1976 R75/6 Shifter

There is no oil seal for the allen screw securing the shifter? I replaced the shaft seal but it looked like oil may also have been weeping past the allen screw head.

Thanks

Not according to the fiche; just #9 on this diagram:

http://www.realoem.com/bmw/showparts.do?model=0292&mospid=51887&btnr=23_0256&hg=23&fg=11

Here's the allen bolt #5:

http://www.realoem.com/bmw/showparts.do?model=0292&mospid=51887&btnr=23_0269&hg=23&fg=41

I've never had this apart or out, so I don't know how it could leak around the bolt. Unless yours wasn't snug or there was some kind of burr in there??

Thanks. Back together it goes!

Thanks,

Chip

cseltz said:

I replaced the shaft seal but it looked like oil may also have been weeping past the allen screw head.

Thanks

Click to expand...

Oil was weeping/seeping around the bolt because the shaft seal was leaking.

Shifter seals

There are two seals around the shifter, both can be changed by tilting the bike at an angle and removing the shifter and then extracting the two seals. After the seals are replaced, the allen should be tight. If it is loose, transmission fluid will indeed leak from around the allen head bolt.

DaveM
1975 R90S
2001 R1100RT

interesting...my R60/6 (owned since new) has only one shift shaft seal. Mine leaked shortly after installing new seals for years, until finally, an old airhead mechanic at the BMW shop informed me that the seal should not be driven home to the base of the boss, but only halfway, being careful not to insert it at an angle. That was about 10 years ago, and it hasn't leaked since. I have heard of folks putting two seals in there, but mine has always had only one seal.

I cannot see where a second seal would go. I did drive the seal all the way in. If it leaks, I will try that idea (with a new seal). I cannot see how the shaft seal can have any effect on oil getting to or past the allen bolt so I am ass of u and me ing that tightening the bolt is creating a "metal to metal" seal. We'll see.
Additional comments / ideas are appreciated.

Thanks,

Chip

Do what you can to keep the gear oil from leaking out around the seal. I've never done the use of 2 seals, but if you do and the leak stops, excellent. If you have tried all the different ways and it still leaks, try this. I think the transmission is rated to run 800cc's, drain and add 700 cc's. This will put the oil level just below the shifter seal and the oil leaking and weeping should stop. 700 cc's is more than enough to keep the transmission operating properly. I can't stand oily stinking gear oil on my riding boots, and this has worked for me.

There is only one seal shown as part #9 in the first microfiche photo. This is normally the only problem with these leaking and it can be replaced with the transmission in the bike. The recessed area the seal goes into is rather deep so be careful to not drive the new seal in deeper than needed.

In that same first photo there is a part #15. It is called the "olive" or the "pumpkin" I forget which. The diagram drawing is a pretty good idea of what it looks like. The part # is 23111233383. It is shown sitting off to the side so it's not clear where this part goes in the transmission. It is called "suspension". This part is sometimes the reason for a shifter leak that is difficult to fix with a new seal. If worn it allows the shifter to wobble too much, I think. I'm not sure if this part can be replaced with the trans in the bike or the trans has to be opened up.

Also notice that the bolt holding the shifter in is not a generic bolt with an 07 part number. It is a transmission part specifically and has a part number that starts with 23. When nuts and bolts have 07 part numbers they can sometimes be found at a local hardware store or at least from another source. The transmission group is #23 and a part # that starts with a 23 is not a generic part.

Also, polish the shift shaft with an emory cloth before re-installing. There could be a burr (or something) on the shiftshaft that could be scratching up the seal contact area.

I am pretty sure the old seal was leaking because it was old. I have a new seal in place, I thoroughly cleaned the contact area between the head of the allen bolt and the shift leaver (even lapped them a bit) and put them back together. I seemed odd to me that there was no "o" ring or the like to positively seal oil from migrating through the bolt hole in the shift leaver and weep past the bolt head but that appears to be the case. We'll see how it works out. Thanks for all the feedback.

Chip