Replace Rear Axle Bearings on Chevy Pickupsby Don Bowman
When rear axle bearings go bad they normally make a grinding or whining noise and occasionally leak oil onto the tire and brake assembly. Replacing the rear axle bearings is somewhat of a technical job. It is not that difficult with the proper tools but is not recommended for someone with very little mechanical experience. To do this job you will need the wheel bearings and the seals.
Jack the back of the truck up and support it with jack stands. Put the transmission in neutral. Remove both tires.
Remove the brake caliper and the caliper support by unbolting it. Remove the brake line, then stick a bolt in the end of the rubber brake line to keep fluid from draining out. Remove the brake rotor (just pull it off). In the event that the truck has rear drum brakes, simply pull the drum off. Put the drip pan under the axle housing rear cover. Remove the rear axle cover with a 13mm socket.
Rotate the carrier until the pinion pin side with the 7mm bolt is facing down. Line the pin up with the very edge of the opening in the axle housing so the 7mm bolt will just come out without contacting the housing. Remove the bolt holding the pinion pin in. Remove the pinion pin.
Push the drive axles in as far as they will go. Remove the C-clips from the axles through the center of the carrier. Use the needle nose pliers and just lift them off. Once they are off, pull both axles out of the housing and stand them up.
Reinstall the pinion pin so the spider gears do not turn and get out of alignment. Install the retaining bolt just enough to hold it in. Insert the slide hammer into the axle housing and remove the seal and axle bearing all at the same time.
Insert the new bearing using the old bearing to act as a buffer so that you do not damage the new bearing by hammering on it--line the new bearing up with its recess and place the old bearing on top and hammer it in. Install the new oil seal. Do the same to the other side.
Install both axles and push them in all the way until they contact the pinion pin. Remove the pinion pin. Install the C-clips on both axles and then pull the axles out as far as they will go so the C-clips do not fall off the axles. Install the pinion pin and the retaining bolt and tighten securely.
Clean off all of the RTV silicone from the axle housing cover. Use brake clean to be sure the surface is free of oil. Run a ¼-inch bead of RTV silicone around the complete circumference of the cover. Let it stand for ten to fifteen minutes until the RTV begins to skin over. It is ready when you can touch the RTV with your finger and it will not stick or come off. Install the rear cover and the 13 millimeter bolts and tighten them down.
Install the brakes and tires. Fill the housing with gear oil thru the plug on the top-side of the front of the axle housing near the pinion. Fill it up until the oil starts to come out then tighten the plug.