The Stovebolt Site Forums The Parking Lot Big Bolts Air Brakes On '50 Chevy?

I've got a 1950 chevy 6400, and im really curious about getting air brakes on it. its got a timken double reduction 2 speed rear that i'd like to keep. I don't care as much about retaining the front axle, but if reasonable at all, keeping the original one would be my preference. i plan on a 3-53 DD, but that is not set in stone at all. any help is greatly appreciated. TIa.

Welcome to the Stovebolt

Chevrolet didn't have air brakes available until 1957, so you will be in uncharted territory. GMC had it back then, so maybe finding an early 50's GMC donor truck with air brakes would be the easiest way to do the conversion as you're going to need EVERYTHING...

Mike B

The 450 GMC had a wider tread than the 2 tons. Putting air brakes on your Timken rear would take a lot of machining. The brake spiders for hydraulic or air are welded to the axle housing. Anything can be done. but what you are planning is going to be difficult to find parts and then a lot of labor when you find parts. Finding a donor truck is really the only feasible way to go. Your rear ratios will be too slow for a 3-53. And you will need a heavier suspension in front to handle the extra weight of the Detroit. Unless you have lotsa time and lotsa money, I wouldn't recommend even attempting what you want to do.

how much weight does the original suspension support? would an OD brownie help with the ratios at all?

The 6400 is a 2 ton truck with a front axle rating of 4000 or 4500 lbs. at the ground. If you have the original specs for the truck it will spell out the GVWR, for example, mine is a 5700 with a 16,000 GVWR with 9.00-22.5 tires - it weighs 7000 lbs. empty so a payload of 9000 lbs. without exceeding manufacturer specs.

MRVaughan Keep your 50 find an air brake GMC like you want or maybe trade for one,the sound will be worth it !!!

see, i got an absolutely incredible deal on this truck, and know the family that has owned it most of it's life, so i'd really like to keep it, and buying another truck would probably be a lot more expensive, and the female of the household would be quite against ANOTHER truck, im sure. i think modifying this one will be my best bet, because with the brakes it has in the condition they are in, it won't hardly be usable for my purposes (hauling cars, and whatever gravel/rock/dirt i need to). i do understand that a larger truck that's better equipped may be better, but i just so happen to have the fortune to know a few people that are willing to sell me some parts (motors, transmissions, ETC) at very reasonable prices, so i think i'd rather do that. i do understand that what i wish to do here is not entirely the most practical thing i could be doing, but i would rather get advice on how to do it, rather than why NOT to do it. i do understand and respect the knowledge and experience of all of you, and i understand that you do all make good points. but i have a somewhat specific way i'd like to have this rig built.

You are going to need to do something about your diff. ratio. The gears in your existing two speed will be slow and slower. You could get a modern close ratio trans.(required with a DD) get an updated disc brake rear axle, 10 on 7.25” bolt pattern would work, get a GMC two ton front axle to fit under your front end, find spindle and hubs, power steering and hydro boost from a GMC P-3500HD with 10 on 7.25” bolt pattern. That will keep you busy this summer, by then you will have your serviceable truck that looks original, but has modern, reliable innards with your 3-53.

Ed

Mr. Vaughan I see your situation there,lately have been seeing all kinds of Detroit 3-53's in GM AD and Task Force trucks. Even saww a 3-53 in a 70 roadrunner (who does that) ?? Anyway never can tell what is out there,forge into your project...I do !! I am the only bolter who runs an advanced design truck on propane (have 7) all liquid burners.

with all due respect, i would rather not go that route. i'd like to convert to a 10x11.25 (big rig) pattern, and air brakes at the same time. i don't necessarily want it looking stock, as much as i want it to have the capability to pull a lot. i have begun questioning whether the 3-53 is the best motor to go with, as it seems a bit underpowered for my goals. the only reason i considered it in the first place was because i could get one cheap. but i think now a v6 detroit or something similar may be better. i don't know what model exactly, but something like an eaton 5 speed would be a good tranny, backed up by a 4 spd auxiliary spicer. that or the existing sm420 with the same aux box, just because of, again, what i can get my grubby little hands on easily. that rear axle is something i'd like to keep, just because of how interesting it is, as well as it having low enough gears to pull a mountain off of its base. i want to be able to get going HEAVY.

A 3-53 wouldn't give you a whole lot of power than what you have. I have a few air brake axles with two speed rears, but they are very rare. Your chances of finding one are pretty slim. Something like a 12 valve Cummins might work. Single speed rears are everywhere and go for scrap iron price. I still have a lot of junk from when I was a licensed salvage dealer and I still have dozen trucks in my fleet that were built from salvage. The components you are talking about like a 5 speed Eaton and a 4 speed auxiliary would cost a whole lot than you probably paid for your truck in the first place.

https://photos.app.goo.gl/1BkcJZs7egKdn9W19

The SM-420 is rated at 420 foot pounds of torque, it might be to light for your needs.

Mike B

It will be a tight fit to get a Detroit Diesel 6V-53 in your engine compartment, even without an I’cooler. I think it might be best to put the 3-53 in there and enjoy that.

Ed