Bleeding the Front Brake


12 replies to this topic
  • 913YZ426MXer

Posted October 03, 2005 - 08:32 AM

#1

Machine: '01 YZ426F
Problem (initial): mushy front brake (discolored brake fluid)
Solution: Bleed system with new DOT4 and make adjustments where needed.

Where I am now.................After following several recommendations concerning the procedures for bleeding the brake system I have no front brake. NONE! Beyond mushy, more like non-existent. Using clear 1/4" tubing, making the loop and running the excess to a bottle I started the bleeding process. Old fluid out new fluid in. Everything looking good until it came time to close the bleed valve. Once closed ( and lever depressed), I could not get pressure to build up to have a recognizable front brake.

HELP IS NEEDED..........THX!

Cheers!

  • BC61

Posted October 03, 2005 - 08:43 AM

#2

was the bleed valve open the entire time you pumped new fluid through the system?

  • walent215

Posted October 03, 2005 - 08:45 AM

#3

make sure you are closing the bleeder after each time you pull the lever in.it helps to have two people so that you can pull the lever in and hold it while the other person works the bleeder.keep the lever pulled in until the other person has copened and then closed the bleeder.then repeat until all the old fluid is pumped out and new fluid is in reservoir.

  • grayracer513

Posted October 03, 2005 - 09:03 AM

#4

There are two ways to beat this. First, the problem is that you have a bubble in the line, and there is so little fluid moving through the system that it either is simply flowing "around" the bubble, or just can't move it far enough to get it to the bottom; it keeps moving back up between strokes.

So, you can either bottom bleed it by using a CLEAN squeezable container to force fluid into the bleeder and up through the line to the master cylinder (have someone hold a pan under the open master cylinder, this can be messy otherwise), OR...

unbolt the caliper and hang it at a point higher than the master cylinder and bleed it in the normal fashion. Either of these tricks will get the air to go where you want it to.

  • 913YZ426MXer

Posted October 03, 2005 - 09:38 AM

#5

The bleed valve was NOT opened and then closed with the lever depressed. We were simply squeezing (Pumping) with the valve (1/4 - 1/2 open). I will try your suggestions tonight and should have different results to report.

Just so I understand this properly, I should depress the brake lever (full) with the valve open, then close the valve with the lever in the same position and then release it. Provided that I believe there to be no air in the line.

Guys, thanks for your input. Stay tuned. There might be more questions.

Cheers.

  • walent215

Posted October 03, 2005 - 09:58 AM

#6

The bleed valve was NOT opened and then closed with the lever depressed. We were simply squeezing (Pumping) with the valve (1/4 - 1/2 open). I will try your suggestions tonight and should have different results to report.

Just so I understand this properly, I should depress the brake lever (full) with the valve open, then close the valve with the lever in the same position and then release it. Provided that I believe there to be no air in the line.

Guys, thanks for your input. Stay tuned. There might be more questions.

Cheers.

depress the lever with the valve closed and hold it while the othe rperson opens the valve .keep tension on the lever bc once the valve is opened the lever will move in toward the grip and if you dont have tension on the lever it will suck air back in the system.the person working the valve will need to open and close the valve rather quickly-just long enough to allow a little fluid to escape and then back closed-then repeat this until you have a good feel at the lever.

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  • 913YZ426MXer

Posted October 03, 2005 - 11:02 AM

#7

depress the lever with the valve closed and hold it while the othe rperson opens the valve .keep tension on the lever bc once the valve is opened the lever will move in toward the grip and if you dont have tension on the lever it will suck air back in the system.the person working the valve will need to open and close the valve rather quickly-just long enough to allow a little fluid to escape and then back closed-then repeat this until you have a good feel at the lever.


:banghead: Now this sounds better than the rest of what I was working with. I will try it tonight. Thanks again.

Cheers.

  • RCannon

Posted October 03, 2005 - 05:14 PM

#8

After you bleed the brakes, use tape or a zip tye to hold the lever in overnight. This always improves the feel. I think it lets the little bubbles work the way to the top.

  • Matt96xr6

Posted October 03, 2005 - 06:57 PM

#9

IF you have air in the lines, easiest way to do this is to open the bleeder and have a clear hose run up and over the tire to a catch can. Then pump the brake lever from about 1/2 to full never letting it fully return about a dozen times. If you have air in the lines, you will get it out this way. Be sure the reservior is filled before starting this.

  • crfmatt

Posted March 25, 2006 - 02:16 PM

#10

I am having a problem similar to this..I was installing seal savers today and once i put everything back on I have no braking now. With the caliper off I can pull the lever a million times and get the pucks to extend however when i put the caliper back on the rotor I cant get any brake action. And I am sorry but I am not sure the whole bleeding process???

  • 426_Texan

Posted March 25, 2006 - 05:11 PM

#11

After you bleed the brakes, use tape or a zip tye to hold the lever in overnight. This always improves the feel. I think it lets the little bubbles work the way to the top.


^^^ Do what he said, works great ^^^

I would add that when I did this, I pumped mine a few times first, then zip-ty'd it :thumbsup:

  • crfmatt

Posted March 25, 2006 - 05:47 PM

#12

My prob,em is I dont even know what you do to "bleed" the brakes? :thumbsup: :thumbsup:

  • Numskull

Posted March 25, 2006 - 05:50 PM

#13

Bleeding your brakes refers to getting all of the air out. Your brake lines should be full of hydraulic fluid(brake fluid) with no air. Air compresses where fluid does not.
You should be able to pump the lever and compress the air to give you pressure. Once you have pumped the lever to compress the air, hold the lever in. Now break open the bleeder to release the compressed air. Tighten the bleeder down, now you can release the lever and pump it again until the air compresses, making sure you keep your reservoir full. Repeat this procedure until you have a firm lever with no compression.

In the event that does not work, do what gray racer said :thumbsup:





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