1993 K1100RS master cylinder

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dwerbil
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1993 K1100RS master cylinder

Post by dwerbil » Mon Feb 08, 2016 10:40 pm

Just finished putting in a couple new front M/C piston seals and was bleeding the brakes when I noticed brake fluid was
spraying up a bit inside the fluid reservoir. I emptied same to see a small pinhole that would squirt fluid when the lever was depressed. Pinhole is inside the circular dimple....

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I don't think this is normal behavior since a hydraulic system is closed. Can I epoxy this closed or JB Weld it, or am I screwed to replace this M/C?
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04 R1150RT ~ 78 R100/7 ~ 84 RS ~ 93 K1100RS ~ 65 R60/2
Randy in Round Rock

robert
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Re: 1993 K1100RS master cylinder

Post by robert » Tue Feb 09, 2016 12:19 am

It's normal and it needs to be there. Look at it -- it was machined there for a reason.

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George Ryals
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Re: 1993 K1100RS master cylinder

Post by George Ryals » Tue Feb 09, 2016 12:19 pm

That hole lets fluid back into the reservoir when the lever is released. Since the piston seal comes back to clear the hole when the lever is released, the initial movement of the piston going forward momentarily squirts fluid before the hole is covered by the seal.
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dwerbil
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Re: 1993 K1100RS master cylinder

Post by dwerbil » Tue Feb 09, 2016 3:01 pm

Well, I'll be. Ya' learn something every day.
Thanks for the info.
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04 R1150RT ~ 78 R100/7 ~ 84 RS ~ 93 K1100RS ~ 65 R60/2
Randy in Round Rock

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