I noticed a few rides ago that the foot brake on my 00 SP500 was useless. It depressed as though it wasn't connected to anything, and it had no effect whatsoever on the actual brakes. I never use it anyways, so I figured I'd give it a look some other time. Then the other day I had almost no brakes when I used the hand brake while unloading my atv after a long drive. I also seem to remember the hand brake kind of fading a little during my ride, but I can't remember for sure.
I just went out right now to give it a look-see, expecting to see a broken cable on the foot brake, or maybe some worn brake pads. I tested the hand brake, and it seems to be working just fine right now. There is no cable TO break on the foot pedal, just a lever that pushes a rod into a cylinder, and I can see on the rod as it comes out of the cylinder that there is what I assume to be brake or hydraulic fluid on the rod. The brake fluid in the handlebar resevoir is about halfway between "Max" and "min".
Now I would assume that I simply need to add more brake fluid, which would in turn add more fluid in the lines, eliminate my brake fade, and render the foot pedal useful again. But since I'm no mechanic, and since I don't want to find out I'm wrong by crashing my atv into something, I thought I'd ask someone who knows what they are doing.
Thanks in advance!

Scott Tafoya

 

NEVER NEVER NEVER NEVER NEVER NEVER NEVER NEVER NEVER NEVER NEVER NEVER NEVER NEVER NEVER NEVER
Add brake fluid to the brake system, unless there is an obvious leak. To see if you need fluid, take a screw drive and gently pry the pads away from the rotors to the position they would be in if they were the new thickness. Then check your level.

The fluid level is actually an indicator of the wear on the brake pads. When it is on the "MIN" your pads are at or beyond their minimum thickness. Or should at least be looked at. If you added fluid now, it would bring the level back up. But what happens to that fluid when you install new pads???? You compress the calipers so the new pads will fit and the fluid has to go somewhere. It will blow out a seal somewhere. Whichever seal is weakest in the system.

Brake fade is usually a result of the type and condition of the pads, and the overall design of the braking system. Brake lines are cheaper, so they expand more when hot, .... things like that.

Good luck,
Gary

 

Acro,

There is another brake fluid resevoir under the seat for the foot brake circuit. Check the fluid there and check for leaks.

The hand lever (and resevoir) press one of two pistons in the rear caliper. This piston pushes the pad against the rotor which in turn centers the caliper on the rotor and applies pressure to the other pad. There is a second piston behind the other pad. This piston is controlled by the foot pedal (and its resevoir under the seat).

Basically one caliper with two independently controlled pistons. They are independent BUT, they rely on the other piston and pad to counter the pressure applied.

As Brasspad indicates the pads must be good. Check the pads, they wear faster than you think.

If you change the pads you will push both pistons back to get the new pads in. When it is all reassembled you have to depress both the hand lever AND the foot lever several times to push both pistons back out where they can do some good.

Sounds like you need new pads or there is a leak in one or the other of the brake circuits.

DJ