Drum Brake Distribution Block

[pist0lpete]

Yes. http://www.wilwood.com/MasterCylinde...inderKits.aspx

I believe the switch you see there is a brake light switch not a brake warning switch. The warning switch works off a shuttle valve inside the factor distribution block. If for some reason pressure is lost(read a leak) in the front or rear system, the pressure differential moves the shuttle valve over closing off the leaking side of the system. This activates the warning switch.

[JustJohn]

That's what I initially thought as well so I called Wilwood and spoke to a tech. Even after re-reading their instructions I'm confused. Either the install sheet is completely wrong or the tech was, which complicates things as I just finished fabricating/rerouting brake lines.

I'll be checking again now that there's conflicting info from Wilwood.

If I hear differently after a second call, I'll make sure to clarify.

[JustJohn]

That's what I initially thought as well so I called Wilwood and spoke to a tech. Even after re-reading their instructions I'm confused. Either the install sheet is completely wrong or the tech was, which complicates things as I just finished fabricating/rerouting brake lines.

I'll be checking again now that there's conflicting info from Wilwood.

If I hear differently after a second call, I'll make sure to clarify.

I put in my second call to Wilwood and got some explanation which I think helps everyone (disclaimer: I work as an automotive design engineer so I get paid to break things and be wrong 90% of the time. Also I design fuel side components these days.). Here goes:

The GM disc/drum distribution block, which I also had, has a pressure differential switch that gives you a warning when it sees a pressure difference per the GM design pressures. That point is important because when you change the design parameters from what GM intended, the pressure differential switch is no longer applicable to your car. The prop valve feeds into the pressure differential switch, so if you replaced your fixed value prop valve and make an adjustment, you get a warning light because the pressure differential switch sees a pressure difference it was not designed for. I can't think of an easy way to get a pressure differential switch that I could re-calibrate every time I make a change, so I think I have lost my warning light function unless there's one out there that can be plumbed before the prop valve and is looking for equal line pressures.

So after my discussion with the Wilwood tech, the switch that comes with their metering valve is a pressure switch but will not function as a warning light. It's just a pressure activated switch you can use for brake lights if needed.

If someone who is more knowledgeable about brakes sees something wrong here, please correct me on it. I haven't filled my system with fluid yet so it's not messy making changes.