2008 FLHTCU
Last week I removed my front brake calipers and wheel to get to the underside of my fender. I only removed the mounting bolts and slid the calipers off, resting each one up over the highway bar and on the pedals of each side. The bleed fitting remained in upright position and no undue stress was placed on the brake lines.

After reassembling the front end, I started having strange front brake behavior. First, I lost all braking in the front end but then it would feel tight again. As soon as I finished my ride I used a mightyvac to bleed both calipers. There seemed to be a little air in the right caliper but I didn't see anything in the left. The lever felt nice and solid so I took it back out for a test ride and it was fine for a couple brakes. Then my front brakes were "engaged"; they were gripping the rotors pretty tight. When I pulled in on the clutch to coast, I came to a stop; not a screeching stop but 35mpg to 0 in 20 feet rather than coasting in neutral. On the return ride home it seemed to randomly choose between no brakes, good brakes, weak brakes and engaged brakes.

There are absolutely no leaks anywhere around the lines, calipers or reservoir. Specs for an '08 Ultra call for DOT 4 fluid which is the only thing I use in it. Pads are still good, rotors are decent.

Any ideas?

 

I suspect the piston in the master cylinder is binding? I would consider a rebuild kit as well as a system flush.

 

Thanks mmesa005! I'll give that a try.

 

Unfortunately, that didn't work.

I flushed the system of the old brake fluid making sure there was nothing but new in the lines. Then I removed the Master Cylinder and rebuilt it. After putting it back on, I flushed the lines a second time assuring I had no air in the calipers/lines. When I was finished the hand lever was nice and tight. I took it out on road and it braked fine at the first stop. The second stop I had no brake at all - had to rely on my rear brake. When I got to my third intersection I pulled in on the clutch and noticed my front brake was grabbing - I slowed down way faster than a normal coast. Turned around and went home. When I pulled into the driveway, the front brakes were working like a charm again.

Ideas?

 

Take a look at this thread.. I would go back and check the master cylinder for any contamination and then take a look at the calipers and brake rotor for any warping.

https://www.hdforums.com/forum/frame...-behavior.html