kibsy Posted April 3, 2009 Report Share Posted April 3, 2009 hi, my front brake suddenly went really stiff , i released all the pressure by letting all the fluid out, i started to bleed the brake (pipe on nipple into tub of fluid, nipple open then lever in, nipple closed, lever out, then repeated.) i noticed that there were tiny bubbles flowing out from the holes at the bottom of the master cylinder. then i noticed that fluid was dripping out of the master cylinder at the back like where it meets the brake lever. i then took the valve out and checked the seal for niks, there were none, i have no idea what to do, any help would be much appreciated as its beautiful weather at the moment and i cant ride regards james Quote Link to comment Share on other sites More sharing options...
lowbrow Posted April 5, 2009 Report Share Posted April 5, 2009 Sounds like you didn't have enough free play at the lever end so the fluid couldn't return to the master cylinder. Had you adjusted the stop to bring the lever back closer to the bars without adjusting to maintain the free play? If the seals are okay I'd put it all back together. Refill the master cylinder, put the bars on full left lock (to make the master cylinder the highest part of the bike) and keep squeezing the lever gently until no more tiny bubbles appear from the bottom of the reservoir, and you should be back in business. Top up the reservoir and have fun! Quote Link to comment Share on other sites More sharing options...
ramjet Posted April 7, 2009 Report Share Posted April 7, 2009 Hi Mate I'm new to trialling but have had road bikes for yonks!! Front Brake on my 2003 sherco 290 went spongy a few weeks ago ,so changed the fluid. Anyway to cut a long story short I had an absolute nightmare bleeding the sod. Eventually managed to bleed the brakes using a vacuum pump (connect a tight fitting tube to the bleed nipple and draw the fluid through the nipple taking care to keep the fluid level topped up) I used a large syringe to keep topped up. One thing I will say is that I was still getting a constant stream of bubbles from the bleed nipple even after drawing through about 150ml of fluid and eventually found that air was coming through the threads of the bleed nipple!! I used ptfe liquid thread sealant to seal thread and after that it was happy days. I know it's a bit long winded but I could not believe the problems that I had with such a relatively straightforward and basic system compared to my fireblade which I have never had any problems with!! I would'nt like anyone to have the same nightmare that I had!!! Best Regards Quote Link to comment Share on other sites More sharing options...
ham2 Posted April 8, 2009 Report Share Posted April 8, 2009 Hi Mate I'm new to trialling but have had road bikes for yonks!! Front Brake on my 2003 sherco 290 went spongy a few weeks ago ,so changed the fluid. Anyway to cut a long story short I had an absolute nightmare bleeding the sod. Eventually managed to bleed the brakes using a vacuum pump (connect a tight fitting tube to the bleed nipple and draw the fluid through the nipple taking care to keep the fluid level topped up) I used a large syringe to keep topped up. One thing I will say is that I was still getting a constant stream of bubbles from the bleed nipple even after drawing through about 150ml of fluid and eventually found that air was coming through the threads of the bleed nipple!! I used ptfe liquid thread sealant to seal thread and after that it was happy days. I know it's a bit long winded but I could not believe the problems that I had with such a relatively straightforward and basic system compared to my fireblade which I have never had any problems with!! I would'nt like anyone to have the same nightmare that I had!!! Best Regards The most commonly practiced remedy on these forums would be ''reverse bleeding'' where you use a large syringe full of fluid and force it in the nipple up to the master cylinder...works a treat. I'm a mechnical doofus so I need all the tips I can get. If you ever have a problem with your bike I would recommend you do what I do (don't reach for the toolbox,reach for the keyboard), do a search on the Sherco forum first or post up a question....loadsa practical, helpful people on TC. Sometimes there's a guy on the other side of the planet who knows exactly what your problem is, yet your local bike dealer talks a foreign (Yorkshyer?)language. Quote Link to comment Share on other sites More sharing options...
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