Leaking Clutch Slave?

[Tarkus]

I noticed recently that my clutch seemed like it was not disengaging as soon as it should when pulling in the clutch lever.  Conversely it would engage a little sooner when letting out.  It must have been a gradual subtle change because I thought it might have been my imagination at first.  Then one day it failed to fully disengage with the clutch lever completely depressed.  Opened up the MC and it was empty.  Refilled it and now it's back to normal...at least for now. My first thought was that the clutch slave may be leaking.  I inspected the clutch cover and haven't see any obvious signs of leaking from the slave.  I don't notice any other exterior signs of a leak anywhere else either.  But it seems only logical that if the fluid level in the MC recedes, the fluid must be escaping from somewhere.  Right? 

Kind of at a loss here.  Any suggestions on other possible leak sources would be greatly appreciated.  I'm currently in the process of rebuilding the brake calipers.  So if need be, this would be a good time to get the parts needed to resolve this issue too while I'm down for maintenance.
 
Thanks in advance

[indybobm]

Maybe they just need to be bleed. Good time to change the fluid in the process.

[ridingron]

Check the brass bushing in the lever. It has to be disassembled to be inspected. The push rod fits into a shallow hole (about .090") in the push rod. The hole will wear deeper losing stroke of the piston. The bushing should be available (used on numerous models) for about $10. I'm not sure, but I think the nut on the pivot screw is a jam nut. Loosen it then the screw.

[Ricky-D]

I think it may be possible for fluid to leak by way of the slave cylinder cup (22865-MJ8-003) into the engine. Seeing no obvious leaking from the master cylinder, or on the outside of the clutch cover I think the only answer is the cup.

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[98valk]

slave rebuild info
https://www.goldwingfacts.com/forums/2-goldwing-technical-forum/481498-99-gl1500-clutch-problem-help.html

[scarylarry]

I had to rebuild mine last year..sounds like the same symptoms

[Tarkus]

Thanks guys.  As Ricky-D pointed out, I suspected the cup would be the most likely part to fail.  In any case it seems like a total rebuild is in order. Thanks 98valk for the helpful link. But I'm still a little perplexed as to how the fluid would end up inside the crank case, as opposed to leaking to the outside.  I notice in the parts diagram there is an oil seal (91204-MB0-013), in addition to the oil seal for the piston.  I figure it's probably a good idea to replace that too while I'm at it.  But is it possible for fluid to leak past that seal into the engine...given that it's working properly?  I'm just assuming it's there to prevent any kind of cross contamination.  But then again, maybe not.

[MnM Valk 97]

Sure, it can leak past the inner diameter of the seal in the clutch cover, into the engine. Virtually no oil pressure on the other side of the seal. When you squeeze the clutch the fluid can seep past the clutch lifter rod, into the rear case.
My clutch cover was quite corroded when I opened it, as was a bonus clutch cover that showed up in an eBay grab-bag purchase. The lifter rod wasn't great, either. The seal was starting to distort from the force of the expanding corrosion products, too.
I cleaned up the lifter rod and swapped ends when I put it back. I plan to bleed it tomorrow; if something goes wrong I'll post the results.
I'm the third owner of the bike, but I'm not sure what the previous owners - or their shops - did for preventative maintenance. I'll be diligent about annual fluid flushes from now on. I plan on riding it to the moon!