The Stovebolt Site Forums The Shop Area Engine Shop 3/4 T rear onto a 1/2 T

hello - i would like to increase capacity on my 59 6 cyl fleetside 1/2T 4sp. compound.
could i just add a special heavier spring to my current set up (and if so what spring ought i get ?)
or
might it be better to replace the rear with a 3/4 T rear end with springs?
thanks
paul

Why do you want to increase the capacity? How do you plan to use the truck?

3/4 ton springs will fit your truck. I have the extra heavy duty 10 leaf springs (optional for 3/4 ton) in mine. Beware you'll still only have half ton brakes, though.

ed - thanks for the heads up about the brakes.
do you know what is the exact difference in the 3/4 T brakes is ?

if i go the 3/4 T route should i get the 3/4 T reseviour and other assembly off of the 3600 ?
currently the brakes are stock on my 1/2 T fleetside.
sounds like i just answered my own ? if the 3/4 brake stuff is beefier.
thanks
paul

You still haven't answered how you are going to use the truck.

My 1959 1/2 ton longbed gmc has a set of helper springs, or overload springs on it. It also has air shocks. You could increase load carrying capacity in those simple ways. There is also a load handeling air bag available that can help carry a load.

As stated above if you want to carry more weight, it is important to be able to stop more weight. A disc brake setup on the front will help. The rear only accounts for about 15% of the total braking.

In addition, if you only swapped the rear brakes to 3/4 ton, which would also require swapping the rear axle, you would end up with a brake system with poor porformance, as the front and rear balance will be upset.
As far as springs go, 3/4 ton springs were a factory option on the '55-'59 trucks. My '55 3200 has 3/4 ton springs on the rear.

hello bigbaddaddy-
thanks for replying.
just trying to think out my options.
i have had airbags and while they are a low cost easy option i have found they donot last long. steel lasts.
disc are in the future but not now.
i can obtain 3/4 t stuff relatively easy.
do you know if the 3/4 t brake system is beefier than the 1/2 t ?
as to what i will haul ! mostly non commercial stuff.
you know like home and recreational stuff.

paul

The 3/4 ton brakes are beefier/larger, but swapping them will require swapping the entire brake system. The master cylinder itself is the only common part. The rear brakes will require swapping the entire axle, fronts will require at least a spindle and bearing swap. The hard lines will also have to be changed out as 3/4 ton uses larger steel lines. You will also find that the rear gear ratio is not highway freindly at 4.56 (std) or 5.13 (opt). Plus the wheels and tires will have to swapped due to the different bolt pattern.

Paul - changing your truck to a 3/4T for hauling average "home and recreational stuff" is wasted effort, unless you're building the home and playground if a reasonable load has it draggin it's butt you need some new springs

I regularly haul up to a ton of apples in my long fleet 1/2T with original overloads and the short step carries well over 1/2T with just good original suspension - mind you that's not on highways and the steering does get a little light

Bill

sounds like i will look into adding a helper spring to the 1/2 T.
and focus now on optimizeing the stock brake system.
thanks for all the good advice.
paul

Good plan. Brake upgrades are much easier to come by for 1/2 tons than 3/4tons. Just saw an article about 13" front disks for a 60's 1/2T. 3/4ton it's roll your own!