Cotton eyed Joe Posted February 25, 2004 Report Posted February 25, 2004 K I put on new stainless braided lines yesterday, tried to bleed them, nothing. I tore my master cylinder apart, and it was kinda dirty from me polishing it, cleaned it, put it back together. Nothing. Went and bought a rebuild kit from the Yamaha crooks. $29.95. Nothing. Put stock lines back on. Nothing. I did buff and polish my cylinder, and I think I may have buffed the surface that mates to the banjo bolt. I put it in the mill as true as I could get and milled it down about .010". Then we started to get a slight squeek of air escaping. We checked all the fittings, tightened everthing down. Nothing. We can however put a thumb over the master cylinder hole, pump up and release the air out of the cylinder, and get enough fluid pressure to spray DOT4 all over my face twice. What the hell could it be? We've tried the stock lines, we've tried one line at a time, and nothing works. The only way we ever get pressure is when we put a thumb over that master cylinder opening, and "bleed" the air out, then it feels like it "pumps up" Any help would be appreciated, as Dumont is just around the corner. Thanks. Quote
. Posted February 25, 2004 Report Posted February 25, 2004 so its not bleeding down through your lines but the master cylinder is checking out fine? The fluid go down at all when you try bleeding them? Try getting those stainless lines back on there and when you crack the bleeder on the calipers see if it pushes air out of there. Sounds like a blockage. Try to see if you can blow air through your brake lines and feel if it flows through there. Get one of those little vacuum cups that you connect to the bleeder. They work pretty good. Quote
Cotton eyed Joe Posted February 25, 2004 Author Report Posted February 25, 2004 so its not bleeding down through your lines but the master cylinder is checking out fine? The fluid go down at all when you try bleeding them? Try getting those stainless lines back on there and when you crack the bleeder on the calipers see if it pushes air out of there. Sounds like a blockage. Try to see if you can blow air through your brake lines and feel if it flows through there. Get one of those little vacuum cups that you connect to the bleeder. They work pretty good. Thats another thing....We get the occasional "spit" of fluid, but we are having problems with both stainless and stock lines. We have tried 4 different lines, and all act the same. After the last 15 minutes of so of pissing around with this thing, I'm beginning to wonder if the master cylinder isn't just junk. I don't know why it would be. No scarring in the barrel. The ports in the ressy are clear. I'll go check those lines though just to make sure. I'll be back in 10. Quote
Cotton eyed Joe Posted February 25, 2004 Author Report Posted February 25, 2004 Air passes through the lines and brakes just fine. I can't get it to pump up at the master cylinder now. I've taken it apart, and looking at it, there arent any marks in the bore at all. It looks clean as hell in there. All new guts this morning. It just acts like its passing one of the cups. Like the primary cup isn't sealing all the way. The rebuild kit did nothing for my problem. No fluid leaks out of anywhere on this thing either. It seems to be tight as a drum, but on the pressure side of things, it acts like the primary cup isn't doing its job. But how? Its bigger than the bore. I have to compress it to get it in. Quote
DUNEDEMON Posted February 25, 2004 Report Posted February 25, 2004 As stated earlier a "Mity Vac" vacum pump will makt the job easier. I had a similar problem after installing my front lines, attached the pump to the bleeder on the caliper (one at a time) open the bleeder, don't touch the brake lever, give a few pumps on the mity vac and presto - brake fluid, I would try this before swapping master cyls. Especially if the master was working fine before the installation of the new lines. Quote
pimp559 Posted February 25, 2004 Report Posted February 25, 2004 My friend just went through this on his shee. We did all the same shit your talking about. Finally we bought a nice master cylinder off ebay for like $25 that came with lever and cap. Would really like to know if the vacpump works. Keep us posted, might have to buy one if it works for you. I'm willing to bet the pump works since your getting pressure out of the master cylinder. Obviously the lines are dry and doing it manually with out the pump will take for ever to get any fluid out of the bleeder valve. Reality is you probably didn't need the rebuild kit just the right tool. Quote
Cotton eyed Joe Posted February 26, 2004 Author Report Posted February 26, 2004 Here's what my dad did while I was on the phone with Banshee370: He had to use a screwdriver to press the plunger in further than what the lever would allow. Then apparently after there was no more air in the master, in front of the primary cup, we could bleed them, pump them up, and now they stay. I will check them again tomorrow, and if need be I have the magnum sitting here beside me. Thanks to everyone for the replies. Stan. Quote
MotulMonsta Posted February 26, 2004 Report Posted February 26, 2004 When I put steel brake lines on my shee, it took a hell of a lot of fluid to get it to bleed, I ended up using a syringeand injecting it into the lines before I reconnected them. It took a while but I got it to work. Quote
Meat Posted February 26, 2004 Report Posted February 26, 2004 Nothin beats a MityVac. Hooking up some clear tubing (like the stuff used with aquariums) on your bleeders and manually sucking the fluid down the brake lines also works. Just keep an eye on the clear tubing so your not drinkin' brake fluid. It makes yer lips numb Quote
. Posted February 26, 2004 Report Posted February 26, 2004 on my stock brake lever theres a screw that you can adjust how far you can press the plunger in. I dont know what year shee's they did this with, but I know a kid that has a 2002 and his brake lever doesnt have the screw. Maybe the screw wasnt in far enough? Maybe somehow it was creating a vacuum at the master cylinder with the lines on that when you let go of the brake lever it just sucked it back in, and when using the screwdriver it broke past that barrier. Good to see you got it working though. Quote
Cotton eyed Joe Posted February 26, 2004 Author Report Posted February 26, 2004 on my stock brake lever theres a screw that you can adjust how far you can press the plunger in. I dont know what year shee's they did this with, but I know a kid that has a 2002 and his brake lever doesnt have the screw. Maybe the screw wasnt in far enough? Maybe somehow it was creating a vacuum at the master cylinder with the lines on that when you let go of the brake lever it just sucked it back in, and when using the screwdriver it broke past that barrier. Good to see you got it working though. We turned the screw in, but then we noticed that it wouldn't let the piston all the way back out again. So thats why we ended up pushing on it manually. I'll invest in one of those My-Teeee-Vaks. Brakes are something I've never had to work on like this. I disassembled the brakes, polished them, installed new seals etc. This just kicked my ass. 2 days a quart of DOT4 later... Thanks for the tips guys. I'm definitely NOT going to forget how to do this next time. I've washed my hands a dozen times, and they still feel like they have brake fluid on them Quote
clint Posted February 27, 2004 Report Posted February 27, 2004 when did the same yours is doing, i just squeezed the lever all the way back to the bars, put a wire tie around it and let it sit over night. bleeders closed and cap loose.worked like a charm. Quote
lucky13 Posted February 27, 2004 Report Posted February 27, 2004 mity vac is the only way to go it worked for me Quote
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