I have tried using the vacuum tool, using the speed bleeders, using good old fashioned gravity feeding, you name it.. i can't get this thing to feel 'normal' Master cylinder - brand new RCS19 calipers - 2015 GSXR-600 Brembo 4 piston with OEM rebuild kits just installed, zero miles since install lines - galfer GP style 2 into 1 should i be bleeding the longer distance one first? Like on a car? Going back and forth? why am i such an idiot?
Are the lines completely dry? I think I had to start with the master to build up some pressure first before bleeding from the furthest caliper. You may also need to bleed at the banjo bolts on the master as well. I am a total perfectionist when it comes to bleeding and brake feel, so this is what I do. 1. Attach tubing to the bleeder valve being bled. 2. Use a tubing clamp to ensure the tubing is snug against the bleeder. 3. Using a small syringe, dispense clean fluid into the tubing you just installed so that air doesn't have a chance to come through the bleeder when cracking it open. 4. Pressurize system via pressing on the brake lever, then crack open the bleeder slightly. There should still be some resistance in the brake lever throughout the process. 5. Close the bleeder BEFORE reaching the end of brake lever travel so that the system is always pressurized to push air out. 6. Repeat eight hundred times. If I had a compressor, I'd probably start with the compressor to get most of the bubbles out and then just finish it off the regular way to make it perfect.
I would start at the bleeder nipple of the RCS19 to get any air out of the M/C first. The air there may be getting in the way of fluid flowing down the lines into the calipers. Lots of lever squeezing and patience sometimes is what it takes to get a braking system to reprime itself. Been there and done that and I feel your pain.
Like a ktm clutch, I usually start by biting the bullet, open MC bleeder and load up a syringe with brake fluid. Works every time vs the pain of the odd time a radial Mc doesn’t want to start feeding steady fluid.
Depending on the position of the holes in the banjo bolts relative to the brake line, sometimes air can get trapped in the head of the banjo bolt itself. You can bleed those by very slightly loosening the banjo bolt while pulling the brake lever. It can be very messy so be certain to protect any nice surfaces and clean well after you tighten it up again. I have had this happen a few times but not often. I also seem to remember someone posting a picture on here that showed his calipers were mounted on the wrong side, which would put the bleeder on the bottom. I truly doubt this is your issue, but you never know.....
If we have a tough one with a car we reverse bleed it. This usually has to be done with clutch slave cylinders but the principal is the same. Lower the fluid level in the master and use some sort of device filled with brake fluid , syringe works. Hook it up to one of the caliper bleeders and crack it open, then force the fluid backwards through the system. The air naturally wants to rise, and I personally think that's the reason most people have issues.
i like the syringe method. i wonder if that will work with my speed bleeders. i've been told there are check valves inside them that may prevent back feeding.
Along these lines, removing the caliper and forcing the pistons all the way back into the bore sometimes helps dislodge some trapped air. But it sounds like you have more than a little air getting in somewhere. Hope the seals didn't get nicked or pinched on installation.
My method to get a new master working is messy but it works. Put a large towel under and around the master banjo and have a spray bottle of water close by, you'll need it. Remove the banjo from the master and put your thumb over the opening and pump the lever. Three or four pumps and the master is full and working. Now, clean up the mess and reinstall the banjo....proceed to the calipers.
Perhaps, I never tried it that way. New (or rebuilt) masters are so infrequent for me that it never occurred to me to try. Don't know why folks are so scared of brake fluid on plastic or paint. As long as you rinse it off right away it's not a big deal.
i have a similar issue with the vacuum bleeder. I have teflon tape around the banjo bolts and the bleed screw. I have a clamp on the bleeder hose. It will hold vacuum pressure, so i assume the seal from the bleed screw to the vacuum pump is not letting air in. When i open the bleed screw, there is a steady flow of small air bubbles. I've ran a can of brake fluid through and the bubbles remain and the mushy lever feel (KX 450 with a performance engineering brake caliper and a motostuff pro-lite brake line). I walked away from it for the day and will try a syrnge next to push fluid up.
Get speed bleeder bolts. I wrecked myself on this last winter until I finally discovered speed bleeders. They’re the easiest things in the world and you’ll be done in a few minutes. Once you pop them on you just pump the brake until all the air is out. Also be sure to bleed from the master cylinder as well as the calipers.
Use a vacuum bleeder on the calipers and hold the brake lever to the bar (or pump, or both, it’s been awhile). I found this to be the fastest way to get a completely dry system filled. Edit: never mind this ^. Take the master off so the bleeder is the highest point. Tap the calipers and make sure their bleeders are the highest point too. Tap the lines to get the bubbles up. Once you’ve got pressure it’s just a matter of bleeding it until it’s right. Try taping the lever so there’s pressure in the system overnight and then re-bleed again. I always start at the furthest caliper and then the master last.
I can't ever remember seeing teflon tape on the threads of any braking system in the m/c industry in a aftermarket or OE situation. I believe pressure fluid carrying lines and their fittings are built with tapers on the male and female ends to seal correctly. And hence teflon tape is not needed, but what do I know I'm not an engineer but I played one on TV?
Bleeding the master with its bleed nipple and its banjo is the first thing I do. You are likely wasting time and fluid if you dont.
