experiment70 Posted May 1, 2008 Report Share Posted May 1, 2008 I'm having an issue (which is a euphemism for a screaming tantrum) installing a new rear caliper on my '03 280 TXT Pro. My previous issue involved a broken bleeder valve in the old caliper; it has been replaced with a brand new caliper. The old caliper and the rear brake system were not violently damaged, and worked fine when removed. I received my new caliper, bolted it up, and went to bleed it. I cannot establish any pressure in the brake system. I have used a syringe to push fluid from the caliper towards the reservoir; I can't seem to get any fluid to move into the reservoir. I have pulled fluid from the caliper; I can't seem to make the reservoir level drop. I have pumped the brakes and cracked the bleeder valve; I can make a small amount of fluid and a lot of air come out of the bleeder valve, but I can't get any pressure. In desperation, I forced some fluid from the reservoir towards the caliper using a syringe; fluid emerged from the bleeder valve, and I had one stroke of the brakes with pressure, and then nothing again. I took the caliper back off and, again using a syringe, tried to fill it with fluid before reinstalling. Still no luck. Either there is air still trapped in there, or there is a leak somewhere. And I don't know why there would be a leak now, when there wasn't one before. I haven't ridden in 6 weeks and I'm going nuts. Is there something I'm missing? Am I doing something wrong? Do the trials gods hate me? I am grateful for any advice I might receive. Thanks, Forrest Quote Link to comment Share on other sites More sharing options...
shercrazy Posted May 1, 2008 Report Share Posted May 1, 2008 sounds to me like your master needs attention, my beta did the same thing and i had to order a rebuild kit for it, if that leaks it is continuously breathing air every time you push on the pedal, or maybe some dirt got in there from the cylinder relaxing all the way when you took the caliper off and released the pressure, i'd clean it real good and try it again and if it fails order a rebuild kit......................john Quote Link to comment Share on other sites More sharing options...
experiment70 Posted May 1, 2008 Author Report Share Posted May 1, 2008 sounds to me like your master needs attention, my beta did the same thing and i had to order a rebuild kit for it, if that leaks it is continuously breathing air every time you push on the pedal, or maybe some dirt got in there from the cylinder relaxing all the way when you took the caliper off and released the pressure, i'd clean it real good and try it again and if it fails order a rebuild kit......................john Thank you for the new idea. I haven't taken apart a master cylinder before; will if be obvious what needs attention when I do? Any tips? Thanks again, I needed a new direction. Forrest Quote Link to comment Share on other sites More sharing options...
jse Posted May 1, 2008 Report Share Posted May 1, 2008 I'm having an issue (which is a euphemism for a screaming tantrum) installing a new rear caliper on my '03 280 TXT Pro. My previous issue involved a broken bleeder valve in the old caliper; it has been replaced with a brand new caliper. The old caliper and the rear brake system were not violently damaged, and worked fine when removed. I received my new caliper, bolted it up, and went to bleed it. I cannot establish any pressure in the brake system. I have used a syringe to push fluid from the caliper towards the reservoir; I can't seem to get any fluid to move into the reservoir. I have pulled fluid from the caliper; I can't seem to make the reservoir level drop. I have pumped the brakes and cracked the bleeder valve; I can make a small amount of fluid and a lot of air come out of the bleeder valve, but I can't get any pressure. In desperation, I forced some fluid from the reservoir towards the caliper using a syringe; fluid emerged from the bleeder valve, and I had one stroke of the brakes with pressure, and then nothing again. I took the caliper back off and, again using a syringe, tried to fill it with fluid before reinstalling. Still no luck. Either there is air still trapped in there, or there is a leak somewhere. And I don't know why there would be a leak now, when there wasn't one before.I haven't ridden in 6 weeks and I'm going nuts. Is there something I'm missing? Am I doing something wrong? Do the trials gods hate me? I am grateful for any advice I might receive. Thanks, Forrest Forrest, Try taking off the rear brake lever and pulling off the M/C boot and make sure the piston comes back to the circlip, it sounds like the piston is not coming back far enough to uncover the bleed hole to the reservoir (usually caused by the plunger rod adjusted in too far). By the way, only fill the reservoir about 1/2 way as it is not vented like the M/C's on the bars and if you are bleeding the system, leave off the cap while doing so. Sometimes, taking off the caliper (rear wheel off bike) and rotating it to allow the air bubble to feed through the bleed screw helps. I'm assuming you didn't "bench bleed" the caliper before installing (adding fluid to the caliper and working the pistons in to remove air from the caliper before fitting the line to it). The two main air trapping pockets are the top of the caliper and the top of the M/C. You may want to take off the M/C and rotate it around and press in on the piston with a Phillips screwdriver to work out the air. Jon Quote Link to comment Share on other sites More sharing options...
experiment70 Posted May 1, 2008 Author Report Share Posted May 1, 2008 Forrest,Try taking off the rear brake lever and pulling off the M/C boot and make sure the piston comes back to the circlip, it sounds like the piston is not coming back far enough to uncover the bleed hole to the reservoir (usually caused by the plunger rod adjusted in too far). By the way, only fill the reservoir about 1/2 way as it is not vented like the M/C's on the bars and if you are bleeding the system, leave off the cap while doing so. Sometimes, taking off the caliper (rear wheel off bike) and rotating it to allow the air bubble to feed through the bleed screw helps. I'm assuming you didn't "bench bleed" the caliper before installing (adding fluid to the caliper and working the pistons in to remove air from the caliper before fitting the line to it). The two main air trapping pockets are the top of the caliper and the top of the M/C. You may want to take off the M/C and rotate it around and press in on the piston with a Phillips screwdriver to work out the air. Jon That's really helpful. Thanks to you both; now I have some new ideas to try tomorrow. Thanks again, Forrest Quote Link to comment Share on other sites More sharing options...
ham2 Posted May 1, 2008 Report Share Posted May 1, 2008 I had a similar problem with a previous bike..I removed the brake pedal and pumped the system with a screw-driver pushing the piston instead. I needed to tilt the bike to some very extreme angles to chase the air out(bike nearly vertical,nose high then rear wheel high). Quote Link to comment Share on other sites More sharing options...
triumphspeedtriplets Posted May 1, 2008 Report Share Posted May 1, 2008 Hi I had the same problem with a JTX250, when i removed the brake line from the master cylinder and blocked the hole with my thumb it had pressure straight away but as soon as i put the brake line back on there was nothing. I tried forcing fluid from the caliper to the master cylinder to remove any trapped air and then into the reservoir bottle, bleeding it at the master cylinder and at the caliper brake line connection and the nipple and eventually i got it working but unfortuanately i dont know how, all i can suggest is keep trying (it took about 6 hours in total). Quote Link to comment Share on other sites More sharing options...
experiment70 Posted May 1, 2008 Author Report Share Posted May 1, 2008 "I hereby direct the Sheriff of this county to remove you from this garage forthwith, and to transport you to the gallows, where before sundown this day you are to be hanged by the neck until dead; your body left to be picked at by the crows, until the Sheriff directs it to be cut down, drug to a shallow grave in unhallowed ground, and buried face down in the dirt. Quote Link to comment Share on other sites More sharing options...
jse Posted May 1, 2008 Report Share Posted May 1, 2008 I think I may have got it (I haven't ridden it yet), and without murdering my bike. I used a combination of the suggestions here: pushing the master cylinder piston in with a hex key, adjusting the plunger rod, maneuvering both the master cylinder and the bike around to help clear air bubbles, and good old fashioned swearing. The problem progressively got better, and I don't know if it was any one thing or a combination of the techniques, but it's better now. I hope it works this weekend, and I appreciate all the help. This has been one of those "learning experiences"...Forrest One of the tricks is to hang the bike up by the back wheel overnight. I've never had to do it but some of my readers swear by it. To this day, I don't have a simple, absolute, sure-way to bleed the rear brake that works every time for every rider but, as you are finding out, it usually takes a combination of small things to make it work. Bleeding the rear brake is a task on just about every model bike from what I've found. One time it's a snap and the next time all hair gets pulled out! Jon Quote Link to comment Share on other sites More sharing options...
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