Rear Crank Seal Ring Replacement 560sl
 

I have oil leaking out of the bell housing. Looks like the rear seal is leaking. I can also see some tranny fluid. I am thinking about replacing the Rear Crankshaft Seal and the Front Tranny Seal. What do I need to know?
1986 560SL, Eng 117.967.

Hey guys I need your help. Can I get some help from you smart guys?

Dave

Have never replaced the tranny seal, though it should be pretty straight-forward (pull the converter off and extract the seal). The crankshaft seal is roughly the same thing, remove the flywheel/flex disc and extract the seal. The MB repair manual recommends that the housing for the seal not be removed from the block as the mating surfaces are precisely machined. But I took the chance and used a very thin coating of RTV silicone sealant when installing. You want to use very little as you don't want excess dried sealant breaking loose and getting into the engine, and into places such as the camshaft oilers. I would recommend not removing it if you can get by. Of course there are special tools for everything, but if you're careful, ordinary shop tools should work.

You will want to take some very fine (or even very worn) emery cloth to clean up the surface the seal rides on. This applies to the transmission too. If there is a groove in the crankshaft where the seal rides, there are repair seals available which move the lip of the seal to a different location so it does not ride in the groove.

Of course, to do all this you either need to remove the engine, transmission, or both together.

What you need to know is that I pulled my tranny thinking I would do the same only to find out it was a head gasket.

If it really is the seal it can be replace but requires a special tool. Or it can be fabricated on a lathe. Also there are special lip seals available if the crank has a ring worn in it that allow the lip to ride on a new portion of the crank.

For the transmission, some piece of pipe either PVC or steel will usually do the job as a seal installer.

John Roncallo

Thanks Special Tools
 

Thanks guys. Will I need the special tool to install the rear eng. seal? Can I make one.

Thnaks for all the help.

Dave
1986 560SL