Jump to content
Sign in to follow this  

brakes locking up????

Recommended Posts

ok i am no dummy when it comes to motorcycles, but my buddy brings me his 2000 kawi kl250. he said the front brakes locked up oin him. so i change the fluid and bleed the brakes. take it around the block and sure enough the front bracks got really hard and would not release. i thought it was the master cylinder bleed hole by the cap. so i cleaned it really well, and it seemed to fix the problem. but i ordered a new one because he plans on riding it to work so i dont need him crashing. so im waiting on parts and my other buddy dropps off his klr250.its only 2 years old. i change the oil for him and decide to ride it around town just to make sure it is running good. and now this ****ing bike did the same thing. i took the cap off and nothing. locked up!! so i had to open the bleeder on the caliper to relieve the pressure. i am stummped to the problem. the only other thing i can think of is that the fluid is crap and getting super hot, but the previous owner of the new one rode it to work which is about 8 miles each way. i only rode it 3 miles. really weird.

Share this post


Link to post
Share on other sites

There is a relief port in the bottom of the master cylinder that allows the fluid to return to the M-cylinder. If it gets clogged the brake won't release.

My KDX manual (yeah I know, different. But all m-cylinders work pretty much the same) lists it as a prime cause for what your describing and recomends blowing it clear with compressed air.

Worth a look.

Share this post


Link to post
Share on other sites

As you found on the first one, brakes self applying due to heat is caused by the bleed hole in the master bore either being plugged or the piston not traveling back far enough to uncover it due to dirt or corrosion or misadjustment. If it is not blocked, no amount of boiling will lock up the brakes.

Edit: Reread your post. The bleed hole is not in or near the cap it is in the cylinder itself. When you first start to apply the brake you can see a little fluid coming up from it into the resevoir.

Share this post


Link to post
Share on other sites

Ok so pull the dust cover off and lube it and check for corrosion. And pull the cap and make sure the hole on thevpiston isn't clogged? The tiny hole where the cap meets the master there is a tiny hole. I was told if this is clogged it will also cause this. Thanks guys.

Share this post


Link to post
Share on other sites

If the plunger is not returning far enough the bleed off port in the master cyl will not get uncovered and the brakes will lock up. I had the screw that depresses the plunger, screwed in too far and that led to the brakes catching fire:busted: :worthy:

Share this post


Link to post
Share on other sites

Have you ever thought of taking up the piano?

No offense, but everyone loves pianists, and they are so rare today.

  • Like 1

Share this post


Link to post
Share on other sites
Ok so pull the dust cover off and lube it and check for corrosion. And pull the cap and make sure the hole on thevpiston isn't clogged? The tiny hole where the cap meets the master there is a tiny hole. I was told if this is clogged it will also cause this. Thanks guys.

I would't have thought the cap itself would hold enough pressure to lock up the brakes but if that's what you found on the first one I'll buy it. Same principle.

Share this post


Link to post
Share on other sites

Not familiar with the KDX, but if it has a rubber brake hose, the inner liner can collapse and act a like a check valve. If it has a hard plastic hose, it's not likely collapsed.

If you open the bleeder and the front wheel releases, then it's either the brake hose or master cylinder. If you open the bleeder and the wheel stays locked, then it's either the caliper slide pins (if applicable) or caliper piston(s).

Share this post


Link to post
Share on other sites

thanks guys goty it worked out. as it turns out it was a combo of the lever barely touching the barkbusters and the screw adjuster being too far in. same on the other one as well as the hole on the cap being plugged.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×