Home Feb 2010 Vol 10 - No 2
Feb 2010 Vol 10 - No 2 - Rear Brake Switch by Dave Wolf PDF Print E-mail
Written by Administrator   
Thursday, 04 March 2010 19:19
Article Index
Feb 2010 Vol 10 - No 2
Group Riding Formations- Cluster or Solo? By Ben Harper
The Valve Stem by Alex Ford
Fuel Pump Gravity Feed by Dave Wolf
Rear Brake Switch by Dave Wolf
All Pages


Rear Brake Switch by Dave Wolf

Recently my brake light has been staying on. I thought it was my wiring, as it had done this before, but the wiring was solid. Usually after a lot of fidgeting, once I got underway the brake light would turn off.  After much diagnosing, I finally narrowed it down to the switch itself. At one point the plunger didn't even retract into the body.
Being the guy I am, and also not wanting to spend $23 for it online when I can fix it for a pennies worth of grease, Q-tips and brake cleaner, I took it apart and fixed it myself.  Since I ride in harsh conditions (dust, dirt, rocks, bushes, water) my motorcycle is subjected to things far above what someone would experience in the city.
You will need needle nose pliers to remove the spring as it connects to the brake lever.  Leave the spring in the switch itself. It is curved so that it is difficult to remove.
One the switch is removed, peel back the rubber boot on top. This may take some effort, but it is not glued, and it's not really that hard.   After the boot is peeled back, (I apologize, I didn't take pics of this step) you will notice that there are two small "windows" opposite each other on the upper body of the switch.
You want to take a small, hard implement and push the metal tabs in these windows SLIGHTLY inward.  You want the tab to be flush with the body, that's it.
You can now pull the contactors out. They will not fuss too much, they come straight up and out. Needle nose pliers help a great deal with this.
You will notice there are two tabs that stick inward.  These tabs are what contact the metal sleeve on the plunger. Take a look at these tabs.  You may notice some corrosion, dirt, and dust on them. I used a very fine abrasive dremel polishing tip to restore my contactors to a nice shine and to remove some corrosion that had occurred due to water entering the switch.
Grasping the plastic body, position the upper portion of the body that the contactors came out of towards the palm of your hand. When you remove the spring from the switch, the plunger, upper and lower shims, metal sleeve, and spring will come flying out as an assembly. Don't worry, the idea is to catch the stuff in your hand, or at least prevent them from flying across the room.
Here is a picture of the guts removed. It's really very basic. I only have a cell phone, so the pictures are not as good as I want you to see.


Here I did my best to show you how the parts go back on the plunger. The plastic "shims" isolate the metal sleeve electrically, and act as insulators when the switch is in any position but "on". Each shim has a small lip on one end. The lips of the shims both face the metal sleeve. The metal sleeve slides over the lips of the shims, isolating it from the plunger. The spring prevents the switch from being on all the time.
When I first took it apart, dust poured out of it. When I shoved a Q-tip through it, a "capsule" of dust wash pushed out.


When you have cleaned the assembly up with brake cleaner and Q-tips, you can move onto the plunger. My plunger had significant corrosion, enough to feel with my finger. I cleaned it up with my dremel. I recommend taking Q-tips to everything. Remove the fuzzy part of the Q-tip and clean out the small shaft in the body where the plunger exits. Make everything really clean.
When you are sure everything is nice and clean, break out your grease. I used Green Grease, because it is tenacious, and will not go anywhere, hot or cold weather. I am hoping it keeps dust out, and provides for lubrication. I packed a bunch of grease into the body and shaft with a Q-tip. I also greased the plunger shaft to protect from corrosion.
Push the plunger into the body until you see the tip protrudes from the end of the body and re-insert the spring so the plunger doesn't go anywhere.
Here are the contactors I was talking about. In this picture I am ready to re-install them and the tabs are bent back outwards. They will click nicely in the windows, keeping the contactors snug inside the body. After the plunger is in place, bend the tabs back outward in the contactors and re-insert them back into the body.  Make sure the contactors both "click" in the body.


Begin rolling the rubber boot back down over the switch body. But stop before you have it completely down.
Here you can see that I applied a small bead of RTV silicone to the outer lip of the rubber boot. I have not fully pushed the boot down over the body. I don't want any more water in my switch.

In this final picture, you see the grease coming out of the body. I didn't wipe it away because I wanted it to act as a barrier. I also cleaned the bottom of the switch and applied RTV silicone, but I left the grease on the plunger shaft so that the silicone would not adhere to it. I am hoping this acts as a sort of seal for dust and water.
Now the switch activates instantly and also deactivates.  I cannot stress how dangerous this was. I only noticed it because my brake light flashes when it is applied. Who knows how long I had been riding with my brake light on. This creates an awfully dangerous situation when riding. It was a quick and easy fix. I wish I had a better camera.  Thanks for reading.

Last Updated on Friday, 05 March 2010 12:54
Copyright © 2018 I.S.R.A. Star Cruiser E-Zine. All Rights Reserved.
Joomla! is Free Software released under the GNU/GPL License.