Abso-freakin-lutely STUMPED

[Escobarclan]

Has anyone dealt with this before?

My boy and I are SO CLOSE to finishing this bike, 1982 GS1000s Katana



The front brakes were a little spongy, so I went to bleed them. I started with the Anti-dive bleed valve, then the brake on each side just like the book says. Some crud and a little air came out, when I pulled a genious move and pumped the master cylinder dry, pulling in air. Ok, no problem, dealt with this before, so I kept the master cylinder filled and kept bleeding.



I've bled everything right but the brake handle almost bottoms out, barely setting the brakes. I've gone through 3 bottles of fluid (yes, DOT4), and still nothing but pure fluid on both sides.

I'm not sure what to do, can anyone help?

[Zooks]

You may have damaged something in the master when you ran it dry. Do they actually build any pressure or is it just pumping straight through?

[chiphead]

Take a good look at how your hoses are routed then crack and bleed the actual union bolts where the hoses attach to the master cylinder and other junction points starting from the top down, then re-bleed he entire brake system. I have seen air bubbles trapped at the union bolt junctions which will not bleed through under normal brake bleeding procedures.

[davey boy]

Hi there,the bike looks good. I had a similar problem years ago,the whole system had been dry for some time(for cleaning),after assembly i spent days trying to bleed,asuming there is no damage try removing the calipers whilst still connected to the system and if possible disconnect the joint from the frame,the idea is to raise the system to a similar hight of the resivour(a few inches below),put some flat metal in the calipers and bleed as normal,i put a table in front of the bike and bleed the calipers on that,im not sure if it was luck but within half an hour the brakes worked fine,i hope this is of some help,it worked for me,good luck.

[bwringer]

Crikey, go down to the auto parts store and get a vacuum bleeder already!

For about $25 or less, you'll end these sorts of problems forever. I've never had any luck pushing more than a few tiny bubbles of air through a motorcycle brake system with manual pumping. With a vacuum pump, it's a 5 minute job.

[Steve]

With a vacuum pump, it's a 5 minute job.

And that's to do all three calipers. :shock:

OK, maybe six minutes because of the anti-dive. 8-[

When you go to the auto parts store, here is what you are looking for: Mityvac.
Plastic versions (perfectly adequate for home use) run $30-35, metal versions are about double that.

.

[tone]

20 odd year old stock rubber hoses will be expanding as soon as pressure is built up which may account for the lever coming back to the bar :shock: braided steel is the solution here

bleeding the brakes as normal with the calipers held higher then the master cylinder will help things along also cable tie the lever back to the bar & leave overnight & giving the calipers & lines the occaisonal tap before re bleeding will help dislodge any trapped air :-D

[Cassius086]

Yessir, go get a vacuum bleeder!!

Beautiful bike by the way, if I have not already complimneted you and your son! :-D

[Escobarclan]

Thanks guys, I didn't even think of a vac kit. First I'll try the suggestion of taking off the calipers and raising them, or at least turning them over, the anti-dive would have to be taken off the forks, and I don't want to mess with that. I've already loosened the union bolts with no success there.

The brakes do apply, the handle has a good bit of resistance, but bottoms out, you can pump it and it builds up a little.

[Shin-Ken 1074]

Great work on the project she looks fine indeed, got here late but your brake bleed problem should be on the way to being resolved by the look of it. Good to see another TDK (Target Design Katana) being put back on the road, go team. Please please please photos of the finished project?

[chef1366]

Braking is over rated. *
Take off the M/C cap and lever. Push the piston in with a phillip screwdriver and watch all the tiny bubbles rise out of the M/C. The brake lever doesn't push the piston all the way into the M/C to get that last bit of air out.
Too bleed out the M/C take off the line leading into the union from the M/C and dunk it into the resevoir and push the piston in with the screwdriver.

Sing with me
Tiny bubbles.............

[Escobarclan]

Wow, you guys are great.

It is really cool to be part of this forum, where everyone shares this kind of info.

I tried using a vac. Bought it at the parts store today, but it didn't help any. Also I called a friend and he told me to try shooting brake fluid into the bleed valves to push the air up, and it actually helped a little.

I'm gonna try the suggestion about pushing the M/C piston in further to get more air out. Is it possible that the M/C piston could be leaking air in??

Also thanks for the compliments on the bike, my boy is getting a kick out of em' since he provided most of the elbow grease. When she's done I'll post some more pics.

[TheCafeKid]

...in my wine...:-D

[focus frenzy]

first, stop posting pics of the bike! this is a family semi-friendly site and pictures of a hot sexy naked bike is pornagraphic!!! LOL

the anti dive system Suzuki used is good for a mushy lever and is very hard to get remotly any where near what the lever is like without it.

one of the problems is that loop up and over to the anti dive unit. it is a air pocket magnet.

also little pockets of air like to stick around in the master cylinder and changing around the angle of it while lightly pressing and reliesing the level will work them out.

a great many 82 and up bikes run around with the anti dive disconnected and or blocked off for a good reason.

[Zooks]

a great many 82 and up bikes run around with the anti dive disconnected and or blocked off for a good reason.

It's also common for guys that use the later model front ends on older bikes to blank them off as well.