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Author Topic: Front brakes went from firm to squishy to firm  (Read 966 times)

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Offline kenickie

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Front brakes went from firm to squishy to firm
« on: June 10, 2009, 05:35:47 PM »
I rebuilt my front brakes several months ago, which entailed tearing apart the caliper, cleaning the caliper groove, polishing the piston, bleeding the old fluid and replacing with new fluid, and bleeding until I had a firm lever. No problems for months, then two days ago they turned to mush, and now today they're back to being firm as before. Is this indicative of an air pocket, or something more serious? (I don't have an OEM MC, the PO mounted the MC you see in the attached picture.)
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Offline Hush

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Re: Front brakes went from firm to squishy to firm
« Reply #1 on: June 10, 2009, 06:18:18 PM »
An airpocket would stay in the system until it was bled off, unless you were really really go get a lottery ticket lucky and the air bubble travelled up to the MC and cleared itself!
Mind you that is probably the only explanation if your scenario is correct....go buy a lottery ticket. :D
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Offline Caaveman82

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Re: Front brakes went from firm to squishy to firm
« Reply #2 on: June 10, 2009, 06:30:04 PM »
How are your lines looking?
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Offline kenickie

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Re: Front brakes went from firm to squishy to firm
« Reply #3 on: June 10, 2009, 10:14:43 PM »
Hush - I'll be buyin' that ticket tomorrow for sure - good suggestion.

Caave - Lines are good. I gave 'em the once-over to see if there were bulges, kinks, breaks or leaks. Saw nuthin.

Took a fast ride home tonight and the brakes stop me good. hmmmm....
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Offline mystic_1

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Re: Front brakes went from firm to squishy to firm
« Reply #4 on: June 11, 2009, 05:23:03 AM »
That's a concerning problem, imagine your brakes going soft again on you when you need them for a panic stop.

Do you know where that master cylinder comes from?  I'd strongly consider getting a rebuild kit for it, if the cups are going bad they could be allowing some air into the system up there.

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Offline Frankencake

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Re: Front brakes went from firm to squishy to firm
« Reply #5 on: June 11, 2009, 05:46:20 AM »
Have there been any drastic changes in the weather in you neck of the woods?  Heat changes will make for expansion and contraction of fluid.  My other bike has a mysterious brake system.  Sometimes the lever has less travel than other times.
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