Brake Switch Question - 55 Wagon

[scorpion1110]

So......

I am wiring the 55 Wagon and I need an opinion.

The Wilwood prop valve has its own pressure switch for the brake lights. I am thinking about eliminating the pedal switch and just going to the prop valve. The harness has the wires so its an easy hook-up. The question is, which is the better choice?

Seems simpler using the pressure switch; no switch adjustment at pedal and you arent squeezing under the dash.

Any reason one way is better than the other? I am leaning towards the pressure switch.

Scorp

[chevynut]

The brake pedal switch turns the light on as soon as you depress the pedal some set amount, depending on how the switch is adjusted. A pressure switch has to have pressure to turn the light on, so you have to be actively braking. I prefer the pedal switch myself because the light comes on even if you're pushing on the pedal, but not enough to build pressure. I think the pedal switch would work better with cruise control so the switch disengages it before you actually get brake pressure. Of course they could be adjusted to work exactly the same if you wanted the pedal switch to turn on later. But since it's already wired to use the pressure switch, it should work fine and I don't think you have cruise control. ;)

[Rick_L]

If you're talking about the Wilwood prop valve that emulates a GM combination valve but is adjustable - the switch is for a warning light that shows one end of the system is not making pressure due to a leak. It is not intended to use as a brake light switch and won't work for that. I have one of those valves and I think it's a good piece to use, just not for that.

[chevynut]

If this is the one, it has a brake light switch...

https://www.performanceonline.com/wilwood-disc-brakes-adjustable-proportioning-valve-and-bracket/

https://cdn.performanceonline.com/images/T/WPV001_S.jpg

[Rick_L]

No it doesn't. You have to decide whether to trust me or performance online. It's a warning switch just like a GM combination valve has.

[BamaNomad]

I haven't used one of these POL parts, but I'm with Rick on this one. It doesn't make sense to sense pressure at that valve in order to turn on the brake lights! What does make sense, and what every combination valve I've seen does is have a differential switch which senses loss of pressure (or lower pressure) for either the front or rear brakes relative to the other and turn on a BRAKE WARNING LIGHT. That is the only 'brake light' that part should turn on... a Warning Light!

Here is a good reference for combination valves and what they include:

http://www.camaros.org/brakevalve.shtml

[chevynut]

No it doesn't. You have to decide whether to trust me or performance online. It's a warning switch just like a GM combination valve has.

Well I trust Wilwood to know how their product works, even if it "doesn't make sense" :p....


https://www.wilwood.com/Images/MasterCylinders/MasterCylinder_Drawings-Large/260-11179_dwg-lg.jpg


Wilwood's install directions:
"a fluid port with a pressure switch responds instantly to pressure in front fluid circuit for brake light activation". "....if you wish to eliminate the switch on the brake pedal, use the switch in the proportioning valve block".

https://www.wilwood.com/MasterCylinders/MasterCylinderProd?itemno=260-11179

[Custer55]

On the Wilwood website it is called a pressure switch. Also if is an adjustable proportioning valve, not a combination valve. The front and rear brakes are isolated from each other with the Wilwood valve so I don't believe there is a brake warning light switch function built into it as the pressure switch will only see pressure from the front of the master cylinder.

[scorpion1110]

I am pretty sure its a pressure switch to activate the brake lights. My 57 Tbird had one in line doing the same thing.

Here is the text from Wilwood:

Switch Connections: If your vehicle is already equipped with a brake light switch on the brake pedal, the switch in the combination valve does not need to be used, and it may be removed. Plug the unused port with a 1/8-27 NPT pipe plug (not included). For all other applications, or if you wish to eliminate the switch on the brake pedal, use the switch in the proportioning valve block. 1. Before connecting the lead wires, cut the ends (that do not have the clip) on a 45° angle. Coat both cut ends with Dielectric Grease to ease sliding the wires through the holes in the dust boot. Slide the clips onto the spade connectors and cover with the dust boot. 2. Connect one lead of the brake light pressure switch to a 12 volt, 15 amp fused circuit. This should be a battery direct, always hot circuit. Do not use an ignition key switch activated circuit. 3. Connect the other pressure switch wire to the lead wire going to the brake lights. 4. Be sure the brake lights are properly grounded, and all connections are secure and insulated.

I am pretty sure it is to replace the switch on the pedal which activates the brake lights.

Scorp

[Rick_L]

Looks like I was misinformed. Apologies for any confusion it may have caused.

[BamaNomad]

Appears both Rick and I weren't up to date on this Wilwood part, as both he and I responded based on the standard 'combination valve' functions, and I suppose he, like I, responded as we did due to the great amount of misinformation/misuse of the typical combination valves that are sold.

[scorpion1110]

Gentlemen,

I appreciate the dialogue and everyone's help.

Scorp