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Help with blown axle seal

6438 Views 54 Replies 10 Participants Last post by  VManganese
Hi friends!

Inspecting tires for an upcoming trip, noticed mucho "oil" had sprayed onto the inner side of one of the rear tires - figured it was a blown brake cylinder, since I had to slam on the brakes for a pickup and horsetrailer that pulled right in front of the 95 Caprice wagon. But upon investigation, and sniffing, realized it was 90weight or whatever the pumpkin oil is, all over everything and the axle seal leaking like crazy.

Never done this job before (have done the distributor remove, clean, replace, heater core flush, spark plugs, water pump, etc.) so would appreciate inside info to help me with this job. What a mess! Brake shoes, drum, everything coated in 90wt. Luckily I have new brake shoes already. Got the new seals, and figure once I do one side, I might as well do the other, before I forget how to do it.


Veronica (and of course this happens as winter approaches in Eastern Oregon, and me without even a concrete slab to work on)
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Your axle is probably worn out. I had to replace both axles on my 91OCC a few years ago for the same symptom. I suspect it is the right side of the car, because that is always the first one to wear out. Be prepared to buy another axle, as well as the other components mentioned. You may not get the studs with a new axle. You can use your old ones over. Tap them out gently with a nut on the end, and you can tap them into the new axle. Rock Auto has the axle (both are the same), and there is a 5% discount code on the forum in the vendor's section.

The job is not as hard as it may appear. It is just messy, and smelly because of the axle oil. It is also a PITA because you must lay under the car if you do not have a lift. You should check the other side in case it is starting to leak.

A piece of cardboard works for under the car. It is nice, because you can slide on it easily, and you do not get splinters.
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Small things to add
What ever side you are currently working on, jack that side of the axle up a couple inches.
It will heĺp with the mess because the oil in the axle tube will wander back to the center and not be waiting to pour out as you pull the seal and bearing.
Take a real good look down the tubes.
Often there is some horrible crap in there that should be wiped out
Pack grease around the garter spring on the seal.
This will stop the spring from popping off when you hammer in the seal

When topping up the fluid, jack one side up,wait a couple minutes , lower.
Do the same to the other side.
Then recheck the level

Also, if you have a limited slip and are adding friction modifier, squirt it in the vent, rather than try and get it in the fill hole, way easier.
He will be draining the fluid to get to the C clips, so he does not have to worry about much fluid draining out of the tubes.

When refilling the rear, if you have an LSD, put the correct amount of additive in, then fill the rear with lube. It will be easier if you have a small length of tubing to allow the bottle to upend, and empty completely, because the fill hole is on the side of the housing.
Wow, thanks! Never even thought about the need to replace the axle. This car as 340,000 miles on it. Probably time.

Rotate the differential to get the hex bolt out: can I do this with one wheel on the ground? I figured I needed both off the ground.

Where's the best place to support things - can I put stands under the axle housing/tube whatever it's called?

I actually don't have a problem squirming around on the ground: I keep large pieces of cardboard, and I have a yoga mat. Sometimes I nap under the car, in the summer, when my husband thinks I'm working. Usually the only way I can take a break...LOL The biggest problem is that I don't have a good level place to put jacks and jackstands, so I have to be uber careful not to endanger myself or the car by unsafe supports.

Yes I don't like the smell of 90wt and now the inside of the wagon reeks of it because I threw the brake drum in there before cleaning it.

I have new brake shoes so was going to replace them, since the old ones, though they have a lot of lining left, are soaked, totally soaked, with oil.. Yuck! Once I get everything cleaned I will feel a lot better about the job.

Gonna keep reading now. Y'all are a girl's best friend! Too bad we can't get together for a beer afterwards.

The seal itself is probably not all that bad...maybe worn on the top from the axle being off center in the bearing. At 340K the axle is probably only 90% of its original diameter at the bearing. The right axle is usually worse than the left.

You should put one jackstand on each side under the frame to give you enough room to work. You can put a piece or two of plywood under each jackstand to stabilize them. Lifting the car by the frame will allow the rear to drop, giving you more room to get at the parts, and refill it. If you put fluid in through the vent, you can not measure the level unless you take the side plug out also. Although it may be easier to put fluid in through the vent, if you do not have to remove the vent you will not have to try to install it blind. To properly fill the rear, you fill it until the fluid is even with the fill/check plug on the side.

If you feel really adventurous, you can replace the pinion seal while you have it apart. The FSM has instructions, and it is not all that difficult. When reinstalling the pinion nut, tighten it to the mark you put on it, then an eighth of a turn.
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Holy crap, at 60 bucks apiece, kind of a no brainer for a stock car.
Disclamer, never used these myself
I have a pair in my 91 OCC, and they haven't broken yet. One was made in China and the other in India. I bought them before I knew of Rock Auto, and they cost me a lot more. I do not think the axles come with bearings and seals, but you can check before you buy them.
My bearing puller was a long 3/4 inch steel tube. I put it in one side and tapped the bearing out the other. My differential was out, and it may not have worked with the differential in the housing without curving the tube.

It gives you a good feeling to accomplish something that most people will not even attempt.

The struts are probably easier than the axles. You do need an alignment after replacing them. The lower bolts allow for some camber adjustment, and the toe will change.
The Moser axles are far superior to the ones at I have the specs to order them. The ones on are made in India, or China. Moser are made in the US.
You do not need to buy a lot of tools. You can "borrow" the big ones from Autozone, a hammer and a medium size set of sockets. You need new bearings and seals.
Don't forget to add 10bolt 8.5" GM to the "Type of Rear End" line so they know it needs c-clip grooves.

They know that it is for a GM 8.5.
Same as the sedan axles. If you decide to get new gears, make sure you get set that accepts a reluctor, and a correct reluctor for the ratio.
I have a supply of HVAC knobs @ $20 shipped. I can offer a discount for more than one. I suggest carefully wrapping the shank of the knob with thread and add a drop of C/A to keep them from breaking.

The oil amount is probably the main culprit, or you used the wrong gasket for the cover, blocking the lube holes on the case. I use silicone to seal mine. Get some Moser axles this time. And, yes clean the housing. A magnet on a stick will grab the small chips.

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That was supposed to be C/A.
Cyanoacrilate glue, AKA super glue.
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