Hello!

New to the forum, been lurking for a bit...

I have a 2002 Warrior that after sitting for a month or so the rear caliper tightens up on the rotor, I cant even spin the rear wheels.

I have to remove the caliper, push the piston back in and then its good for a bit.

Why would the caliper clamp onto the rotor with out even applying the rear brakes?

 

Is the parking brake still on it?

 

No pulled it off a couple of months ago.

Still confused that it tightens up on the rotor all by itself..??

 

That is weird. Is it possible there is a lot of water in the brake fluid and it freezes in the winter, causing the piston to be pushed out? Or does it do it in the summer, too? You should change your fluid every 2 years or so, maybe it wouldn't hurt to go ahead and change it.

You can rebuild the caliper for a few dollars, there's 2 seals in the caliper, 1 on the piston and 1 on the shaft. Just push the piston all the way out, replace the seals, and push the piston back in, then bleed the brakes.

 

Last winter was my first winter with this quad. I did try to change the fluid when it happened during the winter, but it still did it again. Its been in the high 70's to 80's here in Connecticut for the last month, so temperature doesnt seem to be a factor.

Personally, I've been swinging wrenches for a long time and I've never seen anything like this. I took the caliper off last night and brought it to work with me today to take apart. Maybe I'll find something, but I'm not so optimistic. The only thing is the fluid for some reason is expanding. The caliper basically locks up the rear wheels like someone is stepping on the brake. That's a decent amount of pressure....

 

Yeah I don't think anything could push the piston out but pressure coming from somewhere. The only things I could think of would be the brake fluid expanding for some reason or the master cylinder is holding pressure and releasing it slowly? I think the master cylinders are easy to rebuild, too. Either that or you need a ghost hunter.

 

For there to be pressure in the system the master cylinder piston must not be returning to the open position. The piston must come back far enough to open the drilling between the cylinder and reservoir or an increase in temperature will cause the fluid to expand and lock the caliper on.

 

Well pulled the rear caliper apart and found nothing out of place, guess it's on to the master, I'll let you guys know.

Now I got another problem with it running...?