I have a 1940 40 Ford 2 door sedan, that was started by it's former owner. I have taken the car back down to the rolling chassis to get things correct (like the frame being almost cut in half when the new floor pans were installed, and then just left as is. Always go under the car BEFORE you buy it.). It has a Mustang II front end with disc brakes and a newer Ford rear with drums. Here is a picture of the booster/master cylinder that's on it. I am going to put new lines it as the current ones look like cr-p. 1. Do I need to install a proportioning valve for the rear brakes? 2. Do I need residual pressure valves? 3. Where in the system should I install the brake light switch? 4. Any suggestions for an emergency brake setup?
you need residuals for front and back plus an adjutable proportioning valve from summit. put the brake light switch on any line coming out of the master using a t fitting and mount it about a foot from source on the frame rail..
just curious, but is there anything wrong with using a gm style proportion/combination valve and if so....are the residual valves necessary. we've always ran them this way with no troubles, but if its not recommended or not as effective i'd like to know. my current setup is similar to capt. mikes with the addition of the combination valve. (front mII setup and rear drum).
You need residual valves if the lines are higher anywhere than the Master Cyl. so the fluid doesn't run back. Given your's is frame mounted, I would put them in-----as close to the MC as possible. With disc/drum you also should use a proportioning valve. You can put a pressure activated valve in the brake line or use a mechanical lever activator which will work off the brake pedal. Opinions vary as to which is better. I've used both kinds without a problem. If you use a mechanical lever, be sure you have a return spring on the brake pedal arm to bring it back all the way to original positiion so the light will shut off.
Residual pressure valves for the disc portion should be 2 psi......for drums 10 psi.....I would not worry about a proportioning valve initially......get the car running and driving and test the brakes, looking for premature lockup , usually the rears, if it occurs. If the fronts lock first, that's considered desirable. rear lockup will cause skidding sideways. However, the only reason to use a pro valve is in the event of rear lockup PRIOR to front lockup. I have built a couple of vehicles that did not exhibit that trait. It (premature lockup) has to do with several factors, size of master cylinder bore vs wheel cylinder/caliper bore size, lining/pad friction, vehicle weight distribution, tire diameter front to rear etc. Some of the 'conventional wisdom' is based on physics.......some on experience and some on hearsay. Ray
I dunno if its just the camera angle, but the booster/MC look really close to that hot exhaust. Are you dead set against a firewall MC? You get rid of the residual valves that way, it's easier to add fluid, plus, more importantly to me, you could run a bigger booster. That one looks like a single diaphragm 7 or 8" generic. My dual dia 8" from piratejack was a real POS with poor boost and frighteningly the power booster rod snapped while I was bleeding the brakes. I got a rebuild from autozone that's 100% better, with a real metal booster rod. oh FWIW I added a lever actuated brakelight switch, thinking it would be easier than plumbing in a pressure switch. It turned out to be a real PITA, probably due to universal brake pedal that I used. I may switch back to a pressure swwitch, I think it'll be more reliable. Good advice to drive the car before getting an adjustable prop valve. I put one in and just leave it full open, I know someone else that does the same.
First off manyolcars is right, we don't do streetrods here. Nor ratrods. But a nicely done traditional styled car is more than welcome with some modern amenities. That said. With the booster/master under the floor you do need residual pressure valves for sure. I would try it without the proportioning valve initially just to see. But as in all cases a little more info goes a long way.
You've got enough answers to the brake question, i'll leave it up to you to sort out the wheat from the chaff, for emergancy brakes i have used the lokar setup with very good results on a number of projects, most recent of which is a '67 International Travelall. If the emg brake can hold that monster, it'll hold anything. Good luck, oj
Wow the PC Police are out in force today. The guy is a FNG and used the word street rod in the title - BFD. This is a legitimate question to post on this site and you guys are all over him like a pack of wolves. What's the matter with you guys? It's not as if he posted a question about "traditional air bags" or other such inappropriate technical content. Living proof that if you put more than two human beings together you have divisiveness.
if you want to use an inline pressure switch you need a TEE with inverted flare two ways for the brake line and a 1/8" NPT port to screw the switch into.......Weatherhead part # 652X3 for 3/16" lines. for 1/4" lines 652X4 for emergency brake , i see you have a later ford rear... if it has drum brakes it should have emergency brakes built in. you can use Lokar universal cables to connect them to the original `40 ford front cable. you will need to fab some simple brackets. then use can use the stock under dash handle. i've done that on several 40's and it worked out nice
I have installed adjustable proportioning valves in most cars I have built for customers ONLY so I can say all was done to the brakes. I have yet to see any difference when valve is open or closed or in between.............
Exactly what is the difference between a street rod and a traditional hot rod? I certainly don't want to talk about or seek any help about my car here if it doesn't fit the mold.
When it comes to brakes there shouldn't be anything. Although you'll get some who will argue that front drums are the end-all because discs are ugly...whatever. Some are just overly sensitive to the words street rod or rat rod, so don't use them.
If you use disc brakes in front, and want an inline pressure swith, you will need a LOW PRESSURE brake switch. With disc brakes, you won't develop enough line pressure to activate a regular in line switch. After a lot of searching, I finally found a well priced low pressure switch from painless. (some think they are made of gold) I have had my xxxxxt xod for 20 years abd have never needed a porpotioniong valve.
I got residual valves and proportioning valve from speedway. They both take 1/8 pipe. But came with reducers to use 3/16 brake line. Can I just use brass 1/8 pipe between the two Sent from my iPhone using H.A.M.B.
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