Walking Eagle
New member
Seeping Master Cylinder Res Diaphragm/Gasket
Greetings,
The above says it --
Funny thing - even though I "think" this is probably a diaphragm/gasket with a 1993 birthday ('94 R1100RS), it looks absolutely new, is completely pliable, and shows NO signs of deterioration, no minute cracks, etc.
After I drained the system for new SS line install, I buttoned everything back up, and went for a ride yesterday. After about 30 fun-filled miles, I happened to look at the master cylinder, and there was considerable seepage from the rearmost edge of the seam - enough to sling a few drops of this deadly fluid onto the $$$ upper "ledge" of the tank! Once I got my heart pumping again, I quickly stopped, wiped everything clean and did a quick rinse beside the road - no damage to paint, but this could have been a disaster.
After wiping everything down and a quick rinse beside the road, I headed home, and figured that I had overfilled the M Cyl reservoir. The screws were pretty tight, although I was careful to not overtighten and squish the diaphragm/gasket, and used a cross-pattern.
When you turn the bars of the RS to full-lock on the left, the top of the M Cyl sits pretty level, which is the position I used to do the fill/bleed to prevent spills (full plastic drape, of course). This is the position it was in when I filled it to within about 3/8" from the top, and thus think I overfilled. Then, when flying straight-and-level the M Cyl tilts pretty sharply downhill, so that the fluid rests right against the back and right edge of the seams between the top and body of the reservoir.
I sucked out about 1/3 of the fluid, which still left plenty, with the aim being to get the "resting" level BELOW the rearmost seam. I left the bike sitting overnight on the centerstand, wheel pointed straight ahead, so the M Cyl tilts in the "normal" riding position. I just looked at it, and DAMN -- a line of fluid seepage still shows. I'm not absolutely positive that the level is below the seam, but am not willing to pull any more out of the reservoir and this isn't a "permanent fix" anyway -- this clearly shouldn't be leaking, even when fluid rests against the seam - at least that's my opinion.
NOTE: The threaded bolt holes did NOT have any residual fluid in them, so this isn't the issue.
Obviously I'm ordering a new diaphragm/gasket this morning, but this one is a puzzler to me.
QUESTION (finally) -- do these things somehow get "fluid-logged" (?) and quit sealing? I've opened and closed a lot of M Cylinders in my time, and this problem is new to me (as is the machine - under a year).
Thanks, and sorry that this turned into such a long post.
UPDATE: I'm watching this thing like a hawk, and it keeps seeping at the top seam, so I think the fluid must still be "up there." NEW INFO is that I need a M. Cyl rebuild kit, too. I'd thought that the seepage from the top seam put the deadly drops onto the tank, but NO -- fluid oozing out of the lever housing. Oops - I know what that means! More dough to the great guys at BBY! Open on Mondays!
Walking Eagle
Greetings,
The above says it --
Funny thing - even though I "think" this is probably a diaphragm/gasket with a 1993 birthday ('94 R1100RS), it looks absolutely new, is completely pliable, and shows NO signs of deterioration, no minute cracks, etc.
After I drained the system for new SS line install, I buttoned everything back up, and went for a ride yesterday. After about 30 fun-filled miles, I happened to look at the master cylinder, and there was considerable seepage from the rearmost edge of the seam - enough to sling a few drops of this deadly fluid onto the $$$ upper "ledge" of the tank! Once I got my heart pumping again, I quickly stopped, wiped everything clean and did a quick rinse beside the road - no damage to paint, but this could have been a disaster.
After wiping everything down and a quick rinse beside the road, I headed home, and figured that I had overfilled the M Cyl reservoir. The screws were pretty tight, although I was careful to not overtighten and squish the diaphragm/gasket, and used a cross-pattern.
When you turn the bars of the RS to full-lock on the left, the top of the M Cyl sits pretty level, which is the position I used to do the fill/bleed to prevent spills (full plastic drape, of course). This is the position it was in when I filled it to within about 3/8" from the top, and thus think I overfilled. Then, when flying straight-and-level the M Cyl tilts pretty sharply downhill, so that the fluid rests right against the back and right edge of the seams between the top and body of the reservoir.
I sucked out about 1/3 of the fluid, which still left plenty, with the aim being to get the "resting" level BELOW the rearmost seam. I left the bike sitting overnight on the centerstand, wheel pointed straight ahead, so the M Cyl tilts in the "normal" riding position. I just looked at it, and DAMN -- a line of fluid seepage still shows. I'm not absolutely positive that the level is below the seam, but am not willing to pull any more out of the reservoir and this isn't a "permanent fix" anyway -- this clearly shouldn't be leaking, even when fluid rests against the seam - at least that's my opinion.
NOTE: The threaded bolt holes did NOT have any residual fluid in them, so this isn't the issue.
Obviously I'm ordering a new diaphragm/gasket this morning, but this one is a puzzler to me.
QUESTION (finally) -- do these things somehow get "fluid-logged" (?) and quit sealing? I've opened and closed a lot of M Cylinders in my time, and this problem is new to me (as is the machine - under a year).
Thanks, and sorry that this turned into such a long post.
UPDATE: I'm watching this thing like a hawk, and it keeps seeping at the top seam, so I think the fluid must still be "up there." NEW INFO is that I need a M. Cyl rebuild kit, too. I'd thought that the seepage from the top seam put the deadly drops onto the tank, but NO -- fluid oozing out of the lever housing. Oops - I know what that means! More dough to the great guys at BBY! Open on Mondays!
Walking Eagle
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