I can e-mail you a general brake plumbing guide with each of the above situations addressed. There are diagrams of each design. It also has cutaway drawings of MC's and combo valves with full explanations of each. Last, there is an excellent trouble shooting guide cause/effect/solution. PM me your e-mail address if you would like one e-mailed to you. Dave
my 1950 Mercury has a front disk brake conversion and original drums on the back. I have a booster but it is not connected (vac problem). The Merc is a heavy car and you have to push the pedal hard, but once I got used to it, it's no big deal. Works fine.
I have disc at all four corners and no booster, works great! I have a equalizer valve. Peddle pressure is just right. Typical hot rod is light weight enough to not need a booster and maybe better off without one.
Braketech Solutions Disk kit up front on my'54. When I put it on, asked both my dad and my father in law if they thought needed booster. Both said no. Been on for 2 years; thousands of miles. Work great. They are a treat compared to original drums.
Big GM front discs with S10 rear drums, Speedway proportioning valve. 1" dual MC, Jeep hanging pedal, no booster. Good firm pedal, light to moderate effort. Works very well. As others stated, pedal ratio is key. Mine is almost 7:1 with the Jeep pedal.
It'll work fine; I converted my 72 F100 to front disc, (used '77 F150 parts) no booster,...works great, after 25 years. 4TTRUK
This place never ceases to amaze me. This is the exact info I was looking for. Great thread! Posted using the Full Custom H.A.M.B. App!
32 Tudor with Pete & Jake chasis, Wilwood disks front, Curry 9" Ford with drums in back, conventional dual master cylinder with DOT 5 silicone fluid, residual valves 5# front, 10# rear, proportional valve. Works fine.
with a heavy brake pedal, I like to run a little heavier return springs on the carbs to keep the pedal feel balanced.
You make it sound easy Dave, but calculating brake systems confuses me. When I read the posts of those that do not have any combination or proportioning valves on a disc / drum setup I don't understand how that can work safely especially in a panic stop? I've heard anecdotally that some early OEM vehicles with disc / drums did not have valves? I'm thinking of using a combination valve in my 39 Plymouth pickup when I install front discs, but aren't combination valves calibrated for specific vehicle weight and other factors? I've been putting off my project only because I'm not sure what the best choice of components would be. I'm hoping to have a fairly good chance at doing this once and don't wish to die if a deer jumps in my path. Lols! Steve
I'm not a brake expert. But I do know that if you engage or (worse) lock up the rear brakes you will start to skid and / or spin out. It would be just like yanking on the e-brake. Any yaw or turn in the steering at the same you stomp on the pedal will undoubtedly cause the tail to p*** the front when the rears are locked up. Since most of the braking is done by the front wheels, the rears just need to follow along at a reduced pressure. I just had a friend nearly wreck his rod because he put a lot of bias towards the rear - because everyone had been telling him that engaging the rears first was the only way to go. Ask any motorcyclist what happens when you just stomp on the rear brake alone - you'll lay your scooter down - SkidsVille. I'd opt for an OEM style proportioner and not install a bias adjustment valve at all.
Use a 1" bore master and if the pedal is too hard make the pedal longer buy sistering another pedal and bar on to the original. I made the one on my old 64 Pontiac and extra two inches and wow what a difference!! This was a pendulum set up and I brought the pedal closer to the floor..
No booster on my 33 Chevy (disk up front, drum in rear) and no booster on my 46 Willys Jeep, had drums all around, now it has disks all around. You just have to press the brake pedal like you mean it if you need to come to a stop quickly. The only thing I don't like about not having a booster on my 33, it's the only automatic transmission that I own and I feel like I have to keep a decent amount of pressure on the brakes to keep the truck from moving. After a long drive through the mountains (where I'm using my brake alot) I get into town and while I'm at stop lights my leg gets tired. Sometimes I'll pop it into neutral just to give my leg a rest if I've been driving for a long time. It's funny, my left leg never gets tired of using a clutch, but my right leg gets tired using the brake on this truck, haha!
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