Proportioning Valve question - front disk brake

[hzgray]

I recently installed CPP drop spindles, disk brakes, new master cylinder and proportioning valve. Very happy with it.

I bought the small plastic tool screwed into where the propertioning vlv warning light switch resides while i bled the brakes. Everything works fine.

Question: I have no need for a brake warning light on my '66 so can I just leave the "tool" installed rather than reinstalling the switch? It's a little cleaner looking in my opinion. Am I missing something? thanks.

[hzgray]

Hopefully I wasn't confusing. If I don't need the warning light/associated pigtail can I just leave the bleeding tool installed without impacting the function of the prop valve? thx

[compsystems]

I think the pin in the prop valve not only triggers the brake light, but also shuts off brake fluid flow to the side that may be leaking. If the valve was only for a light you wouldnt need to tool to bleed the brakes properly.

So if you leave the tool in place, and have a line break, It will continue to leak fluid and you may loose pedal pressure.

[hzgray]

Ok, I'm confused because I thought the two reservoirs on the master cylinder kept front/rear isolated from each other in the event of a leak. But it makes sense that the prop valve does something more than provide a place for a warning sensor. Thank you!

[oldman3]

Originally Posted by hzgray

Ok, I'm confused because I thought the two reservoirs on the master cylinder kept front/rear isolated from each other in the event of a leak. But it makes sense that the prop valve does something more than provide a place for a warning sensor. Thank you!

You are correct that the two reservoirs are for front/rear, but the prop valve is what lets the fluid go to the correct lines. This is really a combination valve, it meters the pressure to 2# to front and 10# to rear. It also controls fluid to keep you from locking up the front before rear or vise verse. Here's a cut away to show how it works. Hope this helps...Jim

[hzgray]

Question answered-thank you!