lbs/in on new bearings). And that's just pinion bearing preload with nothing else in it.
I would suggest you do this before tackling this thing (unless you're absolutely sure of your skills): Buy a couple or three crush sleeves before setting out on this venture. Because likely you'll do this on a Saturday night, after all the stores are closed and can't buy junk until maybe Monday or at least until the next day. And because of Murphy's Law. If you overtighten them you're done and will need to replace it, or if you need to install/remove any shims for backlash adjustments. The sleeves are GM p/n 1234726 superseded to 12479162 for your 8.5. You can get aftermarket equivalents at Advance Auto Parts, etc., for around 3 bucks each or so. You can always get rid of them later to some other poor sap that is rebuilding an 8.5 setup. Or, you could get one of those crush sleeve eliminators. You just would use pinion depth shims at the gear end to adjust pinion depth, then tighten down to correct preload.
Everything you need, as far as specs, is in the chassis service manual. AFAIK, there's no specific GM service manual for the 8.5. The straps/bolts should fit 7.5 or 8.5. As far as chasing threads. I make it a habit to ALWAYS chase threads on re-used stuff, and even new if it looks like it could use it, or if it's going on a critical part like in the engine.
I've personally always shied away from those bolt/strap kits like that. May hold up just fine, but GM OEM stuff is still available, so I'd go with that for final install. Something about those bright shiny zinc coated straps look a bit lacking in quality is all. It almost looks like they stopped the stamping machine a bit too soon on those straps. NO idea about the bolts.
For those looking for the GM OEM type stuff, U-joint strap bolts are GM p/n 3387348, superseded to 14018700. They're 5/16"-24 x 1-11/32" long. List for $2.88 each. Comes in a box of 20 (list $57.60 per box), but dealers usually have these in stock so you should be able to get them individually as needed.
The U-joint retainers (straps) are GM p/n 7846740 superseded to 23107858. Still available from GM. A tad pricey at $19.19 list price, each, but they seem beefier than the kit straps.
So if you get the parts from GM, you're looking at over $50 individual pieces. I can see how that might get people to buy those cheaper kits. But you can scrounge around and probably find the same part numbers for a bit less.
I would suggest you do this before tackling this thing (unless you're absolutely sure of your skills): Buy a couple or three crush sleeves before setting out on this venture. Because likely you'll do this on a Saturday night, after all the stores are closed and can't buy junk until maybe Monday or at least until the next day. And because of Murphy's Law. If you overtighten them you're done and will need to replace it, or if you need to install/remove any shims for backlash adjustments. The sleeves are GM p/n 1234726 superseded to 12479162 for your 8.5. You can get aftermarket equivalents at Advance Auto Parts, etc., for around 3 bucks each or so. You can always get rid of them later to some other poor sap that is rebuilding an 8.5 setup. Or, you could get one of those crush sleeve eliminators. You just would use pinion depth shims at the gear end to adjust pinion depth, then tighten down to correct preload.
Everything you need, as far as specs, is in the chassis service manual. AFAIK, there's no specific GM service manual for the 8.5. The straps/bolts should fit 7.5 or 8.5. As far as chasing threads. I make it a habit to ALWAYS chase threads on re-used stuff, and even new if it looks like it could use it, or if it's going on a critical part like in the engine.
I've personally always shied away from those bolt/strap kits like that. May hold up just fine, but GM OEM stuff is still available, so I'd go with that for final install. Something about those bright shiny zinc coated straps look a bit lacking in quality is all. It almost looks like they stopped the stamping machine a bit too soon on those straps. NO idea about the bolts.
For those looking for the GM OEM type stuff, U-joint strap bolts are GM p/n 3387348, superseded to 14018700. They're 5/16"-24 x 1-11/32" long. List for $2.88 each. Comes in a box of 20 (list $57.60 per box), but dealers usually have these in stock so you should be able to get them individually as needed.
The U-joint retainers (straps) are GM p/n 7846740 superseded to 23107858. Still available from GM. A tad pricey at $19.19 list price, each, but they seem beefier than the kit straps.
So if you get the parts from GM, you're looking at over $50 individual pieces. I can see how that might get people to buy those cheaper kits. But you can scrounge around and probably find the same part numbers for a bit less.
Thank you very much for your insights. Yes, I was surprised by the nil turning resistance of the original pinion with carrier installed. I did buy GM straps and bolts for u-joint. I have to do the u-joints too; will need driveshaft resized. There is a parts car down the street ready to donate spare shaft. I'm considering replacing this cast yoke on the diff, since the threads were so ornery, and since I upgraded to 30 spline axels. The gear kit I bought from Quick Performance comes with one crush sleeve AND the solid spacer/shim 'upgrade' for the pinion preload... I was hoping to use the crush sleeve and pat myself on the back.
Nevertheless, even with the nil turning resistance, I appear to have 0.0075" backlash in the old setup (measured 3 locations). Tonight I'll take it apart... Fun stuff. By the time I'm old and blind I'll have done a thing or two.
Looks like this bearing race for the carrier on the passenger side is wiped.
I just figured out that I need a press to get these bearings on/off the carriers. I knew I need to press for the pinion but I didn't expect to need one for the carrier bearings.
I just figured out that I need a press to get these bearings on/off the carriers. I knew I need to press for the pinion but I didn't expect to need one for the carrier bearings.
And usually you'll find that you destroy the bearings getting them off the carrier. So if you every want to save them, don't plan on it.
Side bearings are 9420095, superseded to 23312178. Or equivalent aftermarket. Fits 7.5 or 8.5 or 9.00. Ain't cheap. List price is 79.04 each side.
Two 0095's on ebay right now for less than 20 bucks each.
Or you can just buy one of those installation kits. Just make sure they're good bearings and seals.
Two 0095's on ebay right now for less than 20 bucks each.
Or you can just buy one of those installation kits. Just make sure they're good bearings and seals.
Part of the kit. Thanks, though. It's all new to me; first time rebuilding one.
I thought I was going to be able to knock out these pinion races with a brass drift, but it has become clear that will not work. I can't really get a tool in there to measure the front race. Does anybody have a recommendation for a socket size or driver tool that they used? If I have to use a press, that's fine... I need one for the install anyhow. I'm still thinking I can get a giant socket on it and knock it out with a dead blow.... but I don't work on Abrams Tanks so I don't have a socket that size.
Attachments
You get a punch and work your way around it. That's not a very big socket in the scheme of things..just saying.
