Sealing the final drive by Richard Cook
Dan and Fred convinced me that the gasket had to go in my rear drive. It was three thicknesses on my Chang and shrunk as the oil soaked into it. This left the bolts loose and removed a fair portion of my oil one afternoon. Next winter I'll be trying to get burned on oil off the muffler. 1)   First jack up the bike and put down the rear stand. 2)   Next remove the two nuts and washers that hold the rear portion of the fender down, pull out on the brackets, and lift the fender. Tie or bungee the fender up out of your way. I keep a bungee in the Chang so I used that. Watch your head working around the fender brackets; don't ask me how I know this. 3)   I pulled the drain plug and drained the rear end oil into the pan, leave the pan under it because housings often drain a bit more when opened. 4)   Now it is time to loosen the axle lock bolt at the rear of the left shock. I like to use the punch in the picture to control a bike axle. Once the lock bolt is loose you should be able to spin the axle to arrange the castellated nut on the sidecar side to get at the cotter pin. I like to pull cotters with side cutters. Straighten the legs, spin the axle, and use the side cutter as leverage to pull the pin. The nut is usually not very tight after that. 5)   With the nut off you can support the wheel and use a punch or any lever that fits the axle hole for pulling the axle. 6)   On BMWs I was taught to look for a spacer on the axle between the wheel and the rear drive. Sure enough mine had the washer you can see in the picture with the axle. That little washer with the 18mm hole in the middle is my spacer. Those spacers are to line up the wheel so nothing rubs so don't lose it. 7)   With the wheel out of the way the rear drive is quite open to work on. There are six nuts, flat washers, and lock washers on mine. Loosen them evenly to get the drive separated about as far as mine is in the picture. The two on the front are miserable to work on, I can just get the end of an open end wrench on the lower one and turn it with another wrench. These are in for some modification when I have to tear the drive down for anything serious. 8)   I then cut out the old gasket with an exacto and a razor knife, and cleaned the area carefully to remove all old gasket and sealer. Time spent here is well worth it and crawl around to see the entire area. 9)   Since my housing is plated my plan to use silicone sealer (plated surfaces cause blow out with silicone) was off and a board member had recommended the product called the "Right Stuff" I used that. It acts like regular Permatex as far as being incredibly sticky, applies like whipped cream, and give you six minutes to get it together and cleaned up. Have all your nuts and washers in order, Locktite ready with top off, wrenches laid out, and be ready to work fast. Pull all nuts down evenly making sure the ones in the front hidden behind the shock are on first as there would be no room to install them if the housing is close together. If you don't know how to operate a whipped cream can then this job may be a bit much for you. Six minutes later you are ready to add oil but I let it cure overnight. 10)   I was taught to lightly lube BMW axles and splines and I use high temp disc bearing grease. I'm sure many products work. 11)  Since I want to add the oil when the bike is level now is the time to install the wheel. Do any brake work first, note blue label on these shoes that Dan recommended. Using the punch to control the axle I hold the wheel up and slide in the axle till it just stick out of the wheel. Then you can insert the spacer on the axle or on BMWS some folks hold them into the spline on the hub with heavy grease. Then navigate the axle into the housing and out the other side. I just take the play out of the axle with the nut and insert the cotter pin with it lined up as close as possible. Then I turn the axle with the punch to bend the legs with the side cutters. 12)   Drop the bike back on the ground and add oil to the rear end. I have a modified funnel for adding and a fitting on the end of my suck gun for taking fluid out. Since everyone tells you the seal will blow out if you fill further than the lowest threads; and I have not made a breather for the axle yet, I made sure I did not over fill. If you look in the picture you will see a bag of BMW sealing washers available at any BMW car dealer. They are the same size as the Chang washers. I used new washers and a dab of liquid Teflon on the drain plug. Since the filler will be open now and then I did not Teflon it. Don't use Teflon tape on alloy housings by the way, as folks have cracked some expensive stuff doing that. I filled up with, horror of horrors, Redline racing multi-grade so we'll see if all my seals fall out soon. 13)   Drop the fender and Locktite the nuts and you are ready for a test ride. This job was about three hours of work I'd say. Less if you had all the materials ready and did not run to two auto parts stores looking for the Gasket maker material. Less still if you knew what you were doing. So far it has survived the first test run with no leaks but time will tell.