Front Brake Lockup

[Oregonian]

I have a 2017 DCT I purchased new.  Twice now, 200 miles of riding in between events, the brakes have locked up hard.  The front brake lever does respond to pressure and I have been able to pull over to the side of the road safely. I reset the ignition, and the bike seems to act normally.  When it happened the first time, I coasted immediately to the side of the road.  I wasn't even sure it was the brakes and thought it might be the DCT malfunctioning or the driveshaft.  The second time, I had to apply throttle to move further up the road and pull over.  That time, the brake smell was strong and the front rotors were very hot.  There is plenty of brake fluid in both the front and rear reservoirs. 

I plan to take it to a local dealership, but have never seen this type of brake problem.  Doe anyone have any ideas?  I'd like to know what I might be in for regarding solutions and repairs.   

[Hartley]

There are several posts relating to odd brake issues on this site. ( Do a search and have a look) I’m not sure if there’s ever been a definitive answer. I’ve heard a brake fluid change can help but I’m not sure why 3 or 4 year old fluid would cause this sort of problem.

[DaveinNC]

Do a thorough and complete flush of the abs system. My bike was new, old stock. It sat in a crate for a few years. Apparently, the ABS unit is sensitive to old brake fluid. I flushed mine with speed bleeders and about 2 quarts of fluid then cycled the abs unit in wet grass several times. It hasn't happened again since and it's been almost 4 years.   

[Showkey]

If the compensation port is blocked in the master cylinder……..the brake pressure will NOT be released.


The port is small……debris can block the port.

[Oregonian]

I picked the bike up from the mechanic.  He flushed out the system according to the service manual directions.  The brakes bite much better and I haven't had a lock up.  Granted, I have only ridden about 30 miles, but there seems to be an improvement.

I guess the theory is that old brake fluid could allow water to enter the system and create extra pressure on the pads that appears randomly.

I'll report back here if anything recurs. 

[DaveinNC]

In the majority of these cases, this is all it takes. A good flush and fresh fluid and it never returns. I'll be flushing my system every year. Add speed bleeders to the calibers and it's a 30-minute job.