Kawasaki Motorcycle Forums banner

1 - 13 of 13 Posts

·
Registered
Joined
·
62 Posts
Discussion Starter #1
So I go to replace the fluid in my 79 kz1000 st. Blow out all the lines clean everything up reall good. Put new pads on the rotors. Use a toothpick to clean the two little holes in the resevoir. Even with a vacum pump i can not get brake fluid to come out of the resevoir. Crack the lines by it thinking maybe a vapor lock. Nope. When i operate the handle it pumps air out the bleeder but no fluid. Pump the brake close the bleeder and then release it open the bleeder and it seems like theres back pressure. Same sound as when i pump it. Been beating me up for two days know. HELP.
 

·
itching to ride
Joined
·
2,233 Posts
Did you clean out the master cylinder and or rebuild it? Sounds like the pump in there is worn or needs cleaning. My back was like that and all it needed was a good cleaning. The front was too far gone so I replaced it.
 

·
Machinist For Sale/Rent
Joined
·
1,234 Posts
When i operate the handle it pumps air out the bleeder but no fluid. Pump the brake close the bleeder and then release it open the bleeder and it seems like theres back pressure. Same sound as when i pump it. Been beating me up for two days know. HELP.
If you are doing exactly what you describe above then my friend you are doing it wrong.
You are pressure bleeding by using the master cylinder to pump up pressure, right?
If this be the case then you need to leave the bleeder screw closed. Pump the handle a few times and hold it squeezed or depressed, open the bleeder screw-just a little and allow the pressure to escape. Close the bleeder valve and repeat the pumping.
Another way to do this, especially if your arms aren't long enough to hold the lever and reach the bleeder is to buy the "speed bleeders" that are sold. With them you crack open the bleeder and pump, there is a check valve in them to prevent drawing air back into the system as you are doing now.
 

·
Registered
Joined
·
251 Posts
At the very least, assuming the master cylinder is clean, the process of bleeding (or the way you are describing it) is the reverse of what you need to do.

Close the bleeder (which should have a clear tube attached to it that goes down to a jar of clean fluid on the floor). Pump up the lever and hold it hard. You may not have much lever until much of the air is out. While holding it, release the bleeder while still squeezing, air and fluid should rush out (possibly just air at first) through the hose and you will feel the lever collapsing to the bars. Before the lever gets squeezed almost all the way closed while squeezing, tighten the bleeder (if you hold the lever all the way closed and then tighten the bleeder, air can get back in). Repeat this process until you get just fluid, then close the bleeder for good. That usually does it.

To get past this hassel, I made a pressure bleeder from a garden sprayer that works great for maybe $10. Search on Google and you'll find instructions.
 

·
Registered
Joined
·
62 Posts
Discussion Starter #8
Thank=You everyone who gave me input. Yes i was doing it wrong. After following some advice here i got it to bleed. I am not happy with the way the handle works now though. I may have dislodged so much junk that my handle takes a while to come all the way back out. I will be totally dismantling it and either cleaning or replacing the internal parts. Somebody mentioned a cir-clip on the lever side? Is that under the rubber boot that covers the stem?
 

·
Registered
Joined
·
62 Posts
Discussion Starter #9
did you pull the master apart ? if not then it may be all gummed up inside and not able to pass fluid to the line/calipers...
pull the lever off and youll see a cir-clip that you can pull out and then all the gus will come out of the master. either clean it all or replace it all.....

How to Clean a Motorcycle Master Cylinder's Internals: How to Repair Motorcycle Brakes | eHow.com
Nice little video on cleaning your master cylinder. After watching it I will definetly be taking it apart tomorrow after I'm done at work!!!
 

·
AZ's Official Mechanic
Joined
·
5,201 Posts
Somebody mentioned a cir-clip on the lever side? Is that under the rubber boot that covers the stem?
yes its under the little rubber cover... it may not come out in one piece . it has a small steel ring that holds it in place and it likes to corrode in place..maybe use some PBBLASTER down around it before pulling it out....
the vid i linked to doesnt show you disassembly which is the biggest part.. cleaning/lubing/putting back together is the easy part.. heres a whole page of stuff to look at/read...

How to Clean a Motorcycle Master Cylinder - Google Search
 

·
GHOSTRIDER
Joined
·
3,361 Posts
The 80 KZ1000 has a nylon sleeve that locks the piston into the bore/cylinder. The pistons are often stuck in the master cylinder. A 1/4" steel rod or phillips screw driver can be used through the banjo bolt opening to push the piston out of the master cylinder. There are two slots, top and bottom, at the piston bore opening that are the locks for the nylon sleeve. Depress the locks with a small screw driver to release the nylon sleeve.
 

·
Registered
Joined
·
62 Posts
Discussion Starter #12
You were right Zoro I had the nylon sleeve. After cleaning everything up real and reassembling the piston would not come back out completely. After cleaning everything a second and a third time I finally realized I had the spring backwards. It rests against the retainer for the last ruuber ring. I felt like a complete idiot. Another lesson to look close before you take something apart. Drove it the last two days and every day it seems to run better and better. Starts like right now and idles (purr-Purr). Thank=you all again for your words of wisdom. Happy riding.
 

·
Machinist For Sale/Rent
Joined
·
1,234 Posts
You were right Zoro I had the nylon sleeve. After cleaning everything up real and reassembling the piston would not come back out completely. After cleaning everything a second and a third time I finally realized I had the spring backwards. It rests against the retainer for the last ruuber ring. I felt like a complete idiot. Another lesson to look close before you take something apart. Drove it the last two days and every day it seems to run better and better. Starts like right now and idles (purr-Purr). Thank=you all again for your words of wisdom. Happy riding.
Don't it feel great to be able to accomplish these jobs yourself? I cannot imagine some of the guys we read about who take their bikes into a dealer for the simplest thing.
You have overcome quite a hurdle, most people who are accomplished at any engine repair or trans repairs would never tackle a master cylinder with the same determination you have, they simply would have wasted big dollars at the dealer.

Kudos man, you deserve it.
 
1 - 13 of 13 Posts
Top