Am I wasting my time bleeding?

[Guest]

So I've done a complete brake rebuid (new SS lines, several new pistons, new seals and o-rings) Before doing this the brakes worked fine so there should be nothing wrong with the MC front and back. I did the pump, hold, open, close, release method and the back brakes feel great. The fluid in the front MC hasn't budged even after having the handle tied all night.

My question is when I bought the SS lines for the front I had to estimate the front line going to the banjo and ended upo getting it to long. If you look at the picture I've "made it work" as far as the connections, but it does go up and then back down to the middle banjo. Is this going to make it difficult to bleed? I would rather not buy the mighty pump since manual bleeding isn't bad, but if the line will work and I need help with the pump I will. If not, then I should just buy the smaller line.

Thanks,

[barnbiketom]

try eliminating that upward loop somehow temporarily. I bet there's an air bubble trapped. or perhaps get a shorter hose would be the thing to do? once the air is out, you could wrap it all over.. just getting it out is the problem.

[claygs750e]

Well I took the line off the front so the MC has fluid and it still doesn't move without a line even attached so it looks like something is going on with the MC. I don't have a pair of snap ring pliers to take it apart so not sure what I need to do. Shouldn't fluid come out of the MC when I pull on the handle even if there's no line attached?

[claygs750e]

Ok so I've bought a completely new front MC and rerouted the front line so it doesn't go upward any longer. I borrowed my friends mighty pump and I'm not getting any bubbles on either front caliper, but I still have to squeeze almost all the way before the brakes engage. Even when doing that if I push the bike hard the front wheel will move. I'm not sure what to do at this point since the lines, front MC, seals and O-rings are all new with no air in the lines.

[bwringer]

Couple of things to throw out there:

Did you bench bleed the MC? This is needed to get the last few air bubbles out of the MC if it's been dry or it's new. You can do this on the handlebar by removing the lever and pushing the cylinder in all the way with something blunt.


Sometimes new seals are a bit tight. When you pull the lever, look at the pads -- do they move in and clamp down on the brake disc? When you let go of the lever, they should "relax" a bit, but if they retract back to the original starting point, this may be the problem. Are you using OEM Suzuki seals and pistons?

[claygs750e]

I didn't do any type of bench bleed. I had the same problem with the OEM front MC and because I wanted to replace it anyway I didn't do much troubleshooting with the old MC and went ahead and bought new. But even with the new one it's better, but having the same problem pretty much which makes me think something else is going on. I did buy the OEM seals and orings.

[bwringer]

PM sent...

[claygs750e]

After multiple tries and with my brother-n-laws help somehow it feels much better now. Not sure if there was air in the lines or me just being an idiot. Thanks guys for all the help

[MK3Brent]

If you don't already, get a proper vacuum system to evacuate brake lines.

If not, take it to your local shop and have them bleed the lines with their vacuum system... should take 5 minutes.

Hope you're happy with your results you posted in post #8.

[Leo]

I have a somewhat similar brake bleeding newbie question on my 79 GS850G. I purchased Rennsport stainless brake lines and installed them on my front brakes. I filled the master cylinder with fresh DOT4, attached my mityvac, built up pressure to about 20, cracked the bleeder. Took quite a while until I got any fluid out into the mityvac catch container. Despite a lot of back and forth didn't end up with much fluid in the mityvac container. But.......my brake pressure feels great and the brakes seem to engage just fine. My question is - am I done? or should I continue bleeding until I get more brake fluid to run through the system?

[MK3Brent]

What I've learned, is the cleanliness of the bleeder screw makes a big difference.

You can tell when they're dirty, when you don't immediately get fluid/air out of the screw with just a 1/4 turn from tight. If you have to back out the screw a lot before you start seeing fluid... then you're going to be sucking air back in through the threads.

Are your bleeder screws doing this?

Are you bleeding the anti-dive bleeders first? (Assuming you still have them?)

[Agemax]

wrap some PTFE thread tape around the threads on the bleeder screws. that will prevent any air being sucked in through the threads.