I had replaced the rear crankshaft seal, oil pump cover, bolts and oil pump cover o-ring. I also replaced the camshaft seal as it was leaking. You can read how I did that here.
- 11 BMW R75/5 Remove-Install Flywheel, Replace Rear Main Seal, Oil Pump Cover & Cover O-Ring
- 11 BMW R75/5 Replace Cam Shaft Seal
This is the parts list.
|11 14 1 337 654||Front Crankshaft Seal||1|
Remove the Stator
I replaced the alternator brushes which requires removing the stator. You can read about how to remove the stator here.
Remove the Rotor
When I purchased the brushes from Euro Motoelectrics, I also picked up a hardened bolt to remove the alternator rotor from the crankshaft.
With the stator removed, the rotor is exposed.
It is secured to the crankshaft with an Allan bolt and is pressed onto the tapered nose of the crankshaft. Since my engine was out of the frame, I installed the tranmission and put it into first gear to provide some extra drag so I could loosen the alternator bolt.
Then I removed the bolt and washer.
I threaded the rotor removal bolt and had to block the rotor from turning to get the rotor to back off from the tapered crankshaft nose. I used a 1 inch steel strap carefully inserted between the steel casing avoiding contact with the coil windings.
It popped off the crankshaft exposing the front main crankshaft seal.
I had recently purchased a Lisle shaft seal puller, #584030, and used it to remove the old seal.
The hook slips beside the shaft and the extends under the shoulder of the seal.
There is an adjustable pivot bar so it can be placed on the housing and then you lever the seal out of the hole.
I heated the engine housing with a heat gun to make it easier to remove the seal. It popped out the seal in quickly.
Installing the New Front Crankshaft Seal
I used metal polish to clean the tapered nose of the crankshaft and the tapered bore in the rotor. Then I used brake cleaner to get any oil off them.
I put a little oil on the outside of the new seal and then heated the engine casing around the seal bore.
I pushed the seal into the hole evenly and used a 30 mm deep socket and a rubber mallet to tap it home.
Installing the Rotor
I put the rotor back on the crankshaft nose and threaded the alternator bolt into the rotor. I used the 1 inch metal bar to carefully brace the rotor and tightened the rotor bolt to 17 FOOT/pounds.
Installing the Stator Housing
You can see how I installed the stator housing in the write-up on replacing the alternator brushes.
I put the timing cover back on the engine and then polished it. Here is the engine ready for installation in the frame.
I am glad to have found your site I am just starting on a wonderful 73 R/75. Please, your process for polishing the engine.
Thanks in advance,
That sounds like a worthwhile project to sink your teeth into. The R75/5 holds a special place in my heart when I ride it.
I posted a write-up on all my refinishing techniques here:
I hope this helps.
Mr. Reams , Thanks so much for the very concise and clear instructions on replacing the front Crankshaft seal on the R75 . I would assume this is the same tool set required for performing this job on a 1985 r80rt. What would be the cost that a shop ( I know a private mechanic) would charge to perform this seal replacement??
I don’t know what a shop would charge to do that work. The tools work on a 1985.
I hope that helps.
Hi Mr. Reams,
First of all thanks for the great content.
I believe I have over-tightened the Stator bolt that goes into the crankshaft nose…and it has been stripped. In you opinion is it feasible to take it to a shop and have them re-tap the hole? Ideally I do not want to have the crank replaced as the engine was just fully rebuilt. Do you have any suggestions?
BTW, you mean the rotor bolt as the alternator rotor attaches to the front nose of the crankshaft.
I haven’t had that problem before, so I am not aware of solutions. I suppose it maybe possible to install a heli-coil insert to repair the hole. That said, drilling and tapping the hole for the heli-coil requires the hole to be dead center and square with the centerline of the crankshaft. That is very precise work. It may require the crankshaft to be removed, but I don’t know that for certain.
I’m very sorry you had this problem.