The Stovebolt Site Forums The Shop Area Engine Shop Use 1.5 ton parking brake system on 3/4 or 1/ ton

HI Im trying to find out if you can, or has any one used the hand brake system From a 1.5 ton 1950 BIG BOLT AD truck and used it on a 1/2 to 1 ton AD pickup. It seems like a much simpler system with no rear cables or linkage to deal with and I think its the same 4 speed transmition used on 1/2 10 1.5 ton 4 speed on the floor with granny gear,I think its called a sm420 ,or 320? The emergency brake system looks like a small brake drum with with a brake band that tightens when the brake handle is pulled,very clean and simple,hope fully someone has tried this and can help me with ideas on how to make this atempt Thank You Green 48

The SM420 was an option on the lighter trucks, however, the parking brake would only work on the 1 ton. The 1/2 and 3/4 tons use a torque tube/ partial torque tube driveshaft system, respectivley. And even at that, I'm not so sure that the yoke for the 1 1/2 ton trans would work with the 1 ton driveshaft, plus, the 4 speed 1 tons actually have that style park brake, only smaller. If you've converted to open driveline, and have a driveshaft made with the right U-joints, then yes, you could use it.

Actually, my two 48 1.5 tons have rear brake cables. My 2 ton has the driveshaft brake. It does hold the truck better, until you have to jack up one of the rear tires, then it doesn't hold a thing,
Scott

THANKS I forgot about the closed drive shaft the truck im trying to put the 1.5 ton parking brake in is a 1 ton with open drive shaft but has linkage and cables and I just liked the simpler version of the big bolts My truck has a 1958 235 6 cyl. with the sm420 so I guess the Trans. is interchangible just not sure if the brake parts are seems like some one has tried if not Ill see what i can do and post for others

My 52 1 ton has the transmission mounted parking brake, and it's great, one of the best parking brakes I've ever had. From what I can tell it was swapped in at some time, as the truck should have had rear axle drum parking brake arrangement.

My 48 2 ton had rear axle drum parking brakes..

So, back to the question, yes, you can use it on small trucks. The simplest swap is a 1 ton, should be a direct bolt it, may need a different front half driveshaft.
On a 3/4 ton you would have to resolve the half enclosed driveshaft issue, may be as simple as the 1 ton swap with a new/borrowed font half driveshaft.
On a 1/2 ton it's not so easy, because you have to do away with the enclosed driveshaft, which involves a rear axle swap, that usually leads to brake and MC upgrades...

Grigg

I'm with Scott, I want mine stationary when on jacks.

Something I should have mentioned, 1 tons with the delete option 3 speed (4 speed was std equipment on 1 tons) would use the parking brake in the rear.