Brakes won't bleed

[EdgeGrip]

1977 GS750B

I cleaned up and rebuilt my front and rear calipers, I rebuilt the rear master and res, disassembled and cleaned the frot res, and used a GSXR front res on the bike. The front master doesnt appear to be original.

I assembled everything, newer front stainless line (also from a GSXR), and half of the old front stainless line as the new rear line. I filled the reservoirs with fluid, but I cannot get either one to start building fluid pressure. I can bleed them a little bit but it's mostly air pressure with a littl fluid in it. The pads aren't really pressing into the disk. I've tried a million different ways to prime the system with fluid to help it out but nothing seems to be helping.

Like I said a little fluid comes out so I know there isn't a blockage, and all fittings and lines are tight, but I'm at a loss.

Any ideas?

[jwhelan65]

Keep bleeding new lines take a long time, did you rebuild the master?

[greg78gs750]

get a mityvac and be done with it. or a giant syringe from a feed store.

[joejeweler]

If you have a fairly tight fitting bleed hose (at the nipple), and of around 3 feet long, i got the front brake lines (3 in my case) primed by creating a vacume at the far end of the hose,.....with my mouth.

Now, i did make sure to clean the end i was mouthing, and my hose was clear so i wouldn't get a nasty surprise.

But sucking on it much like a straw, only harder, while pumping the front brake lever got the fluid down quickly. Once you have just a few inches showing in the clear hose, you can stop the vacume and working the lever will continue the process. Keep your resevoir fairly full,....don't want air to get back in.

Again, please be sure to clean the hose first,...AND don't continue once fluid is showng a few inches in your THREE FOOT CLEAR HOSE. Use common sense, as i assume NO responsibility for carelessness.

BTW, i found my rear brake single hose was a bit easier,.....can probably skip the sucking there.

.........and yes,.....i did syphon gas occassionally when i was younger,.....and THAT is way less fun without a master cylinder helping it along! (or the syringe type today)

get a mityvac and be done with it. or a giant syringe from a feed store.

Hehe,....just call me mityJoevac!

[JimmyR]

Check the bolts that join the brake halves together and make sure they are engaging properly. They may have flat edges that need to be the right way around.

FWIW I had a Mityvac - until I broke it. It didn't last very long.

[EdgeGrip]

I did use a small syringe (3-4 oz.) to try to draw it down, but it almost feels like there is never any fluid getting into the master. On the front or rear. And this is how I bled my GSXR brakes and it worked fine and it had new lines as well.

I Did rebuild the aft master, but I just disassembled and cleaned the front. They both worked when I took them apart, although the rears worked much better than the front. But I can't get either to draw fluid.

Also the bolts holding stuff together were all round. no flat spots??

Is the small syringe not enough? Should I try a vacuum blender?

Thanks guys.

[EdgeGrip]

If you have a fairly tight fitting bleed hose (at the nipple), and of around 3 feet long, i got the front brake lines (3 in my case) primed by creating a vacume at the far end of the hose,.....with my mouth.

Now, i did make sure to clean the end i was mouthing, and my hose was clear so i wouldn't get a nasty surprise.

But sucking on it much like a straw, only harder, while pumping the front brake lever got the fluid down quickly. Once you have just a few inches showing in the clear hose, you can stop the vacume and working the lever will continue the process. Keep your resevoir fairly full,....don't want air to get back in.

Again, please be sure to clean the hose first,...AND don't continue once fluid is showng a few inches in your THREE FOOT CLEAR HOSE. Use common sense, as i assume NO responsibility for carelessness.

BTW, i found my rear brake single hose was a bit easier,.....can probably skip the sucking there.

.........and yes,.....i did syphon gas occassionally when i was younger,.....and THAT is way less fun without a master cylinder helping it along! (or the syringe type today)




Hehe,....just call me mityJoevac!

I'll try this. I have 1/4" clear tube, and plenty of it. Haha.