Swapping the brake light switch on Atom 2

[Peter255]

Got a new one in the post from the factory.

Is it as simple as unscrewing the old one from the brake cylinder and replacing?

I have shorted it out to check, and its definitely the switch (and the lights work).

Anything to watch out for?

Cheers
Peter

[John Scherrer]

As this is a brake fluid pressure-activated switch, brake fluid will/may escape and you will need to bleed the brakes after re-fitting. As the switch is pretty near the top/highest point of the system you shouldn't lose much fluid.

Take care to protect any paint etc as the fluid is highly corrosive

Disconnect existing wires
Place receptacle/rags under to catch any escaping brake fluid - Don't press the brake pedal!
Remove existing switch
Replace new switch - Shouldn't use any PTFE tape etc ..
Reconnect wires

Bleed the system.

[smokin]

Has the original one failed?

Many have said (me included) that the pressure-based switch isn't sensitive enough. Wouldn't want to go through the replacement process if the result is no different

[Peter255]

Well stamping on the pedal does not turn on the brake lights. Shorting the wires from the switch does turn the brake light on. Seems pretty clear to me unless I'm missing something.

Not keen on bleeding the brakes! That was my concern! Hmmmm. 

Peter

[smokin]

I agree, that seems pretty clear.

I'd use the bleed nipple on the top of the cylinder to bleed the air

[John Scherrer]

It's true as other have found, that changing the switch may not improve things, wheres some have found it does improve things. The lights should come on if the pedal is pressed hard, so iftey'r enot it does need changing.

The 'problem' is that the Atom is very light and together with the low gearing, lifting off the throttle even in top gear causes a rapid speed drop, so on the road we are really just tickling the brakes - not enough to operate the pressure switch.

I'd prefer some kind of throttle pedal proximity switch arrangement where a small initial pedal movement operates the lights.

A search on here will show a number of threads about this and some interesting solutions too.

[Peter255]

[quote="smokin"]
I agree, that seems pretty clear.

I'd use the bleed nipple on the top of the cylinder to bleed the air
[/quote]

I shall investigate. Sounds much easier than bleeding from the calipers! All may not be lost!

Cheers
Peter

[Peter255]

Switch swapped with little fluid lost.

Had a minor explosion of fluid when the pipe cam off mid bleed, followed by much cleaning and a hose down to be sure no fluid was left on the paint.

Tiny nipples suck!   

A good few squirts of fluid came out clean with no bubbles but there definitely some air in there. I reckon you can hear it when I depress the pedal as a little hiss / "squirt noise" Pedal feels OK tho. Pretty hard tbh. Fine to drive you think? I'm sure it'll be OK for road use, it feels find on a short road test. But I have a track day booked in a few weeks...