every now and then I used to get this rumble in the drivers rear wheel when I make a right turn. Saturday night at a local show, it got worse. I had the worst in mind thinking it was the gears, but my father seems to think its the wheel bearing. Any ideas?
Im pretty sure my 72 GS 350 Conv automatic with AC has the orginal rear end. But how do I verify it so I buy the right bearings and seals? How many bolts should there be on the cover? any other characteristics that can be used to identify it?
The 8.5 A-body rear will use straps & 7/16" headed bolts to attach the u-joint. Earlier 10 bolts all used U-bolts along with nuts & lockwashers on the pinion flange. Doing this job, best to remove the wheel & brake drum & pull the axle. The most common axle used in the '71-72 8.5 A-body rears has 3 nickle or so sized holes in the axle flange. One can access the 4 nuts retaining the axle by carefully turning the axle, then using a 9/16" socket through either of the two slightly smaller holes in the axle flange. When all 4 nuts have been removed, place a large pickle fork or other prybar between the wheel cylinder & the axle flange, & bump the axle outboards. Axle should pop out. Most common '71-72 8.5 A-body rear axle bearing should be an A9, & the axle seal will be a National 712146. IF the axle flange has 4 holes large holes in the axle flange, you MIGHT have an A10 axle bearing 8.5 A-body rear. That is not always the case, as towards the end of '72 production, there were "4 hole" tapered bearing axles being used along with A9 bearings in the less common appearing 8.5 A-body housing. Removing & installing new bearings will require the use of a press, a bearing seperator plate, & a dremel cutoff wheel, along with a hammer & chisel to remove the bearing retainer. One must be careful when pressing on A9 or A10 axle bearings. Board user deweylittle had a good topic on here early last week about problems he was having with A9 bearings that were not extra carefully installed. :3gears: Roger
Sounds like something I'll be having a shop to. I dont have the press and have never done it before. Thanks for the info!
Hey Curtis, If the bearings are bad make sure to clean out the axle tubes and clean/drain out the center of as much of the metal shavings as possible. Providing the axle brgs. are good, and you have a L/S (posi) then upon refill of gear lube be sure to add GM L/S additive to help with any clutch "chatter" that could also be a cause of your cars symptoms. But normally "chatter" occurs when turning right or left after driving straight for awhile so the bearing may be your problem. Good luck with it...Tim
Curtis, when you get your axle off, measure the width of the combined seal and bearing and get parts that are the same aggregate width. The outer edge of the seal must be in contact with the retainer plate or you will have the movement I have. I don't know why my axle has a little wider shoulder that the bearing and seal ride in, but it seems to. I could have avoided a lot of headaches if I had thought to check all the dimensions first, rather than just relying on part numbers. Anyway, make sure you get parts that match dimensionally what you are removing. In my case, the Taiwan seal has a little longer shoulder than that of the National and looks like it will solve the problem. Since it's so much fun, you might consider changing both sides, flushing out the tubes and housing and fill 'er back up. Who knows, the other bearing could go next week... lessons learned the hard way, dewey ou:
