The Stovebolt Site Forums The Shop Area The HiPo Shop Function of rear Cab Shackles

Does anyone have an explanation why the rear corners of the cab is mounted to the frame with shackles rather than bolted to it like the front of the cab? Is the intent for the shackles to allow the frame on the left and right side to flex up and down in the rear independent of one another? Like turning right over a curb, allowing the right frame to flex up while the left frame stayed straight. . . kind of alowing the cab to float on the frame. The reason I wanted to know is because if the frame is supposed to move up and down different on the left side than the right side then it would make sense that cross members in the rear should not be welded but rather bolted on the bottom side only. Welding a cross member will (it seems like) make the frame rigid.

Any thoughts about this? The reason I ask is because my frame rail on the right side is slightly higher in the back than the left side. I think this happened when we welded in the upper shock bracket to the left and right frame. If this is causing a problem then I'll cut the welds and attach the shock cross piece in a different way than welding it to the left and right frame.

Yes the frame does flex and if the cab was bolted solid to the frame then the cab would flex also! The cab has to remain rigid so that doors will fit. I wouldn't think some minor welding would twist your frame. A weak spring could be the cause. You may have to set the frame up on stands, get it off the suspension and then check/measure to see if its bent/twisted.

Thanks, Yakima...Washington, I assume. Anyway, when I bought this '54 truck it was in pieces. The guy didn't tell me the frame was off of a '53 (or earlier) truck. So, when I realized the hump in the rear frame over the axle housing was too high to accommodate the wood bed I ended up taking it to a fabrication shop and lowering the frame. I was there when they did the work and they basically kept the left and right frame rails in tact other than trimming off the top about 2 inches. Then they plated the top and boxed it off on the insides. Somewhere along the line, maybe prior to the work, the frame is about 1/2" higher on the passenger side in the rear than the drivers side. In looking at my numbers, with an investment of over 32,000 I don't need any imperfections. If I left it the way it is then I would have to shim the bed cross sills differently in order to get the bed to sit right. Dan

Frame is supported by suspension and springs. Height off ground is only part of the data needed. Are all tires the same and fully inflated? Wheel bearings O.K.? Springs intact? Shocks good? Brackets and mount points symmetrical?
1/4" here, 1/8" there...imperfections can "stack up" against you, and with the work done you described, there's a few extra places for things to get "off". I wonder what the new truck tolerance was for rear frame rail height in the early 50's...+/- 1/2"?

You are absolutely right. Good points. I have a lot to look at. Several new areas. new dropped leaf springs, altered upper rear frame, temporary "roller" tires, shot axle bearings (having new axles made to accommodate 5 lug - 4 1/2" spacing to match the front Mustang II). I appreciate your response.

Dan