Everyone, what are you using for new bearings and seals in this unit? I was looking on the JD RAce forum and saw where he was having trouble with bad bearings http://forum.jdrace.com/viewtopic.php?f=16&t=562 I personally do the 12 bolt chevy rear even with c-clips we would use disc brakes in the back and that will be a c-clip elim effect so really c-clip rear will not be any issues with disc brakes. PLUS c-clip axles just seal really well and do not cause leak issues like the bolt in axles do. WE have had BIG trouble with the 8.5 rears not sealing good at the axle shafts. NEW or Used axles The bearings are garbage in the market for that axle system these days. Were taking the rest of the bolt in axle 8.5 rears and chopping the ends off and installing c-clip ends to solve this leak issue. tired of the calls...
I am still finding some National seals that are the correct width. Most of these companies are converting to one seal,to simplify production,and are making a width in between the two. There is also a variance of how deep the axle tube was bored. If it’s on the deeper side,you will need a wider seal,or a shim that is placed into the tube before installing the axle. What I do is mic the depth of the bore,withnyhe backing plate. Then mic the overall width of the bearing and seal together. If the bore depth is greater,use a shim. Otherwise once everything is installed the cone will unseat from the race,and the weight of the car pushes down on the housing,the shaft pulls up on the seal,creating a gap on the bottom side of the seal,which then lets oil leak out.
Brian, What is the most correct seal thickness? Is it .490". There have been numerous threads over the last decade I think of incorrect seals. .375" is the incorrect seal width if I remember correctly. This leads to excess end play problems/leaks. You build rears. We need some clarity on this. What is the average measurement of bore depth, and how does that correlate to needed seal thickness for the 2146/712146 seals?
The 2146 is the thinner and incorrect one. The 712146 was .490,but they seem to be coming out at .460”.
Just to clarify is the .490 the overall thickness or just to the flange (does that include the flange. A friend of mine has some on the shelf, .470 to the flange, .490 including I could probably make some shims if needed
There still might be stock floating around of TIMKIN made in Mexico boxes. The Tawain seals are Junk set9 they are .470 or thinner. Look for OLD STOCK. Or if you can find old stock axle bearing NON TAPERED bearings then it will not matter at all what the seal thickness is as there will be NO up down play only in and out end play like a c-clip axle does. So we all though c-clip axles were bad...lol. Whos the joke on now??? lol. If you use disc brakes on the back pf any c-clip axle rear ...THAT IS AS good as a c-clip eliminator. Do not fear the c-clip rears. That is why we still use them to this day. JD Race Jim
Interesting view on the caliper bracket and or caliper itself holding the axle in if it broke.......never thought about it that way b4 but so true
I wonder if they make a bearing seal combo like this for the 71/72 8.5? https://www.hotrod.com/articles/10-bolt-bearing-upgrade/
They don't, that setup is for when the bearing eats through the harder outer axle there and starts making lots of noise....you can move the bearing and seal to a new location rather than buy new axle..........its a bandaid not a great fix......the bearings in a semi float setup do carrier a decent vertical load.......now your bearing is just few thousand press fit
WORST ITEM EVER DESIGNED...LOL. If your axle is compromised and they are talking about wanting stronger 10 bolt ....They are defeating the whole purpose. You are using axles that should be replaced. The bearing saver was NEVER, never designed to save a HOT ROD driven car axle. Maybe a A-B go to work and back car . It is to save money for a reason...CAUSE you do not HAVE ANY. If you have a Fast Hot Rod, you need to buy a NEW upgrade better alloy axle shaft, with a NEW axle bearing and seal and then you solve the problem and add strength to the rear. THAT is a totally misleading article IT IS NOT AN UPGRADE by any means. It is a Low grade fix to keep your car running enough to get it to the JUNK YARD. Please guys do not use these Bearing savers. Fix it correctly for your own safety sake . Buy an axle shaft and get the correct bearing and seal installed. JD Race Jim
I was just looking at some timken 2146 seals, they are measuring .375, way too thin unless you use a big spacer. Measuring and comparing is the only way to be sure you'll not have a problem.
How about the 712146 seal? They should be .490", correct? This says .470" thickness, https://www.rockauto.com/en/moreinf...x43SH5QhkAqfj1lDAUQJkJiE4s9bTGaNwHecZksMFpg==
The newer ones are coming out at .470”. There are some coming with some Yukon packages that are anorexic thin. They would need a shim,spacer,or no backing plate,which could work in some disc brake applications,but I prefer to use a thick one with everything.
Another thought... I guess you can machine the end of your axle flange tube also...Grind...Seems archaic....BUT could solve the distance factor on the seal. the backing plate then sits on that surface and should put more pressure to the seal. If you did convert to disc brake you can make the spacer that is in the disc brake kit any thickness you want which again would help solve the distance that needs to be removed for proper seal pressure in the housing tube end. I tried shims...They just are very had to get machined and so thin...And on the outside they do not stay put....Tough deal there. I hate to say it but I have been cutting the tube ends off and making these rears c-clip. Plus it trues the housing up, 30 spline axles are off the shelf part.... Solves bunches of headaches for me. Only thing now is they are all gone...LOL... Our junk yards here in Ohio are done. ALL front wheel drive nothing old anymore. Jim JD Race
oh and the 2146 seals were used in the 1970 (typed in wrong) 1971 1972 were thicker 712146 Pontiac a body and f-body late 69 and late 1969 & 1970 olds and Buick a-body the depth in the tube ledge is shallower than the 71- 1976 era. ??? why they changed i have NO IDEA? I have parted out so many of these BIA rears and had so many axles on the shelf...YOU can just glance at the axle bearing and seal and KNOW which ones are from which year era. I have been unloading the BIA 8.5 71 72 on ebay in the past two years. I had so many from the 30 spline conversion done over the years.... Now when i hear BIA 71 72 8.5 i just get a headache.... UGH I use to be so into them. Now i cringe. When Timkin caved In, I literally was deflated. I called them and could not get a good answer to why they switch to .470 when GM has it specified at .490. We all know it was Money and they just did not sell enough to care. Jim JD Race
