yz85 front brake problem

I was riding the other day and had a bit of a stack. my bike landed on the front calliper pretty hard . there is pressure for about a second before it goes spongy, i took the master cylinder apart. it looked clean and the orings look like new?
 
I was riding the other day and had a bit of a stack. my bike landed on the front calliper pretty hard . there is pressure for about a second before it goes spongy, i took the master cylinder apart. it looked clean and the orings look like new?
Have you put it back together and bled it yet? You may have had air in the system, although it usually is the opposite symptom (spongy then firm) but it may have just needed bled, also make sure there is no looseness in front wheel bearing, or bent caliper mounts.
 
i am curious as to your caliper taking a hit and you worked on the master cylinder. I think you have gotten air into the system. bleeding those can be a real chore as I have yet to see the time honored method of pumping the brake handle work to my satisifaction.
 
Sounds like a bad caliper or brake piston... Inspect the caliper thou roughly for cracks or broken seals. Especially in the piston area.
 
As long as it's not leaking anywhere it's likely that the only issue is air in the line as described. It can be tough to bleed the front as you are trying to push the bubbles down. If you can detach the caliper and raise it above the master cylinder, it's a lot easier. Just be sure to put something between the pads or you will push the caliper piston out of the bore.
 
my first shot when crash related bleeding is necessary is the same one I use trailside: push the piston back into the caliper (prying at the brake pad works in most cases) and then pumping it up tight a time or two
 
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