Brake Light Switches - fluid type.

[Route666]

Can these brake light switches like the ones on this page http://www.painlesswiring.com/webcatalog/cat-switches.htm be used for a hydraulic clutch? Would there be enough pressure in the clutch fluid for the low-pressure version of the switch? You could make a neat "will only start with clutch pushed in" feature.

 

[Route666]

Awww c'mon someone's gotta have some experience with these switches.

 

[Edbert]

No idea on the brake-switch, but have you bypassed the neutral safety switch?

 

[Route666]

Well I wasn't talking particularly about Mustangs I guess, just hydraulic clutches in general. Is there a neutral safety switch on older manual trans'? I've only seen them in autos.

 

[limey66]

Never seen one on a manual trans vehicle. I guess you could use one that way, but why? A good start up drill will prevent you charging forward into a cinder block wall... I always start cars with the clutch down.

Surely it's just something else to go wrong...?

 

[Edbert]

I have an aversion to splicing hydraulic lines more than necessary. Why not use an electric switch like new cars have?

 

[Route666]

Well gentlemen, here's my ideas:

A good routine is what I have, it's simple, play with gearstick until you're sure that you're in neutral, handbrake on. I always park that way (unless on a hill) so there's not much chance of me starting in gear anyway, but it's one of those quirky modern car features I'd like to add. Might help baffle some thieves too, if used in conjunction with EFI that is, not just the starter solenoid / relay.

I agree that splicing more stuff into hydraulic lines is adding more potential problem points, but it seems to me a more correct solution than fabbing up a bracket or mounts for a switch / drilling holes in things. Ok so new cars might have electric switches but they were designed in there, not an afterthought, so retrofitting one would seem a little tacky, to me.

I'm like neat stuff like nifty switches, etc.

There would be enough pressure in the clutch line to trigger the switch right? They're meant to trigger at light braking touch so clutch actuation should have at least that much pressure.

 

[Edbert]

There would be enough pressure in the clutch line to trigger the switch right? They're meant to trigger at light braking touch so clutch actuation should have at least that much pressure.

That's the crux of the issue...how much pressure is actually in the clutch line?

In general all the hydraulic lines would pale in comparison pressure-wise to the braking system. But if the switch were to actuate at a low pressure it might work fine. Can you attach a gauge to the slave cylinder and find out how much pressure is actually in the line at full depression? I'm sure the manufacturer of the switch can tell you the actuation figure. If the line has more than that your all set

 

[Route666]

That would give an absolute, without a doubt answer, but I'm not that keen to ask just yet, and the way I see it, pushing the clutch pedal on any car I've had is harder than the pedal effort required to turn brake lights on, which should happen with the slightest braking, so it should work. Clutch MCs have around the same bore as brake MCs too right? Which means the pedal effort for each (as long as pedal ratio is the same as well) will be the same for the same line pressure.

Anways, I now believe it would work, but I'm not too fussed on actually doing it, and wouldn't be too worried if it didn't work, except for the wasted effort.