Question about dual bowl conversion

472viper

Member
Oct 17, 2019
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Sioux Falls SD
64.5 coupe 170 ci automatic. Looking at kits online to do a dual bowl master cylinder conversion. The single bowl that is on my car now has two wires running to a switch on the bowl. I assume this is for brake lights ? As I look at the conversion kits none of them seem to have this switch. What do I do to the wiring ? Is this unique to 64.5 ?
 
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rbohm

SN Certified Technician
Apr 12, 2002
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you dont need a kit to do the conversion, just a few bits of kit. start with the 67 drum/drum master cylinder. next you are going to need some brake line. you can get it already setup with fittings and flares from most parts stores, they will be straight though so you need to bend them up yourself, easy enough to do, in fact if you are careful you dont even need a tubing bender. i didnt when i did this conversion on my 64 falcon.

you will also need a "T" fitting that you can use to mount the stop light switch. i think its a 3/8" pipe fitting, but it has been a while since i did this conversion. you will also need fittings to screw into the "T" that have the proper SAE fitting for teh brake line, that will also screw into the "T" fitting.. you may also need adapter fittings for the master cylinder as well, i did. you dont need teh distribution block though, or a proportioning valve either if you stick with the drums all around. you will also need a couple of plugs. the stock distribution block has three outlets you only two of them for the front brakes, so plug the third one. also you need a proper coupler to splice the rear brake line to the one that comes from the master cylinder. again a straight through fitting with the proper adapters like you use on the "T" fitting will do nicely.

take your time a measure the length of lines you will need, and dont forget to add a few inches to each line to allow for bends.

one more suggestion, when you are buying these bits, step up and buy the wheel cylinders from a V8 mustang and install them on your stang. this will upgrade you wheel cylinders, and actually give you some improved braking due to the large wheel cylinders. nit a great deal, but it is noticeable, at least it was on my falcon. the nice thing is that teh wheel cylinders bolt in place of the stock six cylinder ones.
 
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472viper

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Oct 17, 2019
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Sioux Falls SD
WOW !! Thank you for such an informative write. Everything you said makes sense, move the switch to a "T" fitting and run the lines from there. I like the suggestion of the improved wheel cylinders. Thanks again !!
 

rbohm

SN Certified Technician
Apr 12, 2002
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anytime :D:D i dont have a working digital camera anymore, otherwise i would take pictures of my conversion and post them for you to examine.
 

rbohm

SN Certified Technician
Apr 12, 2002
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i ordered a new digital camera, and it should be here in the next week or so, so when it comes in i will get pictures of my conversion for you to peruse. assuming you can wait that long.
 

472viper

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Oct 17, 2019
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Sioux Falls SD
No problem, and pics would be great. I live in South Dakota, we have two seasons, driving and wrenching. Wrenching season can start as early as October, but it's driving season now so the conversion will wait a bit. But I can be gathering parts. I think I found a source for a distribution block that has the brake light switch in it. That would make it so simple !
 

rbohm

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Apr 12, 2002
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No problem, and pics would be great. I live in South Dakota, we have two seasons, driving and wrenching. Wrenching season can start as early as October, but it's driving season now so the conversion will wait a bit. But I can be gathering parts. I think I found a source for a distribution block that has the brake light switch in it. That would make it so simple !

the ford distribution blocks do not have the brake light switch in them, they have a brake warning switch, that lights up when one side has a leak and loses pressure.
 

rbohm

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Apr 12, 2002
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ok i finally got up the energy to get out and take a picture of my conversion set up, here it is;

DSCF0002.JPG


the brake light switch is in the rear line. the front coupler goes to the factory distribution block for the front wheels, and there is a plug in the distribution block where the rear line went in. that is now connected to the "T" fitting, and down where the line was disconnected from the distribution block there is a similar coupler to the one you see in the picture.

when i get around to pulling the motor for a rebuild, i will change the system by adding a later model distribution block so i can install a brake warning light, though i will keep the "T" fitting so i can keep the brake light switch. but for now this setup works very nicely. of course at some point i will install disc brakes in the front and larger drums in the rear, or at least that is the plan.
 

472viper

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Oct 17, 2019
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Sioux Falls SD
Hey I really appreciate the pic and the explaination. But couldn't you just find a distribution block that has a port for the brake light switch ? leed brakes tells me they do make such an animal.
 

rbohm

SN Certified Technician
Apr 12, 2002
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i probably could have, but back then i was working in a national park, and dealing with small town parts stores, and i needed the car done quickly. so i found the parts i needed that worked, and did the job. today perhaps i would have done things differently, though perhaps the "T" fitting would still have been used, but with a factory distribution block.this was done in about 2006 as i recall. heck i installed speed bleeders so i could bleed the system by myself.
 

rbohm

SN Certified Technician
Apr 12, 2002
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yep, it worked perfectly the first time. i even upgraded the wheel cylinders at the same time to the V8 mustang wheel cylinders for better braking. not a huge improvement but noticible none the less.