I need to pick your brains. I've completely rebuilt my GM 8.5" BOP 10 bolt in my '71 Buick GS. New customo Moser 30 spline axles, TrueTrac diff, gear, seals, bearing... everything. I drove the car around today and there is a small pool of oil, AGAIN, on the inside of the wheel on the drivers side. I don't know what else to do. Here's one thing I noticed when reinstalling the axles. When I installed the axle on the passenger side (no leaks) the axle seal was tight in the axle tube. I applied a thin layer of oil but it still needed a few light taps to fully seat the axle. When I installed the axle on the drivers side (was leaking before rebuild and still is again) I noticed the axle slid right in without much pressure on the seal. Two questions: Assuming somehow the inside of the axle tube is worn (larger): Is it possible to insert some sort of sleeve into a worn axle tube? Are there slightly larger seals that could help? What other ideas do you have? What else am I missing? This is getting really frustrating. I didn't mind doing the full rebuild because it needed it after all these years and miles but now it's still leaking slightly. HELP!!!
Take some accurate measurements on the seal HEIGHT. I had one pressed on that was about .020" less in height which also caused a loose axle (in and out) causing a small leak. Altho thats an Olds type "O" differential, with bolt in axles, compression on the assembly is critical... ws
There are two different axle seals for the 8.5 rear end with bolt in axles. One style is thinner than the other and is not pressed in properly when the axle is installed. This can cause leaks and also excessive axle end play. Larry posted about this a while back and it included pictures showing the differences in the seals.
I had the "correct" part number installed on my axle, and when pulled into place had an extra .081" (guestimate) end play in the axle (thrust). I had to have the shop order the other seal and he ate the bearing. Once installed. The total end play was about .001-.002". The seal and bearing is also an "exact" fit it the tube. Bone up on yer French LOL... The gap shown on the axle bearing pic is due to the skinnier seal at .081". ws
Yes, the axle seals can be a problem. If you have the wrong seal, it is thinner. that also results in excessive axle end play. Pull the wheel on each side and check the end play. My guess is the leaking side has more end play. The INCORRECT seal is .375" wide, the CORRECT seal is .490" wide. The correct seal # is 712146. Lots of them get boxed wrong. https://www.yukongear.com/productdetails.aspx?ProdID=4145
timken axle seal , had same problem on a 8.5 timken took care of problem other seals are not thick enough
Here's an update: Jim (monzaz) and I had a good long chat tonight. With 0.170" drivers and 0.161" passenger side end play! (in-out movement of axle) we concluded this. The Wilwood disc caliper retainer plate is about 1/8" thicker than the stock drum brake backer plate was. So now my axle retainer plate is pushing and pushing on that caliper retainer plate sandwiched between the axle housing and the retainer plate but it's not even touching the seal inside. That seal, and bearing, aren't getting pushed deep enough into the axle tube, hence the excessive play. I still can't explain how the passenger side DIDN'T leak?! Wilwood has a special BOP c-shaped retainer plate with a curled inner edge that pushed directly on the front surface of the seal. It's part# 250-13508 but it's hard to see. Hopefully I can get Wilwood to ship it directly to the hotel in Colorado so I can still race this weekend. I'll reinstall everything on the trailer in the hotel parking lot. Not my first rodeo! Wish me luck! THANKS AGAIN JIM! Your knowledge, and patience , are amazing!
I orded 2 of these so called .490 seals from yukon. They spec out at .440 no where near what the say. The set of 712146 in it now are .470. It drives fine but do have some bearung end play. Cars on jack stands until I can figure out the right seat up.
Yes its terrible. Looking like options are make shims or source set of used good axles. It remains to be seen if a bit of excessive end play will be a issue. Without proper preload no way to get around bearing lash being not loading race. 712146 are .20 shy. Yukon should be ashamed advertising .490. .50 off . Going back to summit!
Chinaman loses out to the JAP guys. Either tech up or dumb down. ws https://www.google.com/search?sxsrf...hUKEwiLv8_IgrLqAhVaK80KHd6FDwkQ4dUDCAk&uact=5
Actually, I owe this one to Monzaz... After showing him indicator readings he told me right there what the deal was. Two different seal numbers and the motorparts guy grabbed the first book number part off the shelf and installed it. The machinist there shouldve MIC'd the old one and didnt, so the guy ate the job. I paid for the new seal altho the owner said to not worry about it. IIRC, the store bought a new bearing as well. Parts I pay for; a faux pas is on them! I'd still be waiting for a "decision" from rot-auto. Had this back together the same day. Hmmm ws
