front brakes bleeding down quickly

[joetrailer]

Yesterday after not riding my bike for a couple months my front brakes were squishy.. I assumed it was air in the lines or at least something that a quick bleed would fix..

I popped the reservoir cover off, pulled out the existing fluid added some new and bled the mc and both calipers off then refilled the reservoir and put the cap on. At which time the lever was hard and each pull was good wait 5 seconds and the lever goes all the way to the bar squeeze a few times and it's good for a few seconds .

I've bled brakes before and have never had a problem so I assume I know what I'm doing I have no fluid leaks that I can see. I'm not seeing bubbles in a test bleed so I figure all my connections are air and fluid tight. I'm wondering if it could be the check valve in the mc? Is that something I can replace separate from the mc itself?

Any thoughts?

 

[card16969]

possibly leaky seal in the brake caliper itself and you just havnt seen the leak yet?

 

[Ludicrous Speed]

Or a bad master cylinder that is bleeding back into itself

 

[Tufbusa]

I agree with Ludicrous, if there is no fluid visible anywhere it's most likely the seals in the mastercylinder.

 

[SlowBoyMoto]

I agree with Ludicrous, if there is no fluid visible anywhere it's most likely the seals in the mastercylinder.

Has happened to me, sounds like what he is experiencing as well (as others said, as long as there is no visible leaks anywhere)

 

[dmallord]

if no fluid loss... master cylinder bypassing(internal leakage).

 

[GIXERHP]

Master cylinders can go bad just sitting! Also they are not to hard to rebuild!

 

[joetrailer]

Not sure yet. But, I ordered a cup and piston kit for $30 and the new brake lines I wanted we'll see. Thanks.

 

[sailboatjoe]

Id liketo see what you find Im suffering the same issue.