Need help with brakes

[olhogrider]

I rebuilt the master cylinder, replaced the brake lines, cleaned up the calipers (pulled pistons and cleanedpassages), bled the system until there is no air. Still no pressure build up at lever and no grab on calipers... What should I look for? What am I missing? Please HELP!!

[Evert]

Hi!

Did you put a hose on the bleeder and submerged it in brakefluid?
Squeeze the brakelever with the bleeder open, then shut the bleeder and let go of the brake lever, repeat until bubbles are gone.
This takes a while, keep brake fluid in the reservoir, to prevent air from entering the system.Have patience

[dragxs11]

You bled the air out the bottom? I've learned a little about this. Just put steel braided lines on recently and had my front master cyl. rebuilt. You may already know the the air keeps wanting to climb up to the master cyl. My mechanic helped me out here. Compress the cyl. slow, then let it snap back. This helps the air get up and out of the line. I didn't need to bleed any fluid out the bottom. It takes 20-30 pumps. If everything it working right, that should work.
Matt

[rockyr74]

I have one of those hand pumps, mi-tee-vac or something like it and it works very well in these cases. Rather than pushing brake fluid back and forth, it sucks it through.

[cybergost1]

same problem

i feel like a idiot when i had the same problem i messed with for a couple of days on the rear brakes.
i took my calipers apart too to clean them they had rust in the lines and in the cailpers too. when i put then back together I put the rubber o-ring upside down. it would never build preasure, but once i filped it the stiffened up with no problem.

But

The brakes still feel spungy and i have done everything every one else suggested. just figured its the way they are.

[ratbyk]

Same problem

When I put a kit in the rear M/C I also had trouble bleeding and getting a hard peddle.
Discovered that if I removed the cylinder from the frame but left the lines etc. hooked up, tilted the cylinder slightly from it's normal vertical position that I was able to bleed (BY HAND ON THE PUSH ROD) the last of the air out of the system.
Also I adjusted the push rod a little deeper into the cylinder to remove most of the free play in the stroke. I have a very hard and comforting peddle now with a very firm feel.
I have gone almost 2500 km since without any further work on the brakes.
Hope this helps.
Ken/Sooke
78E Ratbyk

[cybergost1]

thanks

thanks will try i feel i have put about a gallon of fuild though it but anything is worth a try.

I bought this bike about a month ago and have been playing with with it a 79 xs11f. thanks to this site i have been makeing lots of head way with it.

[Ken Talbot]

Cyberghost - one thing to remember is that as long as you have the original rubber lines on your bike, you will have spongy brakes to a certain degree. Even when they are fully and properly rebuilt and bled, the lines simply expand under pressure and you lose some braking effect. Braided stainless lines are not cheap, but they do make a world of difference.

[Pat Kelly]

I had the same problem bleeding my brakes too. My solution is a little dangerous so I only did one end at a time.
After bleeding and bleeding to no avail, I just rode the bike anyway knowing full well that I had no front brake to rely on. The vibration and road bumps worked the air back up to the master cylinder and after a day or two the lever became rock solid. At that time my problem reversed itself and the front would slowly beging to lock-up on me. That's when I learned about the spooge hole (thank you list).
All this was frustrating to me because I was a front-end and brake (cage) mechanic for many years and this was the 1st vehicle I couldn't bleed. Wifes XS750F was the same way.

[cybergost1]

tried as ratbyk suggested and they did get rock hard but the caliper was so tight against the rotor i bleed the brakes to get it to back off. now they are just like they where spungy. My spunge hole was clean so i am going to take it apart again and check to to see if the hole is dirty again.

oh i replaced the lines on the back with new lines not braided lines but new lines. going to check out the braided lines anyways.

oh and pat i did the same thing on my front brake just rode on the back rodes around here and the next day they where great. difference between night and day. just wish the rear would do the same lol

[ratbyk]

Drag in rear caliper

Before you take the master cylinder apart I suggest that you;
1. Rebleed the cylinder off the bike by hand again.
2. Back off the push rod a bit. You have it adjusted too far in and when you release the brake peddle the piston & rubber cups in side are not returning enough for them to clear the compensating port in the cylinder bore. This is allowing the pressure to build up but not escape after releasing the pedal.
Ken/Ratbyk
78E Ratbyk

[cybergost1]

duh i guess i got to excited that i got a hard pedal that i didnt think to check to simple stuff. because it was hard to get back on but i wasnt thinking

devil in the details thanks will try again

[cybergost1]

just went out and did it again and now it is fixed.

thanks
ratbyk

[ratbyk]

Your Welcome

Ride on with a smile AND brakes.
Ken/Sooke
78E Ratbyk

[olhogrider]

Got tired of trying to fix the master cyl and bought a "new" used one. Looks different, but works great!