any tips for bleeding brakes?

I just painted my calipers and put on new front pads. '80 Kz 1000 G1, dual front brakes. I'm following the instructions on bleeding brake lines in the manual and not getting any where. I'm just running fluid through the lines and refilling the master. Not taking it down too far, but every time I check, I need to add some.

There has to be either air somewhere in the line, or a leak somewhere. i don't think that theres a leak because no fluid running out.

any hints or tips would be appreciated.

thanks

Dale

I knew that this was a question answered just recently. I searched through the items and found the tip about zip tieing off the brake handle. Going to try it now.

Also, I had the whole master cylinder apart and had a heck of a time getting it back together. ended up using the shop vac to create negative pressure inside the cylinder to allow me to get the rubber gaskets to fit without cutting them up.

Rear brakes bleed easily in under 2 minutes.
It is the front brakes that cause all the trouble.

I have a Mityvac brake bleeder (under $30) which Sucks from the brake bleeder. I rate it's usefulness at a 7 (out of 10) It takes about 10 minutes and 1 can of brake fluid.

My favorite tool is a small pump oiling can - the kind with a squeeze handle. Under $3 at the hardware store. I connect it to the bleeder nipple with a hose and pump back up to the master cylinder. I rate it at a 8.5 out of 10.
It takes about 6 minutes and a 1/2 can of fluid.

Useful tricks:

If bleeding without above tools put a hose on bleeder running to a jar on ground so that the end of hose is in brake fluid. That keeps you from sucking air back in when you use the pump and bleed method.

Buy the good brake bleeder nipples with a rubber seal around the threads. eBay. That keeps you from sucking air back in when you use the pump and bleed method.

If using one of my favored bleeding tools put a hose clamp around the handlebar and brake lever. With the master cylinder cover removed slowly tighten the clamp until you see a few very small bubbles rise in the reservoir. You will only be pulling on the lever a small fraction of an inch (maybe 1/4" ) The purpose of this is to put the port of the m/cyl pushrod directly over the return port in the m/cyl. This allows more air to escape from the system.

Several times during the bleeding process flex and tap the front brake lines to encourage bubbles to rise to the master cylinder. Also turn the handlebars side to side while tapping, for the same reason of encouraging bubbles to rise.

Cover the gas tank and engine with a plastic garbage bag to protect the paint.

Take a look here...


Brake-Bleeding Post

FloridaBiker wrote:

Rear brakes bleed easily in under 2 minutes.
It is the front brakes that cause all the trouble.

I have a Mityvac brake bleeder (under $30) which Sucks from the brake bleeder. I rate it's usefulness at a 7 (out of 10) It takes about 10 minutes and 1 can of brake fluid.

My favorite tool is a small pump oiling can - the kind with a squeeze handle. Under $3 at the hardware store. I connect it to the bleeder nipple with a hose and pump back up to the master cylinder. I rate it at a 8.5 out of 10.
It takes about 6 minutes and a 1/2 can of fluid.

Useful tricks:

If bleeding without above tools put a hose on bleeder running to a jar on ground so that the end of hose is in brake fluid. That keeps you from sucking air back in when you use the pump and bleed method.

Buy the good brake bleeder nipples with a rubber seal around the threads. eBay. That keeps you from sucking air back in when you use the pump and bleed method.

If using one of my favored bleeding tools put a hose clamp around the handlebar and brake lever. With the master cylinder cover removed slowly tighten the clamp until you see a few very small bubbles rise in the reservoir. You will only be pulling on the lever a small fraction of an inch (maybe 1/4" ) The purpose of this is to put the port of the m/cyl pushrod directly over the return port in the m/cyl. This allows more air to escape from the system.

Several times during the bleeding process flex and tap the front brake lines to encourage bubbles to rise to the master cylinder. Also turn the handlebars side to side while tapping, for the same reason of encouraging bubbles to rise.

Cover the gas tank and engine with a plastic garbage bag to protect the paint.

If you don't have fancy tools, you can avoid sucking air in by getting an assistant who will snug off the bleed fitting AS FLUID IS STILL COMING OUT FROM YOU PUMPING THE HANDLE.

Just keep topping off the reservoir and NEVER LET THE LEVEL GET LOW because then you will pump air back into the line and you are screwed again.

IMPORTANT: cover the open reservoir with a rag or something to keep it from spitting fluid as you pump.

Thanks all for the tips. I tried the oil can method and it got some of the air out. Then I still had problems, so my trusty helper (my wife) suggested that there might be some air trapped in the splitter.

So, since I always listen to my wife (:laugh: ) I took the splitter off and tipped it around and tapped on it a little, sure enough, more air bubbles.

then I decided to remove the calipers and shake them up a little bit, more air.

then I decided to go back to the splitter again.

this back and forth went for quite a while and I could start to see some progress.

I kept working at it and taking brakes because my wife needed some work done too.

After supper I worked at it some more and then I could see that the pads were in contact with the rotors, so I lifted the front on on my stand, spun the front tire, and pulled the brake and it stopped.

I finished putting it back together and rode it up and down my street a little. It stops the bike, but there is still some air somewhere because it was pretty mushy. I'll have to keep working on it but I think I am on the right track.

the only other question I have is this:

when I was putting the piston back into the master cylinder, I think I might have nicked up the 2nd gasket going in. Would this draw air into the system? I thought it might, but then I told myself that this this was true, then fluid should come out too, right?

I'm scared if this is the case because there is probably no changing this gasket, meaning I would have to buy a new one.

you went through all the PIA stuff to bleed the brakes,, I think you may stll have air in the master cyl,
I would just about have a ass whipping than have to bleed the front brakes.

I suggest reverse bleeding. Compress the caliper piston(s) and force fluid back up into the master cylinder. While doing this, also lightly tap on the caliper and tap on the junction block (if you have one). Use the brake lever to pump the fluid back into the caliper(s). Repeat this several times. Be careful not to push too much fluid into the master cylinder and overflow it. Also, be careful not to pump too much fluid into the caliper(s) and push the piston(s) completely out. You would then have to start over (after cleaning up the resulting mess). I have a pressure bleeder which I thought would work better than any other method I've read about here. Not so. It still can't push all the bubbles down into the caliper(s). Some of the bubbles can only be removed by pushing them upward. After bleeding my system with my pressure bleeder, using the above method I still got more air out.

BSKZ650 wrote:

you went through all the PIA stuff to bleed the brakes,, I think you may stll have air in the master cyl,
I would just about have a ass whipping than have to bleed the front brakes.

After going through this effort, I am in agreement with you.

what really ticks me off is that I painted my calipers and they looked really good. However, with all the bleeding and etc. I messed up the new paint.

Plus the frustration of not seeing any progress for a long time. I am really close now, but still a ways to go.

Thanks all for the kind words and encouragement. I'm sure I'll get there. I just have to be more patient.:S

I use DOT 5 when I redo the brakes,, dosent eat paint, and dosent attract water,
Some will dissagree, but I have seen brakes with it in there for years and the fluid is just as clean as it was when new