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.

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...

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 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?

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.

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.

I'm not an expert.
but I drive a few cars (buick,chevy,ford,dodge )
and they all stop.
I'm not sure about all models but the ones I've worked on .
" Yes " it does just sit there ,the pedal holds it in , the rubber boot holds some "when new" but it's just a dust cover .
Sounds to me you need to do some adjusting /longer rod/a stop on the pedal / something (quote > to keep my brake pedal from falling forward and pulling out the rod) . hope that helps.

T L

should I use a stop pin type deal, or a spring thingy? above the floor or under? thanks for the help here folks!

You should have a return spring on your brake pedal, so that after you apply the brakes and then take your foot off the pedal, the pedal returns to a "no brakes on" position. There should be a positive stop to prevent the brake pedal from returning too far, or yes, your brake actuator rod that goes into the master cylinder will indeed "fall out". The correct way to set things up, is to have your brake pedal held in position against this "positive stop" by the return spring, (brakes completely "off"). The clevis end of the "brake actuator rod" is attached to the brake pedal "lever" . Loosen the jam nut next to the clevis, and unscrew the rod untill it is seated in the back of the piston in the master cylinder---not seated hard enough to actually move the piston, just in contact with it.---Then turn the rod back the other way about 1/2 turn. Then tighten the jam nut against the end of the clevis. Now the rod can not fall out, because the pedal can't move back any farther (remember, its against the return "positive stop"). There are about 400 ways to make a "positive stop" for the returned position, ---one of the easiest being a spacer welded to the top side of the brake lever that will contact the underside of the floor.