The Stovebolt Site Forums The Shop Area General Truck Talk Cab Mounting

I have a 54 advance design 3100 pickup and was wondering if anyone has eliminated the rear cab shackle mounts in favor of rigid mounts. It seems to me that this would help with door alignment and cab flex movement.

The point of the shackles is to provide flex. A solid mounted cab will bend some out of shape with the amount of frame flex the truck normally has.

The early 47-49-1/2 used a center type shackle very stiff semi- solid mount with frame bumpers and it was repaced by the shackles due to stress cracking in certain areas on the older trucks. I guess the point is your going backwards not forwards if you solid mount the cab.

Thanks for the input. I have rebuilt the mounts and they are installed but it was just a thought

I have a 48 and fortunately we don't have the roads as they had in 1948.

I don't have a problem with mounting the cab as original.

Article reference on the early trucks: http://auto.howstuffworks.com/1947-1955-chevrolet-trucks2.htm

The cab itself, which had previously been attached to the frame at three points via shackle bolts and rubber mounts, was now mounted at four points. The idea of the three-point system was to let the frame flex without affecting the cab. This worked well, but the single forward mount put too much stress on the front frame crossmember, so two smaller shackle mounts were set on the forward chassis rails instead. The cab was still unaffected by frame flexing thanks to the lessened tension of the shackle bolts.

Frame flexing had caused other problems as well. There'd been complaints, for example, that the 1947-1948 radiator support in the 3100s tended to twist and shake loose after many miles on rough roads. This caused splits in the radiator core, and cracks in front-end sheetmetal. For 1949, Chevrolet added X-bracing to the radiator support frame, reinforced the bottom channel, and mounted the entire assembly more rigidly.