scorpa250 Posted January 2, 2009 Author Report Share Posted January 2, 2009 hello all,went out in the garage to check the brake and its gone again !!!!!!!!!! if you pump the pedal 5/6 times it returns ????? should i get my son to just ride it and see what happens ? Scorpa250 Quote Link to comment Share on other sites More sharing options...
mikee Posted January 2, 2009 Report Share Posted January 2, 2009 should i get my son to just ride it and see what happens ? Scorpa250 NO get the brake working 100% and then let your son ride the bike...... Quote Link to comment Share on other sites More sharing options...
stork955 Posted January 2, 2009 Report Share Posted January 2, 2009 Hmmm, I dont think you have a bleeding issue there. If it pumps back up it sounds almost like something is retracting the caliper pistons/pads back from the disc (Much like what you get when you fit new pads and have to pump the brakes back to the disc). Weird - maybe its worth leaving the reservoir cap off overnight and see if that makes any difference. Cheers, Stork. Quote Link to comment Share on other sites More sharing options...
scorpa250 Posted January 10, 2009 Author Report Share Posted January 10, 2009 Finally its 100% !!!! Fitted a new master cylinder and got a vacuum bleeder for cars, 2mins later its perfect. it must have been a combination of air and master cylinder ,the bleeder is so simple to use and sucks all the fluid and air out so quick but you need two of you 1 pouring fluid in and the other holding the pipe on the nipple . Scorpa250. Quote Link to comment Share on other sites More sharing options...
stork955 Posted January 10, 2009 Report Share Posted January 10, 2009 Excellent news! Glad you got it there in the end. Stork Quote Link to comment Share on other sites More sharing options...
ledref1 Posted April 16, 2009 Report Share Posted April 16, 2009 Just a response to enhearten those Beta brake bleeders, it is possible to bleed the rear brake in the conventional fashion. Well, perhaps slightly modified conventional fashion. All it takes is a special tool - patience! Remove the rear wheel so you have room to woork, keep the reservoir uncapped and topped up, pump the brake pedal gently, and before opening the bleed valve, slowly move the caliper (up, down, sideways, etc.). After doing this a few tmimes, I have found that letting things sit for 15 minutes is also very helpful. In words, take full advantage of that patience tool. All other things being okay, the air will bleed and brakes will appear. Good Luck! Quote Link to comment Share on other sites More sharing options...
grahamjayzee Posted July 10, 2009 Report Share Posted July 10, 2009 I thought I'd stick an update on my Beta rear brake woes for anyone that is presently retrieving all the spanners they have hurled around the garage in frustration whilst trying to achieve decent braking! I stripped and cleaned my 4-pot Rev3 rear brake caliper and replaced the pistons and seals. This was due to the rear brake binding. I had taken all the usual precaustions (ensuring sufficient play in the operating rod, keeping them clean etc) but knew that I had to do a strip and service at some point. This led to the usual frustrations trying to get the system to work again. I subsequently replaced all the master cylinder seals but still could not get the pedal to firm up. Here's one thing I discovered; despite GREAT care assembling the brakes, it is extremely easy to nip the seal when pushing the pistons home. I did this by hand and don't have a vice-like grip. I didn't feel any untoward resistance but still nipped 2 of the seals. After days of trying to get pressure, dissassembly revealed damage to 2 seals and as a result, pressure could escape. I'm pretty hopeful I've found the problem now, but if you are having issues, here's my recommended advice: If you service, replace the master cylinder seals as well. It's only a little more than an ayrton and saves loads of doubt.Take the caliper off and tie it to the rafters or somesuch so it is as high as you can get it. the air rises pretty well if you do this.Take extreme care sliding the pistons home. Use plenty of clean brake fluid and really take your time.Keep plenty of free-play in the push rod. If you don't the transfer port remains covered and you won't get a full charge of fresh fluid when you bleed. Keep with it people, unnecessarily tricky, but you'll get there in the end. Graham Quote Link to comment Share on other sites More sharing options...
wanariot Posted July 10, 2009 Report Share Posted July 10, 2009 Good, the story goes on..........and have beta come up with a mod kit yet,,,,, errr no. But I did eventually sort mine, and it was nothing to do with lack of patience....(ledref1) . or my methods. I had replaced the master cylinder and after about 60 hours in the garage trying to get it to bleed i realised Lampkins had sent me the wrong one. Anyone struggling with their rev 3 rear brake needs to make sure you have the CORRECT master cylinder as they look identical on the outside but the internals are different. PLEASE NOTE; THE 4 POT REAR BRAKE UP TO AND INCLUDING YEAR 2004 HAS A MASTER CYLINDER WITH AN INTERNAL DIAMETER OF ABOUT 10MM. AFTER 2004 WHEN A 2 POT REAR CALIPER WAS USED, THE INTERNAL DIAMETER OF THE MASTER CYLINDER WAS ONLY ABOUT 6MM. WHICH MAKES SENSE. THE LATER WILL NOT WORK ON THE FORMER !!!!!!!!!!!!!!! TIP; Use the correct hydraulic compatable grease (coloured red) to assist in fitting your pistons/seals in your caliper. Its better than brake fluid, things slide in easier, think KY gel ! ! Quote Link to comment Share on other sites More sharing options...
grahamjayzee Posted July 10, 2009 Report Share Posted July 10, 2009 Yep, concur. The actual dimensions are 13mm for 4 pot and 9.5mm for 2 pot. BTW, I mis-ordered the 2 pot type. It's sat on me desk here. Anyone send me a tenner, it's theirs... Graham Quote Link to comment Share on other sites More sharing options...
grahamjayzee Posted July 10, 2009 Report Share Posted July 10, 2009 Further to my rather smug "I've cracked it" report earlier, I haven't! I've just put another set of seals and pistons in the rear caliper and bled it out again and there's still no sign of any pressure. I've now worked on this every day since last saturday! I've been very patient and avoided pumping the pedal and emulsifying the fluid, but I'm absolutely at a loss as to why I can't generate any significant brake pressure. I've read all the various posts on here, so I guess there's not a great deal anyone can put forward. Anyone want to buy a 2001 Rev3? Excellent nick, needs slight attention to the back brake... Graham Quote Link to comment Share on other sites More sharing options...
stork955 Posted July 10, 2009 Report Share Posted July 10, 2009 I recently went through this with the Techno. The only way it happened for me was to remove the entire system off the bike (which meant I had to let the top shock mount go) and bleed it up on the bench. I put the m/cyl in the vice at an angle that allowed the air to get up into the cylinder, Caliper low (on the floor) with its inlet pipe facing up, A syringe acting as the reservior and suspended above the m/cyl. The method I use to bleed most bike brakes is to very gently just "crack" the piston a couple of mm, say 1/8 inch and let it back out. You will see a small air bubble appear in the reservior from this. Tap on the fitting etc with the handle of a screwdriver. Repeat. Repeat. Etc. Once the m/cyl is primed up and I have a semblance of a pedal/lever only then do I bleed the caliper. Dont let it run out of fluid... Then refit the lot to the bike. I have vacuum bleeders etc and none of them worked on the Beta. HTH Cheers, Stork Quote Link to comment Share on other sites More sharing options...
grahamjayzee Posted July 11, 2009 Report Share Posted July 11, 2009 Hi Stork, Tried this too! I think I'm going to have to concede defeat and get a bike shop to do it. I've spent time every day now since last saturday on this and whilst I got some pressure today, it's not enough to lock the wheel. Is this just a Beta issue? I've NEVER had problems like this with road bikes; as most trials bikes use AJP gear, do the others suffer? I will chop the Rev3 in against any bike with working brakes! I can't face this again some time in the future. Graham Quote Link to comment Share on other sites More sharing options...
betarick Posted July 11, 2009 Report Share Posted July 11, 2009 Best way to bleed rear brake i found was to remove rod from pedal and work by hand! you seem to get more rear master cyl piston movement and will empty reservoir with 1 stroke of piston so fill reservoir after every stroke! hope this helps Quote Link to comment Share on other sites More sharing options...
stork955 Posted July 11, 2009 Report Share Posted July 11, 2009 Gday Graham , Im not sure if this has been covered before, but check the transfer port in the m/cyl. This is the smallest hole under the reservior inlet pipe. This was blocked on my bike causing the trouble with the brake in the first place. If this has rubbish in it they will not bleed for love or money. You may need to gently prise the rubber inlet fitting out to get at the hole, then check it with a fine wire. Remove the piston etc first. Cheers, Stork. Quote Link to comment Share on other sites More sharing options...
ming Posted July 12, 2009 Report Share Posted July 12, 2009 Shame there seems to be a few areas (stator, water pump corrosion and now rear brakes) where Beta falls down, otherwise it's a cracking bike. I guess there are always going to be weak points to any trials bike though? Anyway, back on topic: I have put new pads in the rear brake when I bought the bike (Y2K Rev3) and although I have great braking with the wheel being easy to lock but no binding I have a concern with the rear pedal - there is no free play before it operates and twiddling the adjustment rod does nothing apart from make the pedal even lower and then you can't get enough leverage to lock the wheel - I would like to raise it but if you lift the pedal it moves about 2 inches with no resistance. I had th exhaust off to see if there was another adjuster hidden behind the frame but there doesn't seem to be a way of manually adjusting the height of the pedal or the free play before it bites - any suggestions? Quote Link to comment Share on other sites More sharing options...
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