Member Contributer gig Posted May 10, 2018 Member Contributer Share Posted May 10, 2018 Have a non linked system, with double banjo at master direct to each caliper, filled from dry. If I zip tie my front brake lever, I get a very firm lever first day, second day have to adjust the lever out to get same firmness at the same position, which leads me to believe I have air trapped somewhere. Logic tells me that the air is not forced up or down with pressure from overnight zip tie, but that the air pocket or pockets are dispersed into microscopic bubbles throughout the fluid, and then after a day or two reforms into a larger pocket or pockets again. I've bled at the caliper by cracking the banjo bolt, bleeder valves, and have taken the calipers off and hung high at different angles. Any thoughts? Link to comment Share on other sites More sharing options...
Member Contributer KevCarver Posted May 10, 2018 Member Contributer Share Posted May 10, 2018 Do you have a vacuum bleeder? I like the ones that are compressor powered. I have a similar braking setup with SP1 calipers and 2 direct lines. Edit: (Oh, I lied! Really they are F4i calipers, but physically identical to SP1 except for color...) I've never really understood the physics behind the zip tie thing either. Your theory sounds more plausible to me. I don't have one, but there are big syringes that people use to push the fluid up from the bleeder into the reservoir. Link to comment Share on other sites More sharing options...
Member Contributer Grum Posted May 10, 2018 Member Contributer Share Posted May 10, 2018 Would it be possible your master cylinder is pitted or the piston cup worn? Link to comment Share on other sites More sharing options...
Member Contributer sfdownhill Posted May 10, 2018 Member Contributer Share Posted May 10, 2018 Gig, I have the same problem, and have tried all the same things you have. I’ve probably bled more than 3 bottles of Galfer fluid through my front brakes trying to get them to firm up. My system is a CBR600F4i master cylinder pushing RC51 SP2 calipers through braided hoses. I’m putting up w it because the firmness, lever position and braking performance are good, just not great. I was visiting RVFR, who has a very similar setup to mine - F4i master, F4i calipers, braided hoses, and his are frickin’ rock solid. I was using Chinese levers from eBay, and switching to OEM levers helped a little. ASV levers are a litttle better than OEM, but none of the lever solutions makes the front brake ‘corrrct’. Hope someone can chime in w a solution. Link to comment Share on other sites More sharing options...
Member Contributer Cogswell Posted May 10, 2018 Member Contributer Share Posted May 10, 2018 18 minutes ago, KevCarver said: I don't have one, but there are big syringes that people use to push the fluid up from the bleeder into the reservoir. Phoenix systems makes a reverse bleed kit. I don't own one but have thought about it - it seems intuitive to push the fluid (and hence the air as it likes to rise up through the fluid) up and out to the M/C. Maybe do an on line or youtube search for people that have used them. I've seen them for sale on Amazon previously. YMMV. https://www.brakebleeder.com/products/best-sellers/v5-diy-reverse-brake-bleeder/ Link to comment Share on other sites More sharing options...
Member Contributer KevCarver Posted May 10, 2018 Member Contributer Share Posted May 10, 2018 13 minutes ago, sfdownhill said: Gig, I have the same problem, and have tried all the same things you have. I’ve probably bled more than 3 bottles of Galfer fluid through my front brakes trying to get them to firm up. My system is a CBR600F4i master cylinder pushing RC51 SP2 calipers through braided hoses. I’m putting up w it because the firmness, lever position and braking performance are good, just not great. I was visiting RVFR, who has a very similar setup to mine - F4i master, F4i calipers, braided hoses, and his are frickin’ rock solid. I was using Chinese levers from eBay, and switching to OEM levers helped a little. ASV levers are a litttle better than OEM, but none of the lever solutions makes the front brake ‘corrrct’. Hope someone can chime in w a solution. You might be better served with an SP1 or F4i master, as the F4i and SP1 calipers have identical pistons. SP2 and 600RR match up. Gig, are your MC and calipers properly matched? Also, what Grum said. Could be an issue with the MC itself. Link to comment Share on other sites More sharing options...
Member Contributer VFROZ Posted May 10, 2018 Member Contributer Share Posted May 10, 2018 I have the 600RR master with SP2 calipers and it’s fantastic. The master is sometimes very hard to bleed, a tiny bubble gets stuck in the banjo section, more so if you have twin lines. The only way I’ve ever found to be successful was to fill and seal the master, then remove it from the handle bar and tilt it so the banjo is the lowest point. Now shake it while you operate the lever rapidly to get rid of any bubble that is still there. Im not sure what pads you have, this can also make a huge difference. Keep away from organic pads if you want great braking in any situation. Link to comment Share on other sites More sharing options...
Member Contributer gig Posted May 10, 2018 Author Member Contributer Share Posted May 10, 2018 I have F4i master and calipers. I did reverse bleed up from caliper with a large syringe from tractor supply "when I picked up EPDM hose at 1/10 the cost from on line parts store" for rear brake reservoir. Also have mighty vac. which I did not use. I bought the master off eBay, so possible pitting or wear, I did not disassemble as it literally looked brand new. The fact that it takes a day to notice any softening, and then goes to second setting and stays there, i guess i could zip tie and then just flush a full bottle through the lines to flush out then any contaminated fluid Link to comment Share on other sites More sharing options...
Member Contributer gig Posted May 10, 2018 Author Member Contributer Share Posted May 10, 2018 26 minutes ago, VFROZ said: I have the 600RR master with SP2 calipers and it’s fantastic. The master is sometimes very hard to bleed, a tiny bubble gets stuck in the banjo section, more so if you have twin lines. The only way I’ve ever found to be successful was to fill and seal the master, then remove it from the handle bar and tilt it so the banjo is the lowest point. Now shake it while you operate the lever rapidly to get rid of any bubble that is still there. Im not sure what pads you have, this can also make a huge difference. Keep away from organic pads if you want great braking in any situation. I like this idea. I was always told never to shake brake fluid bottle i will impart air into the fluid, maybe rocking while tapping bajo? Vesrah RJL pads, great bite cold or hot, no fade FYI Pazzo levers lots of adjustment Link to comment Share on other sites More sharing options...
Member Contributer rangemaster Posted May 10, 2018 Member Contributer Share Posted May 10, 2018 28 minutes ago, VFROZ said: Keep away from organic pads if you want great braking in any situation. Truer words were never spoken. I tried organic, they were ok until the first ride in the wet. I almost would have done better dragging my feet. Worthless in the rain. Link to comment Share on other sites More sharing options...
Member Contributer RC1237V Posted May 10, 2018 Member Contributer Share Posted May 10, 2018 1 hour ago, Cogswell said: Phoenix systems makes a reverse bleed kit. I don't own one but have thought about it - it seems intuitive to push the fluid (and hence the air as it likes to rise up through the fluid) up and out to the M/C. Maybe do an on line or youtube search for people that have used them. I've seen them for sale on Amazon previously. YMMV. https://www.brakebleeder.com/products/best-sellers/v5-diy-reverse-brake-bleeder/ +1 I bought the plastic version, when I could not bleed my clutch line. Tried for a week. I even built a positive stop, so the slave cylinder was like a brake caliper, rather than spring loaded. I was ready to give up, then tried the Phoenix. Reverse bled in 5 minutes and has been perfect ever since. The bubbles naturally rise, so reverse bleeding seems like the best choice. You can also vacuum bleed with the phoenix as well. Someday I will get the $350 metal version, but this plastic one still works fine, so I will spend the cash on parts! Link to comment Share on other sites More sharing options...
Member Contributer RC1237V Posted May 10, 2018 Member Contributer Share Posted May 10, 2018 Just remembered - I have also heard that tapping the caliper and brake levers with a screwdriver (handle end) while bleeding helps release trapped air bubbles............ Link to comment Share on other sites More sharing options...
Member Contributer gig Posted May 11, 2018 Author Member Contributer Share Posted May 11, 2018 23 hours ago, VFROZ said: The only way I’ve ever found to be successful was to fill and seal the master, then remove it from the handle bar and tilt it so the banjo is the lowest point. Now shake it while you operate the lever rapidly to get rid of any bubble that is still there. VROZ, it worked. It got me about half way there. i start out at setting 3, next day 4, ends up on 5. Firmed up to 4 bleeding the master as you suggested.Going to try my theory and sip tie overnight, bleed right away to see if it will flush any remaining pockets and or keep that firmness. Thanks, you've have been big help recently, Ill put your check in the mail... Link to comment Share on other sites More sharing options...
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