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Brake light switch - defective?

bosco659

bosco659

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While riding home tonight in the dark, I noticed my brake light wasn’t coming on when I applied the front brake. It was working fine with the rear brake. I stopped at the side of the road and found if I squeezed the brake lever, the light would come on. The large front brakes I have on my bike, have such great stopping power, that only light pressure on the brake lever will quickly bring the bike to a stop. Trouble is, that amount of hydraulic pressure isn’t enough to actuate the brake light switch. While riding, if I apply the brake hard enough to make the light come on, I’m nearly going over the handle bar. Does this sound like the switch is bad?

The switch is an integral part of the banjo bolt at the master cylinder. Bad picture.

IMG_1980.jpeg
 
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Possibly faulty, how did it function before or is this a new development.
Mot master cylinders have a lever actuated switch have a look at yours and change the wiring to use that. You could also buy a new hydraulic switch and try that, the switches are not expensive.
 
Signal said:
Possibly faulty, how did it function before or is this a new development.
Mot master cylinders have a lever actuated switch have a look at yours and change the wiring to use that. You could also buy a new hydraulic switch and try that, the switches are not expensive.
Click to expand...
Not 100% sure if it’s always been like this. I’ve always tested it by squeezing the brake lever and looking at the light (while stationary). I would imagine when I’m riding with a group that someone would lmk the light wasn’t coming on. I think a new hydraulic switch would be the easiest fix and as you note, they aren’t overly expensive.
 
Get rid of one caliper.
Send me a PM for my ship to address. :sneaky:
When's' the last time the fluid was changed?
I have a hydraulic switch mebby going on the 73 but that will be single caliper. (it's on the lift now) results by Monday?
Kinda related; Allison complaining her front brake on Ol' Paint is weak, 10mm MC, late model rotor stock caliper, pads???. Took it around the country block yesterday, she was right it wasn't very strong lever a bit spongy, I really reefed on that brake, prolly 10 hard stops from 60MPH. By the time I got back, the stainless rotor was dark steel blue and brake was firmer and more positive. Glazed from only light use? Dunno.
 
gggGary said:
Get rid of one caliper.
Send me a PM for my ship to address. :sneaky:
When's' the last time the fluid was changed?
I have a hydraulic switch mebby going on the 73 but that will be single caliper. (it's on the lift now) results by Monday?
Kinda related; Allison complaining her front brake on Ol' Paint is weak, 10mm MC, late model rotor stock caliper, pads???. Took it around the country block yesterday, she was right it wasn't very strong lever a bit spongy, I really reefed on that brake, prolly 10 hard stops from 60MPH. By the time I got back, the stainless rotor was dark steel blue and brake was firmer and more positive. Glazed from only light use? Dunno.
Click to expand...
Fluid was changed at the end of last riding season. Methinks it must be the switch. I have noticed the front brake isn’t engaging as smoothly as is usually did. It feels like a warped rotor on a car - getting some pulsation (not at the lever but it’s not as smooth as it used to be) - maybe better described ad a bit “grabby”. The only thing I did this year was remove the pads for inspection. Maybe I’ll service the calipers and maybe deglaze the rotors. I’m 99% sure the rotors are not warped.
 
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In my experience brake switches rarely fail.

The dozen or so I’ve taken apart because they didn’t work have all been due to bad contact.

It may be worth pulling apart, and cleaning.

Depending on how the switch operates, it can possibly have the lever shimmed or the actuator pin shortened.
 
WideAWAKE said:
In my experience brake switches rarely fail.

The dozen or so I’ve taken apart because they didn’t work have all been due to bad contact.

It may be worth pulling apart, and cleaning.

Depending on how the switch operates, it can possibly have the lever shimmed or the actuator pin shortened.
Click to expand...
The switch is a pressure sensor and I’m pretty sure it’s not serviceable. I’m away for several days but will have a look at it when I get back home. Thx
 
bosco659 said:
Thx. The current switch is hydraulically actuated so there’s nothing to shim.
Click to expand...

I had an XJ650 that I resurrected earlier this year, both the front and rear brake switches needed to be cleaned. I did order replacements but I recall they were not that hard to pull apart and clean till the fleabay replacements came in. Don't recall if it was the rear or the front that its contacts that rub along a cylinder and that cylinder was gunked up.

I can't recall, is there a free play adjustment on the brakes?
 

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