Front Brake Problems

[KTM CHRIS]

The front brake on my 2000 200 gave me a interesting problem this last weekend. I had previously put new pads and fluid in the system. Bleed it and the brakes felt good (In relation to KTM brakes). Was riding this weekend and after about 2 miles I noticed that the front brake lever was getting tighter and that the front brake seemed to be dragging some. Well I though OK get back to the truck quickly and see what is wrong. On my way back the front brake continued getting tighter and finally locked up and almost took me down. I pulled the lever in the little that it would and released some fluid at the bleeder. This helped the situation for about 2 more miles with the same scenario playing out again with the lever getting tighter and then the brakes locking up. Bleed again and it seemed a littler better than after the first time. Finally it made it all day after doing this three times. It still got a little tighter as I rode but no more lock ups. What is going on? It is as if the fluid is expanding and pushing the pistons out of the caliper and pushing back into the reservoir. Thanks for any help in advance.

 

[Jeff Gilbert]

Did you use Dot 4 fluid? Or perhaps you got hold of some brake fluid that had some moisture in it.

 

[Unit74]

Sounds like water or air heating up. Also, you could have a pad dragging aggrivating the problem

 

[marcusgunby]

Check to see if the plunger on the master cylinder is fully retracting-it needs to have some free travel.

 

[biglou]

This happened to a guy I work with a couple races ago. Exact same bike, year and size. He had just topped off his res. and after a few miles, the front locked up on him. He would sit for a few minutes, then go another couple miles until it locked up again. My guess is that it is over-filled, causing the fluid to expand until it has nowhere to go but to squeeze the front caliper,essentially applying the brake uncommanded. Make sure you are within the marks (If there are any) on the sight glass window. I would run it at no more than 2/3-3/4 up that window. Also, if you run your lever at an angle, loosed the clamp and rotate it so that the res is horizontal when you check your measurement in the sight glass. After you close it back up, then return it to where you like it.

 

[KTM CHRIS]

Thanks again for the replies. I am going to get a new bottle of fluid and start over. It might be that that reservoir had to much fluid as the sight glass is solid with fluid. Glad this was only a ride and not a race.

 

[John 300 EXC]

This is a good sign; that you are actually using the front brake!
I suspect too much fluid in the reservoir. Where were you guys riding?

 

[ktmracer]

my 200 did the same thing after i had screwed the adjuster all the way in on the lever. all i did was just back out the adjuster and no more problem.

will