Thread: brake plumbing questions for my T bucket

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I guess my ultimate question is, "will a brake light preasure switch (T performance version) work properly between the proportioning valve and rear brake line Tee, after the residual valve?" I mean, if the residual valve holds presure at 10 lbs right? So what is required to activate the switch? I heard 7 lbs, in witch caes, my brake lights may stay on all the time, or flicker...
I plumbed the rear brakes out of the MC, to a residual valve, out of the residual valve into a proportioning valve on the frame, out of the proportioning valve into the brake light switch Tee, out of the brake light switch Tee to a SS braided flex line. Flex line goes to brake line Tee then to the drums... Will this work properly, or did I mess up? Front of course is a little more simple coming out of the MC into it's 2 lbs residual valve, out of the residual valve into a line Tee then off to the front calipers. Any advise before I bleed everything? Thanks to all in advance!

the psi switch need to be at the master not after the residual .

Originally Posted by pat mccarthy

the psi switch need to be at the master not after the residual .

i agree! with a duel MC you need a switch on both lines also.

Originally Posted by lt1s10

i agree! with a duel MC you need a switch on both lines also.

it's a tandem MC, does that make a difference?
OK, so I swap places with the switch and the 10# residual valve? can the proportioning valve stay between the two without any problems?

Thanks again guys for the quick response!

the way a duel MC and proportioning valve works is, if a front or rear wheel cylinder blows out then the proportioning valve will shut off the pressure to the wheel that has the problem, so you can still stop on the good brakes. if you have the pressure switch in the rear line behind the proportioning valve and the rear blows out and the pressure is cut off to the rear wheels then you want have any break lights. to have brake lights all the time you will need 2 pressure switched at the MC or 1 elec. switch.

Originally Posted by lt1s10

the way a duel MC and proportioning valve works is, .

does the same logic apply with a tandem MC as on the Dual? I thought a proportioning valve adjusted the fluid flow to the drums to even out the front-to-rear braking? thanks for the help.

we are probably talking about 2 dif. things. most factory GM cars put all this together and call it a combination valve. that would include the brake warning light, proportioning valve and the residual valves, but after i go back and read it i guess you don't have the warning light sw. (cut the pressure off if a cylinder fails )and thats the biggest reason to have a duel MC, so if one wheel blows out, the combination valve will cut the pressure off to that wheel, and you can keep on driving. i put a drawing in with this that show the cutoff valve. you don't have to have it, but without it you don't need the duel MC. see if the drawing helps any.

see if this makes more sense.

you can some were on the brake pedal use a arm type brake sw? they have them and they have a arm on them .should not be hard to get and work good

Originally Posted by lt1s10

most factory GM cars put all this together and call it a combination valve. that would include the brake warning light, proportioning valve and the residual valves,

That sounds alot like what I removed from the T when I did the upgrades...


Here are the components I have attempted to install...
part # WIL260-8419

part #'s WIL-260-1876 for the red 10lbs, and WIL-260-1874 for the blue 2lbs

(T Performance) part # BS1915

... and below are a couple pics of what (sounds like the all-in-one you mentioned) I pulled out (I cleaned it up for the pic )...

Originally Posted by pat mccarthy

you can some were on the brake pedal use a arm type brake sw? they have them and they have a arm on them .should not be hard to get and work good

hmmm. Thanks for the input Pat, respectfully, I am not sure I understand what you are describing sir. Can you explain?

Originally Posted by braundc

OK, so I swap places with the switch and the 10# residual valve? can the proportioning valve stay between the two without any problems?

Thanks again guys for the quick response!

Now the order goes like this...
REAR
MC to
brake line switch, to
prop. valve, to
10 lbs residual valve, to
flexline w/Tee, to
the rear brakes. Will this work?
FRONT
MC to
residual valve, to
Tee fitting, to rigid, then
front flex lines to
calipers...

this brake sw is work off the pedal movement and not brake pressure to make the brake lights work it has contacts that open and close. the circuit works to make you brake light up when you push on the brake pedal .it looks of where you have it is for the back brake port that is ok but you will have to T off it so you rear port can be used of you back brakes.

Originally Posted by braundc

That sounds alot like what I removed from the T when I did the upgrades...


Here are the components I have attempted to install...
part # WIL260-8419

part #'s WIL-260-1876 for the red 10lbs, and WIL-260-1874 for the blue 2lbs

(T Performance) part # BS1915

... and below are a couple pics of what (sounds like the all-in-one you mentioned) I pulled out (I cleaned it up for the pic )...

http://auto.howstuffworks.com/master-brake2.htm read this braundc, maybe it will make more sense. what you have is what i would put on my round track race car. the valve you took off is what i would have used on my st. rod. so i would have the "The pressure differential valve" that you dont have now.

ok, can someone please answer a stupid question for me? Bear with me here, I am new to this stuff, but, How do I make the actuating rod stay in the MC??? Am I wrong to assume it just sits in there without snapping into place somehow? Is the rubber boot supposed to cover the rod all the way to the threads, thus (kind of) holding it in place?? Do I need a stop pin or spring of some sort to keep my brake pedal from falling forward and pulling out the rod? Help! Thanks in advance!
the MC is a tandem wilwood aluminum, and the actuating rod is a T Performance 4 3//4 inch version.