Questionhello again i have a question i have a 1987 kawi ninja zx750r just got it back had it in shop to do rear disk brakes but got back and they dont work calipers move little but not enough to stop can u tell me why this can happen or could it just need fluid. p.s i am told the are hydrolic brakes if thats correct.
AnswerHi Joe.
First thing I'll tell you is to find another shop to do your work. I guess they don't check to see if any of the safety items work before they return the machine.
Check the brake fluid. It should be at the full mark.
Then bleed the brakes. BTW, they are hydraulic brakes. That means it uses fluid to actuate the system. The same proceedure works for hydraulic clutches as well.
Here's the bleeding proceedure:
1) Put the bike on the centerstand and remove the cover (cap) of the master cylinder.
2) Fill the clean container with some brake fluid, but don't use it all. Attach the bleeder hose to the bleeder valve (it's a nub with a hexagonal base to it at the top of the brake itself). Put the other end into the container that you just put brake fluid in. Open the bleeder screw a bit while pressing down on the brake pedal/lever and close it before you let up on the pedal/lever. You will probably see bubbles in the line. Be sure to refill the master cylinder before it get's too low and repeat this process until you no longer get bubbles in the bleeder line.
3) Tighten and close everything up when done.
4) Ride away and have fun.
Some bikes have an additional problem with both the clutch and front brakes, including my own. The problem stems from the configuration of the master cylinder, which is that the connection to the hydraulic line at the master cylinder creates a pocket that air bubbles like to hide in (this is
called a reverse trap) and the method for bleeding that section is a little tricky if you've never done this before.
Here's the proceedure;
1) Bleed the clutch/brake line like normal.
2) Put a wrench on the banjo fitting and squeeze the lever.
3) (NOTE: Use a box end wrench for this) While holding the clutch/brake lever in, crack loose the fitting and reclose it quickly. Have a rag over the fitting connection that you are working on because it will spit at you as pressure expells the air and a little fluid.
IMPORTANT NOTE: Do not release pressure on the lever till the fitting is tightened back up or you will suck air back into the line.
4) Test the clutch/brake again. If done correctly, you will have pressure near the beginning of the lever movement rather than at the end.
5) repeat as needed, but should not need more than 2-3 times.
Good luck.
FALCON
