Force Required for Brake Lights

charlie55 · Post by **charlie55** » Tue Jun 10, 2008 12:59 am

Hi all:

This topic came up a while ago and I believe that I may be able to shed some light on it.....

While recovering from my spill, I figured that I'd tear the Blur down, check for any internal damage, and also do the "first service" myself. (Yes, I know about the warranty issue, but if you saw the "prep" job my dealer did, you'd know why I'm not gonna rely on their "expertise").

I noticed that the amount of "squeeze" needed to activate the brake lights has always been much less on the left (rear) brake handle than on the right (front). Once I got the headset off, the reason became apparent: the activating piston on the rear brake's master cylinder was recessed about a 16th of an inch further into its' bore than the one on the right. Don't know if this is a QC issue or what, but the net effect is that you only need to overcome the force of the handle's return spring to get the handle to the point where it trigger's the brake light. (In other words, the light comes on before you're actually applying the brake.) The effect is the opposite on the other brake, i.e., you're actually applying braking force before the switch is activated.

Just to even things out, I removed the front brake handle and carefully removed a tiny bit of metal from the surface that contacts the switch (if you hold the handle as if you're actually riding, this is the surface towards the front of the scoot). Stoned and polished it, and now the switch activation force required for both brakes is nearly identical.

Thought this might be of some help for those of you who like to do your own wrenching.

Regards,

Charlie

EP_scoot · Post by **EP_scoot** » Tue Jun 10, 2008 12:41 pm

Can you post some pictures?

That has always bothered me as I feel I have to press hard for the light to come up. Very annoying when you are blinking your brake light a few times on a stop light before applying full pressure.

charlie55 · Post by **charlie55** » Tue Jun 10, 2008 1:32 pm

Don't have a digital camera (yeah, I'm basically a Luddite at heart), but I'll see if I can whip up a diagram tonight.

-Charlie

EP_scoot · Post by **EP_scoot** » Tue Jun 10, 2008 3:04 pm

Great ! It doesn't have to be fancy.

I will be taking the panels off this weekend to add the Stebel, so it will be perfect timing.

charlie55 · Post by **charlie55** » Wed Jun 11, 2008 12:11 am

This is a generic image I copped off the web, so it's just to give an idea as to the relative layout of the brake handle (right-hand, front brake). That being said, here we go.....

"A" is the surface that contacts the plunger on the brake light switch, "B" is the approximate area in which there's a recess to hold the end of the brake return spring, and "C" is the surface that contacts the master cylinder piston.

When the brake is applied, the handle rotates clockwise around the pivot point, moving "A" away from the brake light switch and moving "C" towards the master cylinder piston. As pressure on the brake light switch is released, its' contacts close and the circuit to the brake light is completed. (The circuit that only allows engine starts when one or both brake handles are engaged is also activated.)

Now, as I stated in the opening post, my brake handle was engaging the master cylinder piston long before "A" had moved far enough to allow the brake light switch to close. My solution for this was to carefully remove material from the entire "A" surface, so as to give the switch more of a "head start" during the braking process. I also made sure to polish the surface and remove any imperfections caused by the filing/sanding. I then applied white lithium grease to "A" and "C", and the pivot point before final re-assembly.

Getting this just right is a matter of trial and error, so, if you're going to attempt this, make sure to remove material in very small amounts. Removing too much could result in your brake light being constantly "on", and, worse yet, unintentional overriding of the brake/starter interlock.

Hate to have to state this, but this explanation is presented for informational purposes only, and is neither an endorsement nor a recommendation for making the modification. Any safety/warranty issues rest with the party who performs the modification, and I assume no responsibility for same.

Regards,

Charlie

EP_scoot · Post by **EP_scoot** » Wed Jun 11, 2008 1:15 pm

Charlie55 wrote:
Hate to have to state this, but this explanation is presented for informational purposes only, and is neither an endorsement nor a recommendation for making the modification. Any safety/warranty issues rest with the party who performs the modification, and I assume no responsibility for same.

BTW, I am a Consumer Advocacy lawyer specializing on trials brought forth due to poor information provided to my customers . . . I have made lots of money for them !

Just kidding . . . Thanks for the pic and explanation, Very clear.