Well, the weather is finally looking up a bit over here, so it's back to the Buick. Not entirely out of free will, as two weeks ago the left rear brake pipe burst, being completely rusted, so started working on getting some new ones on the rear axle this weekend. (wanted to start sooner, if it weren't for an unattentive driver sideswiping me on my bicycle, so I had to recover from the worst of that. Yep, not the happiest camper right now...) On pulling the right rear wheel I found two things though: Whoever put on those American Racing rims was probably very drunk, or indifferent, or stupid. There were four different types of lug nut used and although the rims have thick hubs and spacers were used for inside clearance the wheel studs were still the original ones... The nuts are hanging on for dear life (MY dear life) with only a couple of turns... Yikes. So, I need longer studs. Fast, I'm not driving it anymore with this knowledge. I've been searching the web for them but I can only find the stock replacements. Does anyone know of longer studs for an EW? Front and rear? The second thing I noticed when I pulled off the drum to check the brake, is that the brake was completely smeared with oil and/or grease. No really, completely. I'm surprised it braked even a little. The oil/grease seems to originate from the wheel bearing, so it could be it was either overpacked or the packed with the wrong grease. But I was wondering, and this may seem a silly question but this my first real wheel drive car, is the entire rear axle oil filled? If so, is it sealed at the wheel? Because that seal might very well have failed. Any help is appreciated, thanks! Oh and it's quite late, but: happy new year!
Yes the entire rear axle is filled with gear oil and lubracates the axle bearings, so that seal and pollibly the bearing is shot. Some rear axles come out by four nuts accessed through hole on axle shaft. Some you need to pull rear diff cover and remove spider gears so axle will push in and remove C clips then axle will slide out.
GM used 7/16 studs for the longest time. Later on they switched to 12 mm. The wheels should work with 7/16 inch, 1/2 inch, or 12 mm studs as long as you have the correct lug nut. I'm assuming the seats for the lug nuts have a 60 degree taper. Find the length you need, press out the old studs, and press in the new ones.
I've got a catalog of Raybestos brake parts and wheel studs, and the corresponding application guide. They've come in real handy for the custom disc brake projects on my trailers. So I figured if I looked up the specs on the studs on your wagon, I could look for one with the same specs but just longer at the thread area. But Rockauto lists 2 different studs for a 76 Buick Estate wagon. (The specs for Raybestos match those of the Dorman.) Both are 1/2-20 and of similar length but one has a .620 diameter knurl and one has a .535 diameter knurl. Very non-interchangeable. Unless you can find something more definite, you'd have to press one out to see what studs are in it to start with. Then add whatever extra length you need and see what's available with the same thread and knurl but longer. Either find a good parts store that is willing to take the time to get you what you need. Or if you can measure the knurl with a caliper and check the rest of it, I can look through my book and see what I can find based on the extra length you need. My book shows both too. Now I think about it, the ones with the longer and larger knurl probably press into the thick front rotors, and the ones with the shorter and smaller knurl probably press into the rear hubs. How much extra length do you need?
Update Thanks for the replies, everyone. In the meantime I found there are soooo many variables regarding rear axles I (bravely, at least it felt that way) pulled the axleshafts and popped some studs and found all the info I needed. The seal was indeed very, very done on the passenger side. And I'm going to have to drill out the stud holes to be able to fit readily available longer studs. I also found something strange: second seals on the inside of the wheel bearings... Don't know what they were thinking! So in retrospect it's a good thing that left rear brake pipe burst, otherwise I wouldn't know about all this until it was probably too late. I'm kinda glad I took my Buick off the hands of the previous owner... But hey, now I'm replacing the brake pipes, a wheel cylinder (couldn't get the nipple out, it was fused to the cylinder with rust) the C-clips, bearings, seals and studs, so it'll be a pretty pristine rear axle soon About the axle, I found it's a 31-spline, 8.75", 12-bolt C-clip axle, probably 3.08 ratio. I've read many good things about 12-bolt axles regarding strength, so that's a plus. The downside is if I want new axle shafts they'll have to be custom made, costing twice as much. It was the first time I ever opened up a diff, so besides all the worries it was also a great learning experience, getting to know my car better!
Then that axle was set to have rear wheel bearings packed in grease. I have removed those inner seals and let the axle bearing ride in gear oil. But if you look at your diff cover you'll probably notice the level of gear oil/bottom of hole lower then a diff cover that allows gear oil to lube rear wheel axle bearings. Change out to higher diff fill hole and done. Usually the axle tubes from gear set to bearings are dirty from vent and lack of fluid flowing to and from axle bearing so while apart flush out tubes if going this route.
Darn, that might just be true :confused: Is that a setup anyone uses? I couldn't find any reference to this on the internet. The general consensus seems to be that the axle bearings ride in gear oil on GM axles. Also I haven't found any 'inner seals' available. If the fill hole is indeed too low, can't I just rotate the diff cover 180 degrees? Because I wouldn't know where to get another diff cover ASAP. And how would I flush the tubes?
I doubt you could just rotate the diff cover and still bolt up. Look at where the fill hole is? It may very well be high enough to lube axle wheel bearings. I found this years ago on 4x4 with Dana 44 axles. Not only were there tin covers but thick covers, fronts were very low fill hole because no axle bearings and rear was low or high depending on bearing lube by oil or grease. 12 bolt would not be hard to find an aftermarket cover, look them up and see where fill hole is compared to yours. Worst case is you fill the axle and jack up one side and pour in another quart... but I would rather have correct location. Flushing the tubes is a pain, you'd have to remove the carrier/ring gear or just pump some solvent through holes where axles go into carrier and pump some solvent through, make a long handle brush etc... kinda home made deal. I usually have an diff out on jackstands when I do this much work... if it has a vent in middle of axle housing you'll usually see rust on one axle. Also make sure this vent is clean. If it is clogged up then pressure builds when axle get's hot and causes leaks.
Glad you got the wheel studs figured out. The ones I used on my camper disc brake conversion came from a 1960's Chevy work truck. They were in stock but I'd have ordered them if I had to, they were the perfect match. You said something about a second seal and I was thinking of the extra seal they put behind GM FWD hubs which are similar to GM RWD hubs. But Eagle has good advice, he knows a lot more about these axles than I ever would.
Ugh, just when I thought I got it all figured out... This is basically what my diff cover looks like, only it has a fill plug that has it's bottom about at the top of the bolts at the low point of the scallops: http://www.jdrace.com/Rear_ID/rears 011.jpg It seems symmetrical on the horizontal plane, so it should be possible to rotate it 180 degrees. But then I'd risk overfilling and that would lead to excess foaming of the oil and what not, which can't be good. How high should a gear-oil-lubed-axle-bearings-axle have it's fill plug? I gathered gear oil expands quite a lot when warmed up, so the fill plug position I described might be the correct one... Now that I think about it, judging by the amount of gear oil I found in my right rear brake, even after letting my Buick sit for a while it seems the gear oil reaches the bearings just fine. But then again I don't know if it was overfilled or not. Argh... just goes to show how incredibly frustrating things can get if you don't know the history of the vehicle...... I'm putting on the new brake pipes and wheel cylinder this weekend, I'll make sure to check that axle vent by the way.
Got brakes? Yes I do, once again. I also found the axle to be well-vented. There's a big ol' plastic plug on top that has a diameter the size of Texas. I'm going to craft a little filter for that, don't need no dirt in there. I triple checked my shop manual and found everything else to be as it came out of the factory. So the fill plug is where it should be and the bearings (are supposed to) run in gear oil. So it's official: whoever worked on that axle didn't know what they were doing. I'm receiving the parts next week (thanks David!), I'll finish my home-made bearing puller and next weekend the Buick will be doing burnouts! If I ever made burnouts though, which I don't. I mean, the rear tires are 150 euros a pop plus it's a non-posi diff, who in their right mind would be doing burnouts? Still, some people do... Happy easter!
Success! Well, after some test driving I think I can call it a success. No leaks, no bearing noise, no diff noise and the rear wheels are finally fastened properly! I've been smiling a lot What I missed at first is that the previous owner installed some (very) el-cheapo repair bearings. That explains the inner seal, and the complete failure of the seals.... Those proved a pain to remove by the way, but in the end it all worked out. Thanks everyone for your help!
