I have my 8.5" set up with new parts, BCA A-9 axle bearings and seals installed by a machine shop, brake hardware switched over from the old 8.2". Now I go to slide the axles in and bolt the retainer plate down and both axles have about 1/8-3/16" of "in and out" movement. Upon closer inspection, the seal is not in contact with the retainer plate with the bearing outer race landed in its collar. Thinking back, it seemed that the old barrel-type bearing that came off the axles may have been a bit wider than the new bearing, but I didn't think much of it at the time. the machine shop pitched it long ago, so no way to check now. I went by the parts shop today and looked at one of the chinese bearings, and it seems to be the same width as mine, but the outer race does not come off the bearing like it does on my new A-9's. Don't know if this makes any difference, and would hate to have to change the bearings again, but I'm stumped. anyone have any suggestions?
The bearing should be a closed bearing.....not the one you have which is a two piece unit. From your pics, looks like you have the wrong set-up. Contact Monzaz or oPh for an accurate solution and they will have the correct bearings.
bearings He has the correct bearing. A9 there are many designs for the A9 bearing taper barrel everyone seems to have a different way of making them...lol. I hope Roger can shed some light. .I have not run across a problem yet on the end play of any 8.5 buick rears. Been tring to help but If I can not touch it and examine it is kind of difficult to know the exact problem. Seems to have the correct bearing and seal. Maybe the inner axle tube is messed up? are both sides having too much end play? Jim
Yes, the play is the same on both sides. I am going to confirm that the seals are right. thinking about it, if the one-piece bearing is the same width, and the same seal is used, I still have room for movement, though it would not have the tendency to walk off the race like it appears to be doing now. As I understand it, the bearing should land out down on the step of the axle tube. then the seal takes up the remaining space and extends to the end of the tube where it contacts the retainer plate that holds it all snug and in compression. if so, then the width of the bearing plus seal must be greater than the tube step plus backing plate in order to contact the retainer. I am going to take a look at a Timken bearing today at the Zone and see if it's any wider.
Though some are slightly different in design, the A-9 bearings are all the same dimensionally. Since the outer race detached itself, now you have the axle & tapered bearing sliding down the taper of the outer race. That is causing axle to move in & out & up & down slightly. Could start over with another pair of A9 bearings. Also make sure the housing ends are free of built up varnish. When pressing on axle bearings, I like to just press on the bearing first, then ck end play. One has to be careful when seating the A9 bearing on the axle, the outer race will often pop off if not really careful with the press. Too much in & out axle play, one can shim between the 712146 seal & the axle retainer. Can either buy several thick service pkg 8.2 or 8.5 side shims & then they will need to be spot welded together then ground on with Dremel tool. Or, can do as one of my circletrack racer/car builders does & take an old pair of GM stamped steel axle retainers & carefully cut the centers out of them with Dremel cutoff wheels. Next, carefully clearance with Dremel diegrinder bits, then MIG weld these cupped inners into the depressed area of your stamped steel axle retainers. After welding, clean up the welds with Dremel tool grind. Object is to pick up an extra .125-.200 on the back side of the stamped steel retainers. Realize it's a PITA, but sometimes only way to get the axle end play to a minimum. Hope this helps. :3gears: Roger
I looked at the one-piece Timkens today, and as Roger stated, they are the same dimensions as the A-9, so no help there. Are you saying that these bearings are shot due to popping the race off? I think they came that way out of the box, if I remember right? Can I have the machine shop try to relocate the bearing and collar a little, or will that cause a future problem by breaking the press fit? should the bearing land out on the shoulder when it is pressed on? Looks like my choices are: If I can use the current bearings, I can try to shim it up from inside the retainer, or back to the machine shop with a new set.
I would get a new set of bearings, and start from scratch. i just had my 8.5 bolt-in axle rear rebuilt. I purchased all of my parts from Reider Racing Gears and Rears in Michigan. They are extremely knowledgable and they got me all of the right parts. As a result, everything seemed to go together perfectly. Maybe they can help you.
The tapered bearing fit being loose... won't be effected by the bearing press fit. The bearing will either be seated or not. Another way to solve the problem is to machine a spacer to go behind the bearing in the hsg-bore of the rearend. I'll ck if I have anything close. Early GM 8.5 side spacers are .170" thick, but the diam is too large. such a machined spacer between the bearing race & the hsg-bore would actually be the cleanest solution, one just needs access to a lathe to create such spacers. :3gears: Roger
Thanks, Roger. I thought about that too, but couldn't find anything greater than 1.5" OD at the hardware store. They were labeled "machine bushings" and looked like it would work if I could locate the right size. At this point, I am pretty much resigned to getting the Timken bearings and hauling it all back to the shop. Problem is, I don't know what to do different, since the dimensions will all be the same when it is all pressed together. Still open to suggestions... While I have the attention of the finest minds in the rear-end biz, I have taken some measurements for the new driveshaft and would like to bounce those off of you. My driveshaft with the 8.2" measures 55" from center to center of the u-joints. My measurement with the 8.5", weight on the axle, tranny yoke all the way in, is 54". If you allow 1.5" for travel, the new shaft is 52.5", 2.5" less than before. Seems like most of the posts here call for shortening 1-1.5". Is my measurement out of line? thanks, dewey
Just poking around here with the search function, I came across this thread that has a picture of what looks like the bearing that came off my axles. http://v8buick.com/showthread.php?t=66881&highlight=seal In the picture, it appears (hard to tell in a pic) that the seal is a little wider than my new National 2146 and looks like it has a metal ring around the edge that bears on the retainer. If this is a little wider, it might be enough to take up my extra length. anyone ever see a seal like this? I am going to grab the Timkens and head to the shop today. If I can find seals like this, I'll get them also, otherwise leave 'em as-is. BTW, the zone didn't have any bearings or seals that looked right in their computer lookup. had to give them the part # for the Timkens.
More .02 Dewey, As regards to the end play also check the flange straightness. I've seen flanges bent at the bolt ends when people try to "pull" the bearing and seal into the housing just by tightening up the bolts. Once it is bolted down tight the center of the flange is actually bowed out towards the axle causing the end play you're describing. Just another possibility. As for the shaft, slip the trans yoke in all the way and then pull it out 3/4in. to 1in. Then measure from the center of the trans yoke u-joint to the pinion yoke u-joint center (Where the straps sit flush) This will be your correct CL/CL measurement for your driveshaft. Hope this helps, Tim
Dewey, When shortening driveshafts for 8.5 A-body & F-body rear swaps, we've always shortenened between 7/8" & 1 1/8". Never needed to go more. If measuring, do it on a drive-on lift. Hanging or jacked up r/e will throw everything off. Local longtime auto store/machine shop shortened several dozen driveshafts for me for over 15 years... nearly all for 8.5 rear swaps. Only charged $22 to shorten, more if they r/r'ed u-joints. Wish they would have charged a little more... they finally went out of business & driveshaft specialist biz is quite a bit more Bearing dimensions... Ck'ed the link, & the pic is of an old original Hyatt (GM) A9 bearing. Have never ran across an aftermarket A9 that was of that design. Will measure the difference, but I doubt the origal Hyatt A9 is more than .05" wider than the replacements. On the axle seals, I've never ran across a "thick" version of the 712146. Would love to know of one. Heading to O'Reillys in little over an hour. Will ck what the '87+ 4.0 Jeep Cherokees use as an axle seal. The XJ series Cherokees also ran the A9 axle bearing. :3gears: Roger
thanks, Tim. Good idea to check both the flange and retainer and make sure they are both flat. I'm going to sit on this another day and see if I can make some sense of it before redoing all the bearings. would hate to do so then find myself back in the same boat again. As for the driveshaft, that one has me scratching my head as well. maybe I'll wait until the axles are done and the car is on the wheels and remeasure it. no need to get in a hurry now... thanks for the input. keep 'em coming. dewey
the latest... OK, went back to the shop and swapped in the Tinken bearings. these are exactly the same width as the BCA A-9, and, as expected, I still have the same movement (well maybe slightly less). at least it doesn't have the frightening tendency to ride down off the outer race since it's all one piece. I'm going to figure out a way to shim it in 1/8" from the outside.
Hey dewey. Been watching your thread. hoping you get it figured out. Did you get you new posi in? :beer
Hey, Phil. Yes, picked up a real nice posi and gearset from Monzaz (Jim M) and it's all ready to go. Just need to get this space-out problem sorted out, get it on the ground to get a good measurement for the shaft. Everything bolted right up to the car perfectly and looks like new! Thanks again for sourcing the rear and blasting it all for me. off to figure out a shim... How's your car coming along? dewey
Good to hear. I spoke with Jim Burek on Monday. It sounds as if my motor "350" is together however with the GS nationals coming up next week he will be attending the event. He said the motor will be on the dyno the following week. Cross your fingers for me. Hoping for mid 400hp numbers more if possible :TU: once I get my motor back I can finish assembly of my 72. :TU:
lookee here! Went to O'Reilly's and picked up a couple of the Taiwan seals. note the difference in the profile on the landing shoulder. I believe this difference would be enough to take up the slack. I wish the Zone had had these yesterday (or been able to find them in their parts lookup). It definitely stands taller than the National seal that is installed. Anyway, spent a couple of hours with the Dremel tool cutting the cheap seals in half to have about 1/8" thick shoulder. Slipped them over the axle between the retainer and the installed seal, with the shoulder against the shoulder of the installed seal and bolted it up. nice and tight, no play, and the retainers bolt down flush. I think it will work. What do you think?
Axle end play problems Dewey, Can you before you assemble the axles take an old axle bearing off the axle and push it into the housing end and see how far it presses into the housing axle end. I think your problem might be there. Have not had a chance to check alot your info out ...But I am pretty sure the alxe has a machine step inside the tube check to see if yours is worn or smashed flat or anything like that...Or may have been machined wrong from the get go. Can not totally remember the tube end real well but humor me. Jim
