Hydraulic brake switch

The Sock said:
It should make a circuit when pressure is applied to the brake lever.
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Ha! I'm sure Paul will see the humour in that response ;)

Paul, you mean like using a multimeter in some way? Doubtful, because unless you have a closed circuit (like when the brake lever is squeezed) there's nothing to measure - it's just two electrical contacts that touch when hydro pressure brings them together. I tested my aftermarket one off the bike by poking a small rod up it's cloaca and creating that pressure by hand and the multi sounded off to confirm a circuit.
 
piranha-bro2 said:
If it's connected and full of fluid and not working ... you'll have to take the f...ing thing off again anyway. :cool:
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Looks like it, only it's one of those jobs with consequences.
One of the bleed nipples is about to strip its thread so it means at least one caliper out, a 6mm tap down the bleed hole and if that doesn't do it, a 7mm tap and 7mm bleed screw.

I'm beginning to dream of brake fluid. In the last couple of weeks, I did my wifes 500, then my 3C and then my SF2. New pistons, seals and master cylinder pistons and seals.
I've had quite enough.

Paul
 
Paul,
you have a bike to compare, right? the brake light switch works on the SF2, but not on the 3C.
Hook up your multimeter to the SF2, the restistance setting should display some value when the brake lever is pulled.
Repeat the exercise on the 3C and see what you got. If the reading doesn't change, your switch has an issue.

Gerald
 
Gerald said:
Paul,
you have a bike to compare, right? the brake light switch works on the SF2, but not on the 3C.
Hook up your multimeter to the SF2, the restistance setting should display some value when the brake lever is pulled.
Repeat the exercise on the 3C and see what you got. If the reading doesn't change, your switch has an issue.

Gerald
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Thanks Gerald, will give it a try.

Paul
 
Looks like a wiring issue. I have no rear brake light switch on at the moment and the circuit appears to be fed from there.

Paul
 
dja982 said:
Why not bridge the two wires if it lights the brake light its the switch if it doesn't its the wiring
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There's 3 wires. 2 grey ones from the switches and a black live feed.
The light will come on by bridging black + 1 grey but not black and the other grey.

I'll wait until I have a rear switch wired in before jumping to conclusions.

Paul
 
Presuming you have sufficient fluid in the system to develop pressure when you apply the brake lever, then there's no need to remove the switch to test it. It's a simple matter of putting a meter across the spade connectors on the switch. Use the lowest Ohm scale. Some meters have an audible beeper to indicate continuity when the resistance is below a few Ohms, which makes life easier because you don't even have to look at the meter.
Brake not applied - meter reads infinite resistance.
Brake applied - meter reads zero Ohms. Don't worry if it's not exactly zero. Most meters aren't perfectly zeroed.
 
Dellortoman said:
Presuming you have sufficient fluid in the system to develop pressure when you apply the brake lever, then there's no need to remove the switch to test it. It's a simple matter of putting a meter across the spade connectors on the switch. Use the lowest Ohm scale. Some meters have an audible beeper to indicate continuity when the resistance is below a few Ohms, which makes life easier because you don't even have to look at the meter.
Brake not applied - meter reads infinite resistance.
Brake applied - meter reads zero Ohms. Don't worry if it's not exactly zero. Most meters aren't perfectly zeroed.
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Thanks.
Looks like nothing is going to happen until I wire in a rear brake switch anyway, it's an integral part of the circuit, both switches being on the same circuit.

Paul
 
Connect your multimeter on to the two connectors on the switch and have it on ohms. Push the brake pedal. If its an analogue meter you should have a full scale deflection, if its digital it should be zero (or very low) ohms.
 
natm said:
Connect your multimeter on to the two connectors on the switch and have it on ohms. Push the brake pedal. If its an analogue meter you should have a full scale deflection, if its digital it should be zero (or very low) ohms.
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Thanks, will do as soon as I have a rear brake switch wired in. I've just ordered a Honda one, €5. Will wire it in next week and see what gives.

Paul
 
Paul Marx said:
Thanks.
Looks like nothing is going to happen until I wire in a rear brake switch anyway, it's an integral part of the circuit, both switches being on the same circuit.

Paul
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I don't understand where your thought process is leading you Paul. The front and rear brake switches are wired in parallel so one will still work without the other switch being present. Testing with a meter is best done with the wiring disconnected anyway. So the entire wiring harness can be in another room for all the difference it'll make.
 
Dellortoman said:
I don't understand where your thought process is leading you Paul. The front and rear brake switches are wired in parallel so one will still work without the other switch being present. Testing with a meter is best done with the wiring disconnected anyway. So the entire wiring harness can be in another room for all the difference it'll make.
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Ok.

Paul
 
That's sorted. It works when a rear switch is plumbed in.
Just the day a new hydraulic switch arrived in the post.

I forget who recommended a Honda rear brake switch. An excellent tip and all for the price of a beer.

Paul20 6 21.jpg
 
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