white90 Posted October 19, 2007 Posted October 19, 2007 If you have oil leaking from the hand brake drum, then the output seal has started to leak - either just through age and normal wear or because the bearing behind it has failed and movement of the shaft is allowing oil to leak out. There's a seperate thread for replacing the bearing, and this one is how to replace just the seal. If the seal has failed it will either come out of the lip of the drum or here. Jack up and support the drivers side rear wheel and chock the wheels on the opposite side. Put the gearbox in drive and apply the handbrake as hard as possible. Use a 14mm spanner or a propshaft tool and undo the nuts that holds the rear prop to the transfer case. Then tie the prop out of the way. Undo the screw that holds the drum to the drive flange. The 30mm nyloc nut that holds the drive flange in place is very tight and considerable leverage is needed to undo it. A breaker bar is normally needed. Just slacken the nut for now. Release the hand brake and then undo the adjuster on the back of the brake backplate with a 12mm spanner. The drum will then lift away - exposing the handbrake assembly and drive flange. Place a suitable container under the transfer case, remove the drain plug with a 17mm spanner/socket and allow the oil to drain out, then replace the drain plug. Action shot! It's usual for there to be a small amount of swarf on the magnet in the drain plug. As long as no chunks of metal fall out, then don't worry about this. Remove the nut, washer, and fibre washer and remove the drive flange. Inspect the seal land of the flange for grooves created by the lip of the seal. If there is a groove then fitting a new seal may not cure the leak and the flange will have to be replaced as well. This one is fine. The seal has a protective cover over it - lever it off carefully, taking care not to damage it. The old seal can now be seen. Carefully lever it out with an old screwdriver or similar tool. Be careful not to damage the alloy housing of the transfer case. Put a layer of grease on the outside edge of the new seal. Then drift it in squarely with a suitable tool - I have used a hub nut box spanner here. Be careful not to damage the raised lip of the seal. The seal has to go inside the housing until it butts up against the bearing outer track. If it's not in far enough the flange will damage the seal failry quickly and it will then leak. Tap the seal cover back on. Apply a layer of grease to the drive flange. Locate the flange on the shaft splines and then press/knock it back on. The felt washer sits in a recess - when the nut is tightened the washer is compressed and thus stops oil from weeping out up the shaft splines. Replace the washer and nut - hand tighten for now. Replace the brake drum and it's retaining screw, adjust the handbrake back up and pull it on tight. Using a breaker bar or similar form of leverage - tighten the flange nut. Replace the propshaft. The filler plug on the transfer case is also a level plug, so providing that the vehicle is on a reasonably level surface, fill with EP80/90 oil until it starts to dribble back out of the hole. A 1/2" drive ratchet is the right size to remove the plug. Replace the plug and lower the vehicle back to the ground. Les.
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