master cylinder

[Robert Thornton]

Does anyone have a good idea what duel master cylinder and fluid valve adj. for our trucks. I got my disk kit from Charlie and I really like the tough  look of kit and all parts will be easy to find. His instruction sheet would be hard to beat. even an old coot like me understand it  I am glad I got  this kit. It was a big day drove to Jackson tnn.  220 miles round trip picked up jeep rear end looks like new. And complete hub to hub. When I got home disc kit and new perches were in the mail.

[HanksB3B]

Lucky Guy..

 

Still struggling with my drum brakes. I think everyone should have Charlies Kit and a Cherokee rear axle. Discs take 20 minutes to change pads. My brake job is taking weeks and 45mph will still be my top speed.

 

It'll be awhile, 

 

Hank 

[pflaming]

Hank, now if you had taken my advice and stayed with the original patina, one you would be enjoying your brakes, two an easy 65 mph as you drive, and three have enough 'sauce' left over to drive up to the BBQ. "A WORD TO THE WISE".  I've got 10 days to get my truck ready, hope to make it.  

[Young Ed]

Hank, now if you had taken my advice and stayed with the original patina, one you would be enjoying your brakes, two an easy 65 mph as you drive, and three have enough 'sauce' left over to drive up to the BBQ. "A WORD TO THE WISE".  I've got 10 days to get my truck ready, hope to make it.  

 

How does paint or lack of paint get him a higher top speed(even though I believe he can go faster than 45 anyway) or better brakes??

[pflaming]

I stand corrected, they won't, he needs a 3:73 or better yet a 3:53 rear axle. Sorry about that. Disc brakes are optional, but VERY nice especially at 65 on the freeways. 

[Don Coatney]

Where can one find a 3.53/1 differential?

[Jeff Balazs]

You can retrofit a M/C from a Cherokee by making a simple mounting plate. Do a search you will see what several of us have done.

Jeff

[1940 Dodge VC]

Another way to solve the cruising speed problem is to use an overdrive.  I found a used Laycock overdrive from a Volvo, rebuilt it, and put it into the driveline.  Probably more work than switching rear ends.  On the other hand, the only modification was to the driveline, and the gas tank had to be moved over about an inch.  In the end, I retained the factory gear ratios.  Haven't tested it, yet.  I need to finish a few other modifications before starting it up.

[William Davey]

I installed Charlie's kit on the front, with stock rear drum brakes and a single stage master cylinder from NAPA.  No proportioning valves, no residual valves, but all new lines, hoses, rear cylinders and shoes.  So far it has been a trouble free and very powerful brake system.  My truck has 4:10 gears, so slowing down is aided by the engine braking, but the front discs really add a lot of braking power.  The truck is light enough in the rear end that even the stock rear brakes will lock up on dry pavement under very hard braking. 

[1940 Dodge VC]

I did some research on master cylinders--Jeff Balazs has a great thread on the Cherokee M/C.  Another option that looks promising is something out of an early 70's Dart.  That one comes with four mounting holes and a lot of clearance, plus it is quite inexpensive (around $20).  It would be a good candidate for Jeff's mod.  I also found a dual cylinder with three mounting holes and a 1" bore that came stock on non-ABS 1987-1988 Toyota Celicas.  It might bolt up without any modifications, though the lines will have to be modified.  It is a little pricey, though, ranging from $65 to $125 online.  The model numbers are Cardone 11-2240 or 13-2240, or Wagner MC122610.

[1940 Dodge VC]

Here are some comparison pictures of the Toyota and original master cylinders.

[1940 Dodge VC]

I don't know if anyone is following this thread anymore--want to give a brief update on the Toyota m/c and how my brake project turned out:

I installed disc brakes on the front and back of the truck (thanks, Rusty Hope!), and used the  Toyota master cylinder along with the appropriate pressure and metering valves. The m/c fit like it was made for the truck. No need for power brakes, this setup has plenty of power for stopping, with little effort on my part. So if you are looking for an m/c upgrade, I would strongly recommend the toyota version. 

The overdrive was well worth the effort, too. The cab is much quieter, my rpms are much lower, and I get the added benefit of easy upshifting/downshifting with the press of a button.

[Jeff Balazs]

Very cool conversion. Looks cleaner than the Grand Cherokee M/C I used. It was a tight fit and took some time to adjust. Works fine though. I have always been a fan of those Laycock OD units. Have had 3 of them over the years and they were faultless. Would love to see some pic's of this set up. These are the sorts of refinements that can really add to the driving experience.

Good on you and enjoy.

Jeff

[HotRodTractor]

Nice conversion! So - is that a single outlet, going into a 10psi residual pressure check valve, then into a proportioning valve and out to the respective ends of the vehicle? I need to get a master cylinder to make my swap to disc brakes yet, so this is perfect timing.

[1940 Dodge VC]

I'll post another shot of the setup here and explain it. Have to look under the hood  

[1940 Dodge VC]

The old single cylinder MC featured a three-eared mounting bracket that bolted directly to the bell housing. After a lot of research, I found a newer dual MC that bolts on with little modification. It was used in Toyota Celicas from the 1980’s. It cost $40 and has standard 3/16 flare SAE threads and an 15/16ths bore. The one I purchased was listed as a New Qualitee 6679750 Brake Master Cylinder 86 - 89 Celica incl. GTS w/o ABS. Last summer I worked on a 1994 Toyota Camry. From what I could see, the master cylinder is the same configuration as the Celica, so that might be another alternative.

Each of the mounting holes had to be elongated by about 1/8” to fit the existing pattern on the bell housing. I used a rat tail file to make the adjustment and it fit in perfectly. The push rod had to be shortened by about an inch and a half.

The 86-89 Celica master cylinder bore is 1”, while my old Dodge MC is 1 1/4” in diameter. The slightly smaller diameter provides more leverage, and the result is a pedal that feels and functions like a power brake. I mounted a proportioning valve and the residual valves. The MC is not much higher than the discs, so the residual valves help prevent back-filling of the MC. To prevent uncontrolled skids, a metering hold-off valve was added. Its purpose is to engage the rear brakes first.

[1940 Dodge VC]

Okay, I just checked on my setup. 2 lbs residual valves to front and back. Baby blue color from CCP.  The picture shows my original setup with disc brakes in front (2 lb residual) and drums in the back (10 lbs residual).  I updated the rear to discs and changed the residuals to match.

[1940 Dodge VC]

Two outlets, that is, two circuits. One for the front, the other for the back. Will try to get a better picture for you.

 

[1940 Dodge VC]

Jeff, I'll start a separate thread about the Laycock setup. I'm very happy with it. Yesterday my wife and I did a lot of touring around the countryside. It is so great to have the truck back on the road, and all of the upgrades are working very well. 

Here are a few pictures.

[Don Coatney]

I like the disc emergency brake.

[1940 Dodge VC]

Somehow I lost my post. Here it is with a little larger pictures:

[1940 Dodge VC]

Okay, Jeff, I started a new thread for the Laycock overdrives and wrote a fairly extensive description of what I did, plus I added a few pictures of the mounts. Thanks for asking about it.

[Prusakowski]

Do the wires coming out of the cap on the MC have any function in this adaptation?

 

[1940 Dodge VC]

The wires come with the MC and run to a float sensor within the MC tank. They provide a warning signal if the brake fluid level gets low. Very simple circuit. When the float goes down, the circuit is closed. You could run fused power to one of the wires, and from the other to an earthed (grounded) indicator light in the cab as a fluid level warning. I'm planning on doing that as a safety precaution.

 

[Jeff Balazs]

13 hours ago, 1940 Dodge VC said:

Okay, Jeff, I started a new thread for the Laycock overdrives and wrote a fairly extensive description of what I did, plus I added a few pictures of the mounts. Thanks for asking about it.

Yep saw it and I think you are one clever guy. I had thought about it a while back but you have proved it out. Good job!!! There is always more than one way to skin a cat. I love it. Have fun with it you deserve to.

Jeff