The front disc brakes on my atv have been locking up on occassion with the squeeze lever becoming too hard to pull. I read in the manual that fluid should be changed periodically. Since mine is very old, I decided to change the fluid this morning. Reading the manual, it says loosen the bleeder valve and pump the hand lever until the old fluid is gone. Then, put new fluid in the resevior and do the following:

With the bleed valve closed, attach hose to bleed valve nipple. Place other end of hose in small jar filled with brake fluid. Squeeze hand lever and hold while loosening bleed valve nut. Air bubbles come out during this process. Tighten bleed valve nut, release hand lever and repeat process until all air is bleed.

I did both left and right separately until the air was gone but never gained any pressure in the hand lever and the brakes are barely working. I tried pumping the hand lever and this didn't help.

What am i doing wrong? Any ideas as to how I can get my brakes working? I know this process isn't that hard but i am obviously doing something wrong.

thank you.
dave

 

The first thing I would do is take a felt-tip marker and write through the statement in your owner's manual that says to periodically replace the brake fluid. I would equate that to changing the air in your tires. Your brake system components will probably wear out and require a disassembly of the brake system before the fluid will ever need replacing. I really believe your original problem as the result of a mechanical problem, most probably with the brake wheel cylinders.

In any case, I would say your problem is the result of either remaining air and/or a leak in the system. Remember that air left anywhere in the system will compress where brake fluid will not. Are you sure that you are re-tightening the bleed valve before you release the brake lever? Also, are you pumping the lever prior to opening the bleed valve and then holding pressure on it as you open the bleed valve? Most people view this as two person job with one pumping and holding the lever as the other controls the bleed valve.

In other words,

1. Pump the lever several time and then hold it down.

2. Open the bleed valve to remove any air. (Feel free to poor fluid back from your jar back into the master cylinder as you repeat these steps.)

3. With lever still held down tightly, close the bleed valve.

4. Repeat steps 1-3 until no air appears in the bleed line are several attempts. Again, feel free to place bled fluid back into the master cylinder if necessary to keep it full.

I suspect that if you follow the correct procedure and bleed the system repeatedly so several minutes, you should see improvement. However, once you get the hydraulics back in order, you will probably still have the mechanical problem with your brake cylinders.

Good luck!

 

I disagee with you (and so do most repair manuals). The brake fluid will slowly absorb moisture, and degrade the performance of the fluid. Best way to change the fluid is to use one of those hand pumps (or vacuum pumps) that can draw the fluid through the lines from the brake caliper, while you add new, fresh fluid at the reservoir. I have done this on all my older vehicles, and it is relatively simple to do.

 

I agree with RUBICONBOB. It is true that brake fluid draws moisture. ALWAYS use fresh brake fluid, never re-use fluid that has gone through the system. Brake fluid is relatively inexpensive compared to all of the components in your braking system. A MIGHTYVAC (vac. pump) is the best way I have found to bleed motorcycle/atv systems, no opening and shutting the bleeder screw and no mess. Just make sure to keep the master full of fluid.
Exer

 

I'm not trying to insult you or anything but could the problem be that you aren't closing the bleeder screw/valve before you let off the lever?
You always HAVE to close the valve, then let go of the lever. If you let go of the lever first it will allow air back into the system.
1. Pump the lever a few times to start. Make sure the master cylinder is full of fluid.
2. While firmly holding the brake lever back open the bleeder valve for a few second, then close it.
3. Let go of the brake lever and pump it a few more times.
Now just keep repeating that over and over and you should start to get brake pressure back.
Mike

 

One thing i wanted to add.....
If you (anyone else)are going to try changing the fluid don't open the bleeders and let all of the fluid out.
Rather than doing that, just keep bleeding the brakes (by doing the above) and keep filling the master cylinder with new brake fluid. Just keep doing that until the fluid looks nice and clean.
Doing it this way will lessen the chance that you will lose all brake pressure. Once you lose all brake pressure it's hard to get it back.
Like one of the other guys said, it's alot easier to bleed them with one of those handheld brake vacs.
Mike

 

thanks for the advice. I will need to make certain i am fully closing the bleeder valve and secondly, pump the lever.

 

Well I agree with "Spring", there's no need to ever change the brake fluid. It's a closed system and will not absorb moisture. I would however never reuse old brake fluid unless it was a "have to" situation. I bled the rear brakes on my Warrior last week for the first time in 13 years, no moisture in there, it was just a tad darker than the new brake fluid. See-Ya gotta go and change that old air in my tires. LOL.

 

Better yet guys, make sure you purchase brake fluid made by Honda and change it often. I mean the brake system on an ATV is not like those you'll find on the average automobile. And while you're at it, write them a letter and ask that they start producing their own gasoline.

 

the quick + easy brake bleeding method.. take a piece of clear hose, put it over the bleed screw, and open it slightly. take the other end and put it in a CLEAN jar with enough brake fluid in it to cover the bottom of the hose. Gently pump the brake (making sure to keep the resevoir topped off) until you don't see any bubbles in the hose, and shut the bleeder. It's a bit more work than the vacumn setups, but cheaper

The fluid resevoirs are vented, don't count on the rubber gasket keeping everything out either. In a perfect world, maybe... Don't take my word for it, go to a parts store and get one of the test strips, dip it in your brake fluid.. you'll be suprised how much water is in it

my .02

Leo