Cab Mounts for a 1948

[cobraffr]

Even though I had my truck for about 3 years now (in pieces in the garage). I have started my build in earnest.

I am in the process of moving the body onto a new aftermarket frame and have hit a bit of a snag. Since my truck is a 1948 it has a mount in the center of the back of the cab and rubber bumpers on the frame rails near where the shackles would mount on later model trucks.

Is it easier to covert the 1948 cab to the later mounting system or to add a cross beam to my frame for the center mount on the cab?

I have included a diagram comparing the two mounting options. Until I fount this I was very confused why my truck did not look like any others I had seen.

Thanks for any ideas or comments,
Donny
Like to build page for 1948 Chevy Truck

[dwcsr]

I faced that same decision a little while back and decide to go with the center mount.

Adding the side mount requires the cab supports be welded in and then you have to get the shackles in the right spot on the cab and the frame. if its off by a 1/2" it can throw off the fender ,cab hood alignment. If you leave the center mount you add a brace and measure to the center and be done.

Make sure you check the front mounts they may be cracked and need welding.

[msaintg]

I had the same question when I built my '47, but since I was doing a frame swap, I just converted it to 4 point mounts (no center support, no rear shackles, just 4 solid mounts)

[whitedog76]

I've never seen the center mount setup with the bumpstops before. Very interesting. It reminds me of the air ride cab setup that was on my Kenworth years ago.

I know the whole point of both designs is to allow frame flex without tin-canning the cab. Honestly, I can't see how either are that effective, when you consider the front of the cab is bolted to the frame.

The late model GM trucks are using a hydraulic mount setup on them. I've looked at them and wondered if somehow the same design couldn't somehow be adapted to an earlier truck.

My solution/idea is to use hydraulic engine mounts in place of the rear mounts. A hydraulic mount from a Volvo 740, 940, or 960 looks to be perfect for the application. They have a built in limiting strap and can be replaced with a solid rubber unit if they don't work out.

I'm not for sure how effective the setup would be either, but certainly they would provide a certain amount of dampening and as a bonus they would help eliminate some road vibration and engine harmonics that are transmitted throught the cab.

Chris

[mr48chev]

I've pondered that a bit over the years and if your new frame is stiff enough that it doesn't twist when you go over something like a high entrance to a parking lot or driveway I don't see why four solid mounts won't work ok. I'd want them to have cushions between the cab and the mount and below the mount to allow some give so it will flex a little though.

One has to remember that when these trucks were built they were often used in the fields and other places that were pretty uneven and had to have a lot of flex that they may not need when we just drive them on the street and the only off road use they get is riding across the lawn at a park to a parking spot during a car show.


You would want to use appropriate plates on the bottom side of the cab floor to strengthen the area though. I think all that is really missing is the outer cab mount bracket. The 47/48 cabs have that wrap around inside the back panel inner panel that strengthens it for the center mount setup.

[Gippetto]

I am doing my 47 GMC with the center shackle. I retained the stock frame and rebushed the shackel and replaced the rear bumpers so I am OK there.
What I need is a picture of the center shackle sheet metal enclosure from inside the truck. Mine was cut out (butchered) with possibly a hatchet. There is not enough metal left to figure out what to fabricate to close the hole up. It lookes like, maybe, the missing cover may have been removeable.

I appreciate any help here.