poopipe Posted August 8, 2005 Report Share Posted August 8, 2005 I'm either completely missing the point or I'm a genius so someone who knows what they're talking about might be able to let me know either way. An open system hydraulic brake has a reservoir on it with space for a bit of air at the top - presumably to allow for fluid expansion etc. This means that if you turn your bike upside down and pull the lever you get air on your tubes and you have to bleed it.. am i right so far? assuming I am... why don't they just put a seal that floats on top of the fluid inside the reservoir, that way when you turned it upside down the air wouldn't rise to the top of the reservoir even if you did pull the lever. I don't have a disc so I could well be way off the mark on this but it seems pretty logical to me. any thoughts? Quote Link to comment Share on other sites More sharing options...
Connor Posted August 8, 2005 Report Share Posted August 8, 2005 Not true downhill bikes flip over all the time, in mid race, i dont see them bleeding there brakes every time there bikes flip over seconds. :huh: Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted August 8, 2005 Report Share Posted August 8, 2005 An open system hydraulic brake has a reservoir on it with space for a bit of air at the top - presumably to allow for fluid expansion etc. This means that if you turn your bike upside down and pull the lever you get air on your tubes and you have to bleed it.. am i right so far? ← The idea is, that you fill the reservoir right to the top, then push in the top cap/diaphragm, so theres no air room. When you pump the brake, the diaphragm is 'sucked' downwards. So, unfortunately not... nice idea though! Quote Link to comment Share on other sites More sharing options...
Tom Rigg Posted August 8, 2005 Report Share Posted August 8, 2005 The levers already have a seal at the top of the reservoir to do exactly what youve just mentioned :huh: Quote Link to comment Share on other sites More sharing options...
poopipe Posted August 8, 2005 Author Report Share Posted August 8, 2005 fair enough - can't get there first everytime :huh: Quote Link to comment Share on other sites More sharing options...
Mr Motivator Posted August 9, 2005 Report Share Posted August 9, 2005 Nirr, I play with my brake upside down all the time and its fine. (Y) Quote Link to comment Share on other sites More sharing options...
JT! Posted August 9, 2005 Report Share Posted August 9, 2005 Why do disc brakes have all that resevoir (sp?) stuff. Why can't it be nice and simple like a maggie? (Y) Quote Link to comment Share on other sites More sharing options...
dave85 Posted August 9, 2005 Report Share Posted August 9, 2005 Fluid expands when it gets hot, on a closed system it'll eventually lock the brakes up solid, not desirable when your bombing down a hillside. And the other way, it lets the system adjust for pad wear. Quote Link to comment Share on other sites More sharing options...
Lawnmowerman Posted August 9, 2005 Report Share Posted August 9, 2005 The fluid gets hot and expands Quote Link to comment Share on other sites More sharing options...
Swindon rider Posted August 9, 2005 Report Share Posted August 9, 2005 (edited) I will remove this as ive just said exactly what the 2 above posts say. but did not read them first. stu Edited August 9, 2005 by Swindon rider Quote Link to comment Share on other sites More sharing options...
Bill Posted August 10, 2005 Report Share Posted August 10, 2005 (edited) Not true downhill bikes flip over all the time, in mid race, i dont see them bleeding there brakes every time there bikes flip over seconds. (Y) ← if the brakes get pulled at the same time that it is upside down you do. also after the bike has bounce doff odwn the hil the bite points onthe brakes often change. The Hope o4 or one of the 4 pot brakes ahd a floating seal/diaphram thing in the lever 'cos i had one, and when it was low on fluid th ebite would gradually get closer to the bar but i could fix it by taking the cap off the res and pushing the floating seal bit down. may as well use a closed system for trials though as the flud is never gnna get very hot. Edited August 10, 2005 by Bill Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.