315r Posted July 17, 2011 Report Share Posted July 17, 2011 (edited) Hello. For first time in my Hs33 and after 2 years of water bleed i feel lazy pistons, I think that the problem is in the master cilinder.. The thing is that this situation only happen under hot conditions. Today I have been training under criminal sun and the piston, master cilinder maybe, began to stick. I had touch the body pump and was really hot under the sun, when I put the bike under a shade of a tree the piston starts to work normal.. then I have tried to train something more and when I put the bike on the sun the cilinder become lazy again. This may be due the water bleed after 2 years plus the extra expansion of the material due the high temperature? How can I return to the normal situation? maybe bleeding again with oil? I realy prefer the feeling and response of water but... Somebody have been experimented this situation? Thanks! Edited July 17, 2011 by 315r Quote Link to comment Share on other sites More sharing options...
N.Wood Posted July 18, 2011 Report Share Posted July 18, 2011 Ha, I just posted a topic on this. Interesting to see you're also having problems. was it a particularly hot day? If its the first time its happened and you live in Spain I guess it must have been pretty damn hot? Quote Link to comment Share on other sites More sharing options...
315r Posted July 18, 2011 Author Report Share Posted July 18, 2011 (edited) Ha, I just posted a topic on this. Interesting to see you're also having problems. was it a particularly hot day? If its the first time its happened and you live in Spain I guess it must have been pretty damn hot? Hello! No, not specially hot (+/- 31º Celsius, maybe more under direct sun). I had ride in worse conditions of hotness with water bleed, this year and last year, for sure.. I was a defender of water bleed but now I'm quite confident that this situation is generated by 2 years of exposition of pistons to water aggravated by the hot day... sadly I'm quite sure to return to oil again What do you think? Do you have the same problem? Edited July 18, 2011 by 315r Quote Link to comment Share on other sites More sharing options...
N.Wood Posted July 18, 2011 Report Share Posted July 18, 2011 Well I asked because my mate who rode in the Cayman Islands (in the Caribbean, between Jamaica and Cuba) said his brake went shie and locked up in the heat, but 5 minutes under the air con and it was fine again. He tried numerous bleeds etc. but ended up having a brake sent from the UK with oil in it, which worked fine. Seems a similar problem! Quote Link to comment Share on other sites More sharing options...
315r Posted July 18, 2011 Author Report Share Posted July 18, 2011 Well I asked because my mate who rode in the Cayman Islands (in the Caribbean, between Jamaica and Cuba) said his brake went shie and locked up in the heat, but 5 minutes under the air con and it was fine again. He tried numerous bleeds etc. but ended up having a brake sent from the UK with oil in it, which worked fine. Seems a similar problem! Yeah! I know cayman islands, fantastic place! Mine locked up when I pull the lever, then I release the lever and the piston remain on the body pump like when the spring don't have enough power to return the piston to their place... I have here some shimano mineral brake oil that I listen that works better than magura's although, for sure, works worse than water.. Quote Link to comment Share on other sites More sharing options...
N.Wood Posted July 18, 2011 Report Share Posted July 18, 2011 Sounds like the same sort of thing. I spoke to Tarty about it and he recons it may be something to do with expansion causing the sticky pistons. One way to tell I guess would be to have the brake cold, ride in the heat till it locked up, cool the brake in water then see what happens. I will be going out to Cayman along with matey and a spare brake so I'm sure we can conduct some sort of test if we're not too busy drinking rum. Quote Link to comment Share on other sites More sharing options...
315r Posted July 18, 2011 Author Report Share Posted July 18, 2011 Sounds like the same sort of thing. I spoke to Tarty about it and he recons it may be something to do with expansion causing the sticky pistons. One way to tell I guess would be to have the brake cold, ride in the heat till it locked up, cool the brake in water then see what happens. I will be going out to Cayman along with matey and a spare brake so I'm sure we can conduct some sort of test if we're not too busy drinking rum. HAHA! Yeah, I listen something like the pistons with long time of water bleed absorbs water and they expand a little bit, for sure, under hot conditions they expand a little bit more causing the problem of, first of all, sticky pistons under hot conditions and finally sticky pistons under all conditions.... Be careful with rum mate.. Quote Link to comment Share on other sites More sharing options...
toastie Posted July 18, 2011 Report Share Posted July 18, 2011 put it on a diet, take the piston out of the body remove the seals and sand it down a tiny amount with some fine sand paper, then put it all back together and if it dont work take some more material off til it does. Quote Link to comment Share on other sites More sharing options...
Greetings Posted July 18, 2011 Report Share Posted July 18, 2011 I had this problem also. Pretty common. Quote Link to comment Share on other sites More sharing options...
315r Posted July 19, 2011 Author Report Share Posted July 19, 2011 (edited) put it on a diet, take the piston out of the body remove the seals and sand it down a tiny amount with some fine sand paper, then put it all back together and if it dont work take some more material off til it does. Interesting point, I listen this solution before, although I never find how to remove the piston out of the body and try to do it without any idea scares me :$ for sure, it have been explained before, but I can't find it. You can explain me some highlights to take out the piston? thanks in advance Edited July 19, 2011 by 315r Quote Link to comment Share on other sites More sharing options...
BradJohnson Posted July 19, 2011 Report Share Posted July 19, 2011 Interesting point, I listen this solution before, although I never find how to remove the piston out of the body and try to do it without any idea scares me :$ for sure, it have been explained before, but I can't find it. You can explain me some highlights to take out the piston? thanks in advance Taking the piston out is fairly easy, just push the pin out of the lever with a small allen key, take the lever out and with the 2011 maggys you have to loosen the hose so you can see 3 threads (the manual told me) and the piston should pop out, if not push the piston in and the spring should pop it out, hope this helps. Quote Link to comment Share on other sites More sharing options...
forteh Posted July 19, 2011 Report Share Posted July 19, 2011 If the master cylinder piston has swollen after being exposed to water then so will the slave pistons, unfortunately theres nothing you can do with them Quote Link to comment Share on other sites More sharing options...
315r Posted July 19, 2011 Author Report Share Posted July 19, 2011 (edited) Hello all! Thanks for the advices and comments. At the end I have bleeded my HS33 with shimano mineral oil (pink). And obviously it don't have the response of water but not too bad, could be better than magura royal blood. Today I have been riding, not under extreme hot, and it seems that works well.. Probably I kept this oil for a while, maybe I'm still in time to avoid damaging pistons.. Edited July 19, 2011 by 315r Quote Link to comment Share on other sites More sharing options...
N.Wood Posted September 22, 2011 Report Share Posted September 22, 2011 Well as a little update - I'm back from the Cayman Islands. We managed to do a bit of riding in between having the most fun i've ever had and both my brake and mateys brake were completely fine. Thats in about 30 degree heat and 90+ humidity. So who knows... Quote Link to comment Share on other sites More sharing options...
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