Clutch actuation oil leak 77 R100/7

[michaellong63]

Did a few searches, to no availal. Recently had to correct a clutch actuation arm issue on my 77 R100/7. Was very careful to ensure parts went in correctly by manual. Now I have a very large leak from the tunnel. What do I need to search for to correct this issue? Thanks in advance!

 

[20774]

Is this the way parts went back in?

https://www.realoem.com/bmw/enUS/showparts?id=0304-EUR-03-1977-2474-BMW-R_100_7&diagId=21_0069

What seals the oil from getting to the outside is #6. Is it possible that it was nicked or cut? Also, be sure that the circlip #11 is installed securely. If it falls out and the pin falls out or dislodges, that can load up the bosses on the back of the transmission and break them off. The repair for that can be expensive.

 

[michaellong63]

Is this the way parts went back in?

https://www.realoem.com/bmw/enUS/showparts?id=0304-EUR-03-1977-2474-BMW-R_100_7&diagId=21_0069

What seals the oil from getting to the outside is #6. Is it possible that it was nicked or cut? Also, be sure that the circlip #11 is installed securely. If it falls out and the pin falls out or dislodges, that can load up the bosses on the back of the transmission and break them off. The repair for that can be expensive.

Thanks. Due to a failure of one of the bosses that holds the swingarm pin in place, I lost almost everything inside. The only piece not replaced inside was the rod (#1). The washer (#3), Needle Cage (#4), Piston (#5) and Gasket ring (#6) were all replaced. It was VERY difficult to get the piston in place as the gasket kept wanting to prevent installation, so I am guessing it got distorted during installation. Also replaced pin with updated version that has a larger head at top, along with the accompanying circlip for lower retention. Any hints at how to prevent issues during installation?

 

[20774]

When you say "swingarm pin" bosses, are you indicating the two supports that holds pin #12 in place? I'm wondering if/when that pin came loose and the supports were damaged, that might have damaged the bore that the piston #5 runs in. Seems like a long shot, though. Generally, though, all of those items (#3-#6) should slide in relatively easily. Obviously, it's tough to work back there. With the gasket ring on the piston, it might take some persuasion to insert into the aft end of the bore, but I wouldn't resort to sharp tools to do that...maybe just fingernails.

If after inserting all of the parts and it continues to leak, you'll probably have to pull out the transmission to see what's wrong. Before doing that, and maybe before reinserting the new parts, see if you can get a mirror in there and take a look at any issues such as scratches, etc.

If one of the bosses failed, how was it repaired? It would be important to get the orientation of the holes correct so that the actuating lever is pushing in-line with the piston that is inside the bore.

 

[michaellong63]

RE re

Will pull the piston back out later today and perform another inspection. Even though it is new, ordered another from Max as it seems really sensitive to possible tearing. Can't hurt to have a spare. Have had the transmission out for the initial work and thoroughly inspected it then. As for the repair, the holes were not disturbed in the repair (same diameter, location, etc.). Thanks a bunch. Gave me some things to look for.