[reborn55]

I have a 47 Chevy convertible with a single pot master cyliner and Midland booster. I want to convert to a dual master cylinder setup.I have front discs and rear drum. Is there a way to do it from under the car without a lot of frame modification (X-FRAME). It has what appears to be an aftermarket pedal/cylinder bracket. I would even consider using a dual cylinder non-power if it would work due to frame constraints (have less than 13 inches of vacuum anyway--cam). Have any of you done this before? Is there anyone that I could contact and try to do this modification. If not I will do the hanging pedal deal, which in this case would require moving fuse panel and modifying *****in dash. Any help would be appreciated. Thanks.

[40dodgeman]

mount under the floor and redo all the lines , using old lines can cause a lot of problems . there is a lot of info out get a good street rod magazine , don't jerry rig , do it right the first time

[reborn55]

Thanks--already have working setup, lines all plumbed real nice--just wanted to up grade to the dual master cylindre

[kleen56]

When you say underneath the car, I'm assuming your master cylinder will be on the frame instead of the firewall? You really need to go with the dual MC for safety reasons. With the single, your feeding both the front disc and rear drums, which is not real safe. The dual will cause you to require more space because they are longer. If your set on keeping disc and drum in the rear, you can use a MC from a 74 or so MonteCarlo. They are slightly smaller and may fit. They should bolt up to your booster as well. If your planning on going with disc and disc in the rear eventually, I'd go with the Corvette manual MC which you can use with or without a booster. With you having the MC on the frame you'll also need to install a 2lb to the front disc brakes and a 10lb residual valves to the drums. I'd also advise you to have an adjustable proportioning valve to adjust the pressure to the rear drum to avoid locking up.

[reborn55]

Originally Posted by kleen56

When you say underneath the car, I'm assuming your master cylinder will be on the frame instead of the firewall? You really need to go with the dual MC for safety reasons. With the single, your feeding both the front disc and rear drums, which is not real safe. The dual will cause you to require more space because they are longer. If your set on keeping disc and drum in the rear, you can use a MC from a 74 or so MonteCarlo. They are slightly smaller and may fit. They should bolt up to your booster as well. If your planning on going with disc and disc in the rear eventually, I'd go with the Corvette manual MC which you can use with or without a booster. With you having the MC on the frame you'll also need to install a 2lb to the front disc brakes and a 10lb residual valves to the drums. I'd also advise you to have an adjustable proportioning valve to adjust the pressure to the rear drum to avoid locking up.

Thanks again----problem I am having is room. I have the under floor single pot master cylinder hooked to aftermarket pedal and m/c adaptor. The booster is a remote Midland booster--not even sure how it works as fluid and vacuum are both integrated into the booster. I have the 10lb residual valve and wilwood adjustable proportioning valve to the rear.. Bought the car this way--my fault. With the x-frame there is no room for the S10 manual m/c of the Mustang type. I know there has got to be a smaller remote dual type that may fit without notching the frame. If not I will get the hanging pedal mount, but then I have to move the fuse panel as it is smack in the middle of where the pedal goes. great winter project. Thanks for input.

[powerrodsmike]

Can you retain your current pedal assembly and mount a dual booster and dual master cylinder towards the back of the car? I've had to install boosters on some cars where I made a long pushrod, and put the booster/MC mount 12-18" farther back.

Here is some pics of a setup I made for a 40 ford PU, that had a modified frame, (it was tubbed, and the rear frame rails went all the way to the front of the cab.),with no room for any master cylinder or booster towards the front. On this one, I had to make an assembly that put the brake pedal on one side of the frame and the actuating lever on the other. I built a plate with a bushing and attached the levers together with a shaft.

Later, mikey

[powerrodsmike]

Here is another one I made up for a 40 buick.

The frame rails were too close at the front of the x member, so it got moved back about 18"

I made the pedal, shaft and through-plate for that as well, using the stock pedal as a pattern.

Later, mikey

[reborn55]

All are very nice setups but I think I am still short on room. Did you do that on a finished car or one being built? very talented. Enclosed ar a few snaps of what I have. Been thinking of using one of the remote jobs the Master Power Brakes sell. Do you know if they will apply enought pressure to stop this big ol beast?
http://www.mpbrakes.com/products/pro...product_id=670

thanks again

[powerrodsmike]

Both of those setups I showed were done on previously finished and running cars for customers that needed more braking power.

I would think if you build a booster mount back behind the trans crossmember you would have lots of room.


If you want to use that 1" bore master with the remotes you should have enough stopping power, the pedal might be a little stiff, depending on your current pedal ratio. 6:1 is about right if you are using the metric GM calipers.

I would not go bigger on bore unless you use a booster.

Later, mikey

[reborn55]

Thanks Mikey--One of the reasons I was leaning toward that remote is that it might clear the angle of the xframe or close to it--could notch a little and using the exiting plumbed lines adding a residual valve for the front. Am running Mustang2 with stock rotors, calipers,etc. Booster is not necessry as only have about 12 inches of vacuum--running manual dics on my 55 and stop OK.
My fabricating and welding skills are still on a learning curve, so I tend to try to do things with the least amount of modification. So the hanging pedal with vacuum can may still be an option.
Another question--do you know how the Midland remote booster operates as I have one on the car and haven't been able to find any articles on it.

[powerrodsmike]

How does a Midland Ross brake remote booster work? Check this out:
http://www.freepatentsonline.com/287...47&stemming=on

Register on the freepatentsonline site and you can look at the whole text of the patent as well as pictures..

Later, mikey

[alittle1]

Reborn55,

Here is a brake setup for under the floor brakes that would be ideal setup for your use, put the MC back like Mikey suggested. See attached.