Intermittent Brake Light

[Erich Z]

I'm trying to make sure my bike is ready to ride and have a couple niggles to sort out. Tomorrow is my last day in MSF so the sooner I get it ready the better!

One of the issues I need advice on is a finicky brake light. It works great with the foot brake, but the front brake lever doesn't actuate it unless fully depressed, and then it flickers at times. Am I right in thinking it's probably the front brake switch? Is that something I can just clean or should it be replaced? How do I clean it.

I'm new to doing electrical work, so pretend I'm really stupid. I can solder though.

[focus frenzy]

dirty contacts and or out of adjustment, follow the wires under the lever into a small plastic bit with two screws holding it to the bottom of the lever mount/ perch.
it can be adjusted to control when the brake light comes on, you just loosen the screws and slide the housing and test till the brake light comes on just slightly before the brake starts to work.

you can also remove the screw and take the switch apart and clean the contacts but you have to be very very carefully as it contains very tiny parts that are easy to loose.

a trick is to place a small stool under the lever with a old pillow on it fluffed to make a bowl shape so any tiny parts dropped fall on the pillow and don't hit the floor and bounce off never to be seen again.

[Nessism]

Front brake switch on the master cylinder is pretty finicky. It's adjustable and prone to sticking. If you are pretty good with mechanical stuff very carefully take it apart and clean everything. You will have to adjust it carefully to get it to work properly. If you are ham fisted, order a new one and install - still needs adjustment.

http://www.crc2onlinecatalog.com/Index_Main_Frame.htm

[49er]

dirty contacts and or out of adjustment, follow the wires under the lever into a small plastic bit with two screws holding it to the bottom of the lever mount/ perch.
it can be adjusted to control when the brake light comes on, you just loosen the screws and slide the housing and test till the brake light comes on just slightly before the brake starts to work.

you can also remove the screw and take the switch apart and clean the contacts but you have to be very very carefully as it contains very tiny parts that are easy to loose.

a trick is to place a small stool under the lever with a old pillow on it fluffed to make a bowl shape so any tiny parts dropped fall on the pillow and don't hit the floor and bounce off never to be seen again.

There is limited adjustment on these switches. When I investigated why mine had stopped working the copper contacts had worn away and the assembly had disintergrated.
I sourced a NOS replacement on Ebay and it's now working fine. The new switches are also very finicky to fit up so use the suggested method above.

[SqDancerLynn1]

Do it right --- replace it with a Hyd pressure switch $20. Never have to worry about it again

[Erich Z]

Do it right --- replace it with a Hyd pressure switch $20. Never have to worry about it again

More info?

[chef1366]

Check here
With the search feature I found that in less than thirty seconds :-D