billyt Posted December 22, 2011 Report Share Posted December 22, 2011 (edited) "I usually perform 2-3 good hard stops from a good high speed run in 5th gear to warm them, then let them cool and resume normal operation. Do this 2-3 times to thermocycle them, then on a final trip do the same to get them and the disk good and hot and douse them with a water bottle to steam off." Warning to the wise on getting your disk hot and then dosing it in cold water! I have witnessed this resulting in the disk cracking and or warping due to the aneling effect that the radical drop in temperature causes. I was present when a friend of mine tried this and and then went over the bars after the brake disk shattered Edited December 22, 2011 by BillyT Quote Link to comment Share on other sites More sharing options...
copemech Posted December 23, 2011 Report Share Posted December 23, 2011 "I usually perform 2-3 good hard stops from a good high speed run in 5th gear to warm them, then let them cool and resume normal operation. Do this 2-3 times to thermocycle them, then on a final trip do the same to get them and the disk good and hot and douse them with a water bottle to steam off." Warning to the wise on getting your disk hot and then dosing it in cold water! I have witnessed this resulting in the disk cracking and or warping due to the aneling effect that the radical drop in temperature causes. I was present when a friend of mine tried this and and then went over the bars after the brake disk shattered That is of interist, Billy! I suppose it is possible, and as stated, I think one needs to be a bit cautious about this process as not to overdoo things as excess heat here is not a good thing. In my mind, you kinda have to relate this to what may be encountered in normal usage, say for example a good ride on the loop, then hitting water crossings and streams. The brakes doo heat up quickly, as they are not the size of an enduro bike. Quote Link to comment Share on other sites More sharing options...
billyt Posted December 23, 2011 Report Share Posted December 23, 2011 Mark Yes it is all relative and one has to use some common sense when doing this heat/cool technique. Saying "get it hot" is all relative to whom ever is doing the "getting it hot". The guy I saw doing this got it so hot it was almost changing colour no wonder the cool water he poured over it (the water came out of his ice ladened cooler) caused a rapid drop and subsequent hairline cracking of the disk and then when he rode placing stress on the disk going down a BIG hill BINGO! over the bars he went as the brake pads caught on the crack. Not good............... Quote Link to comment Share on other sites More sharing options...
toothandnail Posted December 23, 2011 Report Share Posted December 23, 2011 We had a 2000 sherco in our group that had the same troubles , it made the rounds through 4 guys in the group , each one thought they could fix it , none did , , the ONLY thing that wasn't changed/new was the line , I told them all ,I thought that was the problem all along,it looked to be some kind of plastic. Other than the brakes that bike was in PERFECT cond. Here's what I remember being replaced. 1st owner, bled brakes, pads,rebuilt caliper 2nd bled brakes , new disc, honda master cyl. that helped the most 3rd bled, pads, new caliper 4th bled ,new sherco master cyl. all that and NOBODY replaced the line Quote Link to comment Share on other sites More sharing options...
charliechitlins Posted December 23, 2011 Report Share Posted December 23, 2011 Brakes that won't stop being spongey often have a bad line. It can be weak internally and you can't see the problem. You could try bleeding the master itself. Take the line off, put you r finger over the hole and pump. Keep the lever pulled in and re-attach the line. This is often a problem with larger volume masters on street bikes and such, but you might as well try it. That being said...the only bike that drove me completely insane with spongey brakes had me replacing every component. Unfortunately, the line was replaced last and it turned out to be the problem. Quote Link to comment Share on other sites More sharing options...
comerconstructionman Posted December 23, 2011 Author Report Share Posted December 23, 2011 Brakes that won't stop being spongey often have a bad line. It can be weak internally and you can't see the problem. You could try bleeding the master itself. Take the line off, put you r finger over the hole and pump. Keep the lever pulled in and re-attach the line. This is often a problem with larger volume masters on street bikes and such, but you might as well try it. That being said...the only bike that drove me completely insane with spongey brakes had me replacing every component. Unfortunately, the line was replaced last and it turned out to be the problem. Ill have a look at the lines... Im pretty sure its not the disks. Quote Link to comment Share on other sites More sharing options...
b40rt Posted December 23, 2011 Report Share Posted December 23, 2011 Just a thought - how do my cars brakes work so well when I didnt go all the "conditioning " ? Quote Link to comment Share on other sites More sharing options...
copemech Posted December 24, 2011 Report Share Posted December 24, 2011 Just a thought - how do my cars brakes work so well when I didnt go all the "conditioning " ? That is a good question, yet fact is most are not 100% off new. Yes, they will work fine in normal stops, yet in a panic stop they are not there yet, maybe at only 70-80% capacity and may not skid the tires on dry pavement. As most modern cars have ABS systems now, the job of the brakes is not to skid the tires, but to bring them to the initial skid point, and then the ABS takes over allowing maximum braking while backing off enough to maintain steering and directional control so you cannae lock a wheel anyway! We recently installed a set of Brembo disks and calipers on a customer car. The break in procedure was soo intense and with cautions ov overheat that we felt it best left to the owner to perform. It was rediculous! Front brake on the bikes is the one that does the normal work in the sections. And folk like them quite sharp in most cases. Must lock wheel NOW! And doing it with one finger! Quote Link to comment Share on other sites More sharing options...
comerconstructionman Posted December 27, 2011 Author Report Share Posted December 27, 2011 The wavy disks on some earlier modes tend to squeal badly. Non of this has anything to do with stopping ability. Seems to me if you have decent initial pressure build in the levers things have little to do with the master cyl's, although I suppose one could have some sticky pistons in the calipers, yet still seems unlikely in the newer bike. Have you done the thermo cycling and proper dousing with water yet? Many times this works wonders! Mind you the dousing could require a few tries, then let them dry. Ill have a go tomorrow copemech and let you know... Quote Link to comment Share on other sites More sharing options...
comerconstructionman Posted December 28, 2011 Author Report Share Posted December 28, 2011 (edited) Thanks for all your input on this thread people brakes are excellent now. Did some fast riding and lots of breaking and just think they needed bedding in. Went practising today and they were fantastic. Would say one thing though that the rear brake is really sharp which is good but the rear wheel doesn't spin that freely when in neutral. Not sure if the pads are grinding a bit on the disk. Rear wheel does spin freely but not maybe as it should. Nick Edited December 28, 2011 by comerconstructionman Quote Link to comment Share on other sites More sharing options...
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