Gen 5 Front Brake issue.

Hello everyone ,
I went to the bike this morning and the brake lever went all the way to the bar with no resistance and no breaking. There are no obvious signs of a leak, and the master cylinder shows fluid. What could it be? Thanks.

 

My thought would be to start at the top and work your way down. Check the master cylinder seals first. I assume
it has been working, and with no evidence of leakage anywhere, that would be, to me anyway, the obvious place to
start. Don't spill any fluid, it's very hard on paint and plastics.

 

I agree with that diagnosis, sounds like the seal on the master cylinder piston has failed e.g. a crack or some debris is caught in it. A master cylinder rebuild kit is pretty cheap and easy to use. When you clean the master cylinder casting make sure that the relief ports in the floor of the cylinder are BOTH clear.

 

anybody do work on the bike recently ? sometimes even if the brake lever has no feel it can be pumped back up [temporarily] with a few lever releases and pumps.

 

No one has worked on the bike and I tried pumping the lever, it’s not restoring the pressure.

 

I had another look and it looks like little bits of something like white crust where the lever pushes into the master cylinder.

 

not your problem. get the cap off.

 

Today is the day I got the bike on the work stand all parts in hand. I figured I would check the rear reservoir……bone dry. No signs of a leak anywhere.

 

The good thing about that is that you will not have to clean up a mess of old brake fluid when you rebuild the rear master.