The Stovebolt Site Forums The Shop Area General Truck Talk '46 1/2 ton Master Cylinder update options needed...

I'm curious to see if anyone here has updated a '46 1/2 ton master cylinder to a dual resovour system?

Idealy, what i'd like to use is an "off the shelf" Master Cylinder from another vehicle that can be bolted on with minor fabrication/modification.

My current master cylinder has the boot on the plunger dry rotted away, and i've tried everything to get the darn lid off, and it's rusted tight.. so i'm thinking a new MC is in my future.

Now if I could find a stock replacement dirt cheap, well, then i'd go that route.. but if i'm going to spend more than $30 on it, I might as well go the full monte and get something with a front and rear resovoir, right? Right.

i have a universal dual resovour master cylninder its a corvette style. brand new. i also have a 7" universal brake bosster email if interested.

Fumblin', there a brand new ones available for about $140.00. Not remans. I didn't see one in Napa online but it's a newer part with the last 18 months or so. The master is integral with the pedal mount to the tranny. If you had an AD, I'd say go for a Late '60's mustang dual res, but you don't. The re-engineering that needs to go into the swap may get to be as much or more (when you figure in a new tranny, motor, on and on.........) than just bolting a brand new master. With new lines, and a new master, how much driving are you going to do in the rain and salt.........should last you for as long as you own the truck, and then some. The original went for awhile.

Or you can take your chances! 4583114741

Fumblin46,

I have upgraded my 1940 1/2 ton to dual master cylinder. I don't think the actual master cylinder matters. I cut the back half of the original bracket off and made a new one. This is working for me.

I have a little of it described on my web site:
http://home.twcny.rr.com/schickling/1940Chevy/rebuild5.html

I have more pictures of the changes.

Bill Schickling

Fumblin,
if by the lid, you mean the screw on resevoir top, here is how I would remove it. Get the unit off the truck and use a propane torch to heat around the threads. When it gives a bit, let it cool and unscrew it. If the inside isn't pitted, you can just rebuild it with a kit.

I used what is basically a GM dual master cylinder from MP Brakes. The thing that I did was to order one with the line outlets on the opposite of a stock unit because when you mount the unit either on an altered master cylinder bracket or on a new bracket (I made a new one), the lines on a stock unit exit the master cylinder right up against the transmission. Yes, you can probably get them in there, but I figured it would be a whole bunch easier to bring them in on the left side of the master cylinder just as the stock ones enter the stock unit. So far, it looks like it is going to work fine.

Joe

bill the master cylinder does matter. the bore on the back of the master cylinder maters. there are many different types. probably end up needing a 1" bore. the larger the bore the less pedal needed to stop. the problem is if an 1.125" is used when you barly push on the pedal the car will lock up the brakes. you need to match up the bore on the master cylinder to the bore on the piston of the caliper. most common type is 1" bore master cylinder.

55belairtim,

Sorry, didn't mean to imply that the master cylinder didn't matter to the truck. I meant the master cylinder didn't matter to the bracket I made. It seamed pretty universal. It just has a 'U' cut out for the rod and 2 holes drilled for mounting the MC. Sorry if I caused any confusion.

Bill Schickling

thats ok i may have misread that. myself just did not want other people to just start going to junk yard and trying to make a master cylinder off of some car work and see someone get hurt doing it.
at least it is all clear now