Front crank seal?

[Oldbmwmc]

I have an oil leak in the front of my engine. The oil appears to come out of the engine from behind the alternator. The small compartment with the points in it has quite a bit of oil in it, but the bike starts without much of a problem. I need to fix this leak. How do I proceed from this point?

I have seen several articles about replaceing the rear engine seal, but nothing about a front seal.

Please help!

[sgborgstrom]

Working from memory here...

The procedure is the same as if one were to replace the timing chain....which you might as well do if you are this deep in the engine (mileage depending of course)

The points, alternator/rotor and diode board come off first. This leaves you with the timing chain cover, it has a bunch of bolts holding it on, a seal for the cam and one for the crankshaft (this is the one that is leaking in your case) I think there might be a gasket back in there too. Remove cover, replace BOTH seals and any other gaskets etc re-assemble.

I use Clymer, Haynes and a BMW manual for cross referencing stuff.


Steve

[Weasel]

That sounds about like what I should do I guess. I noticed some oil in the same spot about 20 yrs ago, but it hasn't affected anything, starting or running, so that's the way it still is. It's not gushing out, of course...but it's always there.

[flash412]

Remove the front cover. Remove the battery ground. Remove the wires from the alternator stator. Remove the three bolts that hold the stator. Take a small screwdriver or needlenose pliers and while pulling on the brush wire, pull the spring back until you can move it SLIGHTLY to the side. Withdraw the brush. Repeat for the other brush. CAREFULLY and EVENLY lever the stator up. Do not lever on the windings. You only have to get it up about 1/4" before it pops loose.

Remove the rotor bolt. (You might need to smack the wrench to get the bolt to break loose.) Get an alternator puller bolt[1] and screw it into the rotor until it pops off.

Take a small drill bit, maybe 3/32" or so and drill a hole in the seal at 6 o'clock. Screw a sheetrock or sheet metal screw into the hole. YANK the seal out with a pair if vise grips.

Get a deep-well socket (or piece of pipe) that fits OVER the end of the crank and is the same diameter (or smaller) than the O.D. of the replacement seal. Put some motor oil on the seal, all over. Press the seal into place with your fingers. Use the socket and a hammer and slowly, gently, EVENLY tap it into place so that it is flush with the timing cover.

Reassemble in reverse order.

Go ride. Pop the front cover back off after 50 miles or so to make sure you didn't screw it up.

[1] An alternator bolt can be purchased from a BMW dealer, borrowed from a friend or made from a common bolt and used in conjunction with the rotor bolt (or equivalent). What you do is find the largest HARD bolt that will slip PAST the threads in the rotor. You cut it off just shorter than the threaded portion in the rotor. Stick it in there. Then take a HARD bolt with the same thread diameter and pitch as the rotor bolt (which can be used, but it isn't recommended) and screw it in there. When it starts getting difficult to turn, whack it on the head with a hammer straight toward the rear main seal. Keep turning it. It WILL pop the rotor off. DISCLAIMER: This is a shadet-tree mechanic trick. You are on your own if you follow this advice. I have had a (soft) bolt-shaft in the crank bend. If that happens you MUST keep turning the bolt until the rotor pops off. With the rotor off, the bend bit can easily be retrieved from the crank end.