lucky7s Posted April 3, 2008 Report Share Posted April 3, 2008 Took my txt out for a shakedown yesterday to see how it goes (only got it on monday) and after about 20 mins of riding the rear pads were smoking hot and the caliper was siezed solid. Managed to get it cooled off before the pads lit up..... by peeing on it bit low tech i know but it worked! Hooked the pads out to have a look at whats causing the binding issue, and found all four pistons to be moving freely so i took the lid off the fluid reservoir and tried to push the pistons back to get the pads back in, as you would with most braking systems. Problem is, all thats happening is that as you push one pot back, the other one on that side of the caliper pops out. Doesn't seem to be pushing the fluid back up the system. I'm stumped - is there a non return valve in the master cylinder or something? I've managed to get the pads back in by cracking off the bleed nipple and pushing the pistons back but i'm now gonna have to rebleed the system....not an ideal solution really. Any suggestions welcomed Quote Link to comment Share on other sites More sharing options...
bostit Posted April 3, 2008 Report Share Posted April 3, 2008 Check that the brake lever and the push rod into the master cylinder has not been adjusted so as to stop the flow of fluid back into the reservoir. The push rod needs to be loose ie. not pressing hard on the master cylinder. I had this problem and it cost me a new hose when it exploded and heart failure when it happened again in the SSDT (cooled by a bottle of water from the Army). Quote Link to comment Share on other sites More sharing options...
lucky7s Posted April 3, 2008 Author Report Share Posted April 3, 2008 Check that the brake lever and the push rod into the master cylinder has not been adjusted so as to stop the flow of fluid back into the reservoir. The push rod needs to be loose ie. not pressing hard on the master cylinder. I had this problem and it cost me a new hose when it exploded and heart failure when it happened again in the SSDT (cooled by a bottle of water from the Army). The guy i bought it from mentioned something about the rear brake but i was too busy drooling over my shiny new bike to pay much attention He fitted a braided rear line though, so i suspect its a problem he was having too, with possible hose failure consequences much like your own. Thanks very much for the tip - i'll be having a look in a bit......off work today and its good weather for riding so would be nice to take the bike out Quote Link to comment Share on other sites More sharing options...
yamahaty250xox Posted April 3, 2008 Report Share Posted April 3, 2008 unbolt the brake hose and let all the fluid out. clamp 1 piston with grips and push the other in. it will be hard but keep trying. bleed it up and go riding. dont ask me the science behind this but it worked for me. max Quote Link to comment Share on other sites More sharing options...
lucky7s Posted April 3, 2008 Author Report Share Posted April 3, 2008 (edited) Tried all of the above - thanks for the suggestions guys. 10 minutes riding though and it was on fire again. Traced problem to a slightly warped disc....Grrrrr! Got one ordered from BVM so its thumb twiddling time again *edit* or so i thought....just had the disc checked for flatness at a local engineering place and its apparently fine. Losing the will to live now Edited April 3, 2008 by lucky7s Quote Link to comment Share on other sites More sharing options...
jse Posted April 3, 2008 Report Share Posted April 3, 2008 Tried all of the above - thanks for the suggestions guys. 10 minutes riding though and it was on fire again. Traced problem to a slightly warped disc....Grrrrr! Got one ordered from BVM so its thumb twiddling time again *edit* or so i thought....just had the disc checked for flatness at a local engineering place and its apparently fine. Losing the will to live now My guess it that the warped disc is the secondary problem leading up to the overheating, which is the primary one. A warped disc would tend to push the pucks back so that when the lever is pressed, it would feel like there are no or weak brakes and the lever would have to be pressed a couple of times to take up the "slack". A rider may then think that by tightening up the pushrod (lengthening the pushrod) that goes into the M/C, that will fix it, which it does in a way, but it creates a much more serious problem by closing off the system (the M/C piston must retract back to the circlip stop in order to open the system) and causing drag, which heats and expands the fluid, causing more drag, more heat etc. and the condition you describe. Take off the rubber boot and double check that the piston comes down to the circlip and it takes a little pressure to push in (the return spring may be sacked) and you can feel slack before the pushrod starts to press into the M/C boot where it contacts the piston. 99% of the time, thats the cause of back brakes overheating. Jon Quote Link to comment Share on other sites More sharing options...
2kracing Posted April 3, 2008 Report Share Posted April 3, 2008 The same thing happened to my 300 Raga this weekend. The back brake would drag and get very hot. I fount that after taking the master clinder apart it had goo in it. after cleaning the M/C and lines out, everything is fine now. JK Quote Link to comment Share on other sites More sharing options...
jse Posted April 4, 2008 Report Share Posted April 4, 2008 The same thing happened to my 300 Raga this weekend. The back brake would drag and get very hot. I fount that after taking the master clinderapart it had goo in it. after cleaning the M/C and lines out, everything is fine now. JK That's weird, I usually only see that when riders mix DOT-3/4/5.1 with DOT-5 or the fluid is really old. Don't forget that the rear brake reservoir on the GasGas is not vented like the clutch/front brake ones (which should be a little overfilled when attaching the cap/bladder to prevent moisture getting in) and should only be filled about 2/3rd's of the way, so there's room for expansion. Jon Quote Link to comment Share on other sites More sharing options...
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