eviljim Posted July 12, 2014 Report Share Posted July 12, 2014 (edited) I have a beta rev 3 2002. It's my first trial bike, I have had it about a month. It was a little un loved, so needs a bit of tinkering, which it is getting. I am working thought it Anyway, I actually rode it last week, and the rear brake started to bind, so after looking at it I decided to rebuild the calliper new seals and pistons. Putting it all back on and it's not working as it should. I have looked around the internet, I did before I did the work. I am now stuck for what to do next. Symptoms are. Very little brake pressure Most of the time a spongy feel. Ie does not brake very much I have done the following Rebuilt callipers. 4 pot ajp's Pushed the pots fully in when building. ( I did not pre fill the calliper with fluid, could this be my error) Bled in the normal way, I did not use the leaver but rather a device to push the piston Up the MC to get more movement. this did not work so I have now used a syringe to back feed the system. I have also used a syringe to presure the system form the top (removing reservoir) I have done this with the MC and reservoir removed a placed it a better position it at the top with no loops int the cables. I have also removed hole system and then advanced the pots further than they could on the bike then pushed back to get back on the bike. It feels like there is air in the system but i can't think were it is. oh I have also undone the banjo on the MC in an attempt to bleed that too. I am not sure I did the very well, one person pressure the MC I undid the banjo fluid came out did it back up again, did this twice. So after spending too much of my very limited time on it I am at the end of my tether. Help, All I can think of is the get the pots out and fill the calliper with fluid before putting them it but I don't think this is the issues. Or maybe bleeding the MC better This may not make a lot of sense As I am doing it on my iPad, I am dyslexic, I am tired and my wife is talking to me. I will re read and correct tomorrow, Edited July 13, 2014 by eviljim Quote Link to comment Share on other sites More sharing options...
shercoben12 Posted July 12, 2014 Report Share Posted July 12, 2014 as for not much pressure? just an idea but maybe you have a tiny pin prick hole in your hose? a friend on a gasgas 2013 racing had the problem of not much pressure and spongy feel and little power. all turned out to be the tiniest of hole in the hose. i mean tiny... hose replaced , job done. i hope you get to the bottom of the problem! good luck Quote Link to comment Share on other sites More sharing options...
0007 Posted July 13, 2014 Report Share Posted July 13, 2014 Remove hose from master, bleed master Attach hose, bleed hose disconnected from caliper, pinch the end between fingers and bleed Connect hose to caliper, bleed until you want to kill yourself or until you have pressure whichever comes first, burping it at the banjos during the process Quote Link to comment Share on other sites More sharing options...
eviljim Posted July 13, 2014 Author Report Share Posted July 13, 2014 Thanks, don't think its a hole. It was working really will before it started to bind. I will put try bleading the MC on the bench. Quote Link to comment Share on other sites More sharing options...
scraggydog64 Posted July 13, 2014 Report Share Posted July 13, 2014 I had the same issue with my 4RT. Spent hours on it and did everything you did. I don't seem to have problems with road bike brakes but i do with trials bikes, especially rear brakes. Anyway after trying everything quite a few times I was told to get a Gunson Eezibleed. Its designed to bleed car brakes. It effectively puts fluid into the system with a small amount of air pressure. You use a tyre to provide the air pressure. You have to drill the reservoir cap to fit a nipple to attach it. Afterwards just remove the nipple and fit a plastic nut and bolt or get another cap. It got the job done in about 15 minutes. Quote Link to comment Share on other sites More sharing options...
popty bing Posted July 13, 2014 Report Share Posted July 13, 2014 I had exactly the same issue after I rebuilt my Rev-3 rear caliper. Tried and tried to bleed it, syringe, back bleed, etc..... to still have a totally pants brake!!! In the end I stripped the caliper completely to pieces and pushed all the pistons out and removed the seals. Next, I got a clean tub, filled it with brake fluid and re-assembled the caliper in the brake fluid to make sure that there was no air in the caliper. This was then connected to the rest of the brake system, re-bled and hey presto!, a working rear brake. One other thing to look at - when you put the pistons back in, make sure that the square section seals do not 'pick up'. This will cause you issues! Quote Link to comment Share on other sites More sharing options...
eviljim Posted July 13, 2014 Author Report Share Posted July 13, 2014 (edited) I keep my bikes at my mums place about 4 miles away for a few reason one of witch is she has a small paddock I can play in. So this means tinker time is tight I cant just nip out to the shed for a hour. Over the last week I must have spent 9 hours on this brake really eating into my bike time. Anyway spent another few hours tonight ended up with it on the bench to get the calliper nice and high, bled the MC, still crap, decide to double the size of the virtual disk in case the issues was crap pads and then loads of air started coming out, and kept end on coming so much I wonder if it's pulling air in. Or it could be there is a load at the back of the pistons. So, the next thing is the rebuild the calliper again. When I did it the first time I could not see or feel any difference In the seals, could I have put them in upside down? I did not pre fill with any fluid so I will do this this time. I now hate brake fluid. Edited July 13, 2014 by eviljim Quote Link to comment Share on other sites More sharing options...
eviljim Posted July 16, 2014 Author Report Share Posted July 16, 2014 So another 3 hours again tonight but I now have a working brake! I don't know why I am pretty sure there was some luck involved. I do not want to go though that again. No pleasure, only pain Quote Link to comment Share on other sites More sharing options...
mags Posted July 16, 2014 Report Share Posted July 16, 2014 (edited) Dont despair too much Jim! I've spent 2-3 hrs fabricating something... welding, grinding, machining only to realise as I'm painting it... needs a big mod or a total re-think... in the "bin of mark 1's" it goes"! I look at like this these days.... I'm working on my motorcycles! The immense pleasure far outweighs the pain! (Dot4Wink) Mags Edited July 16, 2014 by mags Quote Link to comment Share on other sites More sharing options...
eviljim Posted July 17, 2014 Author Report Share Posted July 17, 2014 (edited) Yes your correct, in general I get real pleasure working on motorbikes. I even enjoyed taking the brakes to bits and all that jazz, but i I did like bleeding the seeming random none sensical nature of the them and being covered in brake fluid. Next job swing are bearings, that should be more satisfying. Edited July 31, 2014 by eviljim Quote Link to comment Share on other sites More sharing options...
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