Posts
90
Joined
3/11/2017
Location
Opp, AL
US
So I thought I was finally going to take my freshly built 06 RM 250 to the track but ran into a problem. The front brakes seem to be sticking and the rotor gets really hot just putting around the yard. The brake setup is a CRF master cylinder with Galfer steel line and 270mm rotor. The caliper bracket is sliding free on the pins. I am assuming I need a rebuild kit for the caliper. I took the caliper off and the brake pad out and pulled the brake lever. One piston comes out much farther/faster than the other so I took the caliper apart but the only thing I found was a little dirt in one of the seals(on the sticking piston). So I clean it up and put it back together but still not any better. Any ideas other than replacing the pistons and seals? Thanks!
Not sure how “over the top” my process is, but its the easiest way for me to solve brake problems. I dont like trying to chase down issues in the caliper or master cylinder. Re-do it all and be done. Its not expensive by any means.
Paw Paw
The Shop
I got hit by a stone off the rider in front of me which left my index finger throbbing and at the same time I lost the front brake with the lever travelling all the way back to the bars.
It definitely reacted like a bent disc, although I have experienced a damaged seal in the master cylinder after a collision previously, and considering it was linked to the hit to hand this was my first assumption. Anyway, on inspection at the track the disc did have a bend to it, so I ordered a new disc and seal kit for the master cylinder just to cover both bases.
I fit both parts last night and this whole thing has me scratching my head, bled the system through but couldn't get a good feel at the lever. When operating it's as if the caliper isn't sat straight as you can see the disc flexing from the bottom.
If I remove the wheel I can get a great feel at the lever, which suggests to me that the problem is either with the new disc or the caliper mounting.
I can improve things by shimming the caliper at the top mounting bolt, but I shouldn't need to do that and the feel at the lever is still not as good as should be.
It seems to me that the problem is somehow with the mounting of caliper and it is running at a slight angle. Quite how this can happen by being smashed with a stone at the master cylinder end I don't know. I'm not a big believer in coincidence.
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