My front break lever is loose. I noticed a plastic piston inside the master break that pushes the lever outward. Noticed it doesn't fully come out. Any clues to what causes this. How so I check it, does it screw in and out? Is it a spring I should replace?

This causes:

1)my lever to be loose
2)the breaks light to stay lit all the time I ride as if my breakers where pressed as the switch isn't fully pushed in.
3) after riding for a while this causes my alarm warning light to light up letting me know the break is "pressed or lit"

Fortunately my bike seems to be stoping fine, but want to diagnose this.

Note: I've been ruling out the micro-switch.

Thanks as always

 

You might try flushing with fresh brake fluid.
Next thing to try might be a master cylinder rebuild kit.

 

This sounds like the trigger for the BRAKE lights. According to the service manual they are easily damaged so it sounds like a rebuild is in the works for you. Personally, I wouldn't ride the bike if there is something wrong, not worth the risk especially when it comes to brakes.. If you are mechanically inclined and own a service manual do it yourself, otherwise bring it to a shop to get it fixed.

 

Could be a sticking master cylinder piston. WD40 may be a temporary fix, at least to see if that's the problem. The plastic plunger is the brake light switch which is not making contact because the lever is not going all the way back.

 

That "piston" that touches your lever is in fact the brake light switch and if you disconnect your hand control without placing a shim to prevent the handle from closing all the way, then most likely your broke it and need to replace it. Have a look at your service manual.

 

And to note, the only thing that "pushes" your handle is hydraulic pressure from the brake system. As another mentioned, check your brakes, maybe the puck(piston inside of caliper) is sticking or you have a clogged port in your master cylinder. If the brakes are old, time to rebuild with all new rubbers and emery cloth the puck unless it is pitted in which case replace that too. Your life is at stake here man....just saying.

 

I want to know when you push your brake lever open does the brake light go out? If it goes out then you will need a rebuild kit for that little pump in the bottom of the reservoir. Nobody can explain it, they don't show signs of wear but when that happens you can play with it all you want and loose time or replace it and boom your fixed.

On the other hand if you press your lever open and the light does not turn off you will need a new micro-switch inside the throttle housing.

 

I have the same problem. Had a state inspection tech point it out to me a few months back. I didn't think anything of it, as my braking ability is a strong as ever, but my brake light only goes off when I push the brake lever forward. Thanx for the info, now that I now what I'm dealing with I'll have the techs take a look next time I drop it off for service, which be very soon. Last thing I need to do is try to fix it myself, having 'extra parts' after a brake job is not a reassuring feeling.

 

LAFO. .before you go messing around with a rebuild kit, etc. Get a can of silicone spray lube and spray that plunger and work it in and out with the lever. I think you'll find it'll fix your problem. My M/C was replaced under warranty for same issue, which fixed it. Problem was starting to slowly return so I used some silicone grease I had around (used for brake caliper parts) and smeared it in there and worked the lever. Immediately I noticed an improvement, and over the next day or two it only got better.

Rubber dries out over time and becomes less flexible. I believe this to be the reason this happens on our bikes. Recently worked on a friends EVO Softail and found the old system did not have this issue. Strong spring in there forces the lever out fully. Our bikes rely on the hydraulic return pressure to push the plunger of the M/C out which returns the lever to its normal position. Not nearly as effective I think.

 

Do you only have the break problem when the high bean is on?