Toyota Maintenance: Replacing a Rear Axle Sea
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Author: Joe Micciche - June, 2002
|The axleshaft and backing plate: I had some cleaning up to do.|
When a rear axle seal goes bad, it's typically noticeable by gear oil leaking all over a rear wheel, and it may get into the brake drum and reduce rear brake feel. In my case, I was fortunate to notice it while doing some other work under the truck.
One of the more common causes of Toyota rear axle seal failure is a plugged differential breather. When the stock breather is unable to vent the diff, the internal pressure will find relief somewhere in the system: usually at the axle seal. So, if you have a leaking seal, be sure to check the breather for proper operation. Or better yet, replace it with an extended breather.
There can be other causes of seal failure, among them a worn wheel bearing or a bent housing or axle shaft. In this case, my wheel bearing was shot at 90,000 miles. (Due to having the bearing removed and a new one pressed on at a machine shop, that operation is not covered here.)
|The brake assembly and axle/backing plate prior to removal.||The e-brake cable is off, and the hydraulic line is "gravity bleeding".|
To replace a rear seal, the rear axle should be placed securely on jackstands, and the tire removed. Place a drain pan under the end of the tube to catch any gear oil which may drip. Once the tire is off the vehicle, remove the retaining pin from the emergency brake lever mechanism at the backing plate and move the cable out of the way. Then, the hydraulic brake line can be removed from the backing plate. If you don't have a flare tool, remember the line fitting nut is soft and subject to rounding off, so be cautious.
Next, the axle shaft is removed from the housing by loosening the four 14mm hex-head bolts from behind the backing plate. Once the bolts are off, grasp the backing plate and carefully pull the entire brake and axle assembly from the housing.
|The old seal is removed and the seal surface cleaned.|
With the brake/axle assembly out of the way, the old seal can be pulled from the housing end. Using your favorite seal puller, pop the old one out.
Once you have the old seal out, check the seal surface and clean, if necessary. Also, clean any old gasket material from the axle flange, assuring none gets in to the axle tube.
|The new seal is greased and seated, ready to be driven in.|
The new seal should be prepared with a coat of grease on its outer surface, to help drive it in smoothly. Place the new seal into the axle end, and carefully drive it in. For this seal, I found the front hub 2 1/8" socket with a towel on the end was the perfect size to drive the new seal. Once the seal is seated, coat the inner surface with grease as well.
With the new seal in place, clean up the brake and backing plate assembly. Saturation of gear oil on the various parts will determine the cleanup effort, but at a minimum a healthy application of brake cleaner should be a good start. The brake shoes and drum, along with all of the brake actuation mechanism, should be scrutinized.
With everything cleaned up, place a new gasket on the axle flange, or use your preferred gasket-maker. Very carefully guide the axleshaft back into the housing, taking care not to ride it in on your new seal (which can deform the seal instantly).
|The front hub socket, padded with a towel, is perfect for driving in a rear axle seal.|
The backing plate bolts should be torqued down to 51 ft. lbs. The emergency brake cable is reattached, and the brake line threaded into the backing plate. At this point, the rear brakes are bled, the differential oil level is checked and topped off, and the repair is complete.