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Leaky Axle Seal Diagnosis on my 1993 Suburban

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Leaky Axle Seal Diagnosis on my 1993 Suburban

Truck Trend Truck Trend
Administrator | Posts: 4666 | Joined: 02/07
Posted: 12/30/08
06:13 PM

I pulled off the brake drum on my 1993 Suburban to inspect the brake shoes and noticed the dust from brake-shoe wear was moist and oily. I saw no actual fluid, so the leak must have just started or is very slight. The fluid didn't appear to come from the brake cylinder, and the brake-fluid reservoir is at the proper level. I plan to clean the brakes thoroughly and then watch for a fluid leak in the next week. If I find no brake-fluid leak, I'll assume the axle's seal is leaking. Will replacing the axle's outbound seal require special tools? Does the seal need to be pressed in and/or out? Can the outbound seal be replaced with the axle in place (thus not having to open the differential's access plate and pulling the C-clips to remove the axle)? Is there a need to remove the entire axle assembly and differential from the vehicle?


A: Yes, you can pry out the old axle seals with a big screwdriver or pry bar, and the correct-size seal-driver tool should be used to install the new seals. But if you're careful, the seals can be installed by gently tapping them in with a hammer. No, the seals don't need to be installed with a hydraulic press, just slowly tapped straight into the axle housing. No, the axle shaft goes through the seal so it has to be removed. And no, again, there's no need to remove the entire rear axle assembly. If the brake's wheel cylinders are dry and everything else is wet, the axle seal is leaking and must be replaced. A technician can usually smell the difference between brake fluid and gear oil. Assuming we're working on a half-ton Suburban with an 8.5-inch rear axle, you'll have to pull the differential cover, remove the differential pinion shaft lock screw, extract the shaft, push the axle inward, and remove the C-lock from the button end of the axle. Then remove the axle, replace the seal, reverse the procedure, and fill it up with SAE 80W-90 GL-5 gear oil. If it sounds involved, have it done at a good repair shop. Remember, it's silly not to replace both axle seals while you're in there, and always replace any brake linings that have been contaminated with fluid other than water.

If you have a technical question regarding your pickup, SUV, or van, feel free to contact Alex Steele, a master technician with the National Institute for Automotive Service Excellence. Send a letter to him in care of Truck Trend Garage, 6420 Wilshire Blvd., Los Angeles, CA 90048, or e-mail us at

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