The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: AP914 on August 03, 2011, 11:12:56 AM
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The rear axle is leaking fluid all over the ground. It wasn't leaking from the owner I bought from who lives at a substantial higher altitude. Difference of about 3000 ft. What do I need to do and what do I need to buy? I don't have the manuals yet, they're being shipped to me with other extras.
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Chances are good, that the rear brake camshaft is leaking, there are at least 2 o-rings on the shaft .
Not a complicated job .
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Either what Bob says or,
1) Check the final drive "oil level" bolt. Run your finger on the case under the bolt. There should be a crush washer used with the small bolt. However, for me...
The threads within the drive case can be easily stripped by someone who's a bit ham-fisted. My '81 came to me with, at no additional charge, a stripped and heli-coil repaired case. Grrrr
I tried multiple times using crush washers but to no avail. A thin rivulet of gear oil continued to wend its sticky way to the bottom of the drive case where it dripped onto the rear tire and shop floor.
Ultimately, I did a ghetto fix by using a hard plastic/rubber compound faucet washer from Ace Hardware and BMW Supply. Snugged the bolt down. Snug only. No more leaks.
2) I also replaced the small O-rings and exterior felt washer on the brake cam shaft. That stopped even more dino juice.
3) Finally, I broke down and replaced the honkin' big oil seal in the final drive case. It lives under the Cardan cover. Need a new paper gasket for that job.
I did find a tiny nick on the hardened final drive surface near the oil seal's contact point- how it got there is a PO's story I'm guessing.
By a slight reposition of the big oil seal, I got away from the nick and the rear end of the '81 no longer wears Adult Pampers.
4) This is a stretch but the domed filler plug on top of the final drive is a vent to atmosphere. Remove the filler bolt/vent and confirm it's not plugged up. Right, Sue? ;)
Run dino oil rather than synthetic. The synthetic oils seem to create oil leaks in the old Airheads. It's not just oil, It's liquid engineering. -Castrol. Yeah, right.
Final thought... Confirm the final drive is not overfilled. A wee bit under does no harm. Also avoid parking the bike tail down slope as that will artificially raise the oil level in the final drive while you're parked... drip, drip, drip
Glad you made it back, APGirl.
Monte
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The first thing to do is to completely clean and degrease the final drive and rear wheel. Ride it and dust the suspected area with talcum powder. Wherever there is oil or grease the talc will stick and turn dark and you can see exactly where it's coming from AND going to...
Once you know what's leaking then it can be decided what is needed to fix it.
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Just discovered a stripped filler bolt on the final drive case of my 84. Hadn't noticed any leaks but went to do a fluid check prior to a trip and Mr. Wildknits (who is a mechanic and is helping me learn how to do these things on my bike) had a bad feeling as he was removing the bolt.
The fluid check morphed into an oil change once we got a look at the gear box oil. Yuck!
Came online tonight to see what words of wisdom I could pick up for fixing this stripped bolt (actually the threads in the case). Am hearing a lot about helicoils.
For the short-term the bike is up on the stand and won't be going on vacation with us tomorrow (so sad!).
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I just had to deal with this about a year ago .
Same scenario, first fluid change on a new to me bike .
I removed the final drive took it to an independent BMW bike shop and had the threads repaired with a threaded insert .
You don't have many options here.
Special tooling is required to get the final drive disassembled .
http://www.cycleworks.net/index.php?main_page=product_info&cPath=29_33_54&products_id=325&zenid=a456cb17f20a56fe3f70d3887960e3a5
The tool is available for about $40US, you can disassemble it yourself, then take it to a shop for thread repair .
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Thanks Bob. Will bookmark this for when we decide to pull things apart. For now will try plugging it and making due as the riding season is short up here and all too soon it will be going into the hangar (aka motorcycle storage unit) for the winter.