The Stovebolt Site Forums The Shop Area Paint and Body Shop mounting cab to frame

Tomorrow I plan to mount my cab to my frame. My truck is a 1953 half ton. The cab is hanging by a chain hoist, above the frame. This all appears to be a very straight forward procedure. I just thought that I'd check in with this group in case you have any tips or hints that could help me, or cautions on things to avoid. Thanks

It is mostly straightforward. I've always attached the rear mounts first and then used a metal rod to line the front bolt holes up as needed. But ask 5 guys and you may get 5 different opinions, Mike.

I agree with Jon - rear mounts first, just recommend loosely installing the rear mounts to the underside of the cab first, then lower the cab down on the frame and make up the bolts to the frame. It's easier to align and get the bolts in that way. Good luck!

I place 3/4" pieces of wood on the frame near where the rear cab mounts are for the rear of the cab to lay on. 3/4" is close to what your gap there should be.
I then lower the cab slowly while fishing the front cab bolts through the hole in the bottom of the cab and the frame.
Once I have the front mount pads and shims in place, and my cab support-to-frame gap is correct, I tighten the bolts.
I then install the rear shackle mounts and make sure the cab-to-frame gaps are correct.
I do it in this order to stabilize the cab at the front mounts, because the rear shackles are wonky it the front of the cab is not in the right position and secure.

I know I am jumping in here with no value add to the conversation, but I cannot help but ask for some additional information from the group here... I am bad a reading the assembly manual, so... can anyone on this thread be specific about what the manual says about the gaps between frame and cab, both front and rear? I understand the 3/4" pieces of wood to approximate the rear gap... how about for the front of the cab? One more complication... I am putting the cab on an Art Morrison frame that does not require the rear shackles.. the cab is hard-bolted to the frame just as is done to the front of the cab. Any thoughts on what to be cautious about when mounting the rear of the cab in this way? My thoughts are that as long as we achieve the assembly manual gap recommendations on the rear, that is what matters, so add shims and pads as needed to achieve that gap. Also, I will have the option of playing with a completely new floor assembly individually from the cab (that is, I can mock up the floor by mounting it to the frame before I remove the old the old floor and weld in the new floor... does this make it easier to achieve the right gaps or will the whole world change when cab and floor are one unit? Thank you all in advance for helping a guy who is good on ideas but pitiful at bringing those ideas into reality.

The 47-54 FAM (Sect 1 Sheet 3.12 for all 3000 - 4000 - 6000 cabs) points at the shim between the floor and the cab mount shackle and say "USED TO MAINTAIN .76 +.06/-0 DIM BETWEEN FLOOR PANEL AND TOP OF FRAME"
For the front mounting point (Sect 1 Sheet 3.09) it calls out a dimension of "1.83 +.06/-0 TOP OF FRAME TO BOTTOM OF FLOOR PANEL 3000-4000-6000)"

That difference is interesting as the cab welding checking dimensions (Section 1, Sheet 1.07) indicates top of floor at 11.88 and top of frame at 10 above the reference line. That indicates that the floor is parallel with the top of the frame, but the rear shackle mounting dimension would have the rear lower than the front by over an inch.

Anyway, a rigid mount should maintain the same dimensions, assuming the frame configuration is the same as a stock frame.

If you have a different frame as long as the frame rails are in the same area as originals why not consider to use the original rear mounts they look to be decent and are cheap to replace the rubber

I am most fortunate to benefit from all of your advice and experience... Thanks

One thing to watch for...sorry not to have thought of this previously, but it can always be adjusted if need be. The pads you get today for the front of the cab are not the same as original. Big surprise, eh? They may look like the right height, but when used, they compress more. This wouldn't be a problem, because they more or less compress equally, however on the passenger side, your cab can start touching the frame and this will transmit a lot of noise you (a) don't want and (b) may even have trouble diagnosing. If you need to raise it a bit, you can go to a hardware or plumbing supply store and buy 1 foot (probably 1ft x 5 or 6 feet long) of shower pan liner. This is a PVC material and it won't compress much at all. Cut it into about 2" x 2" pieces put a hole in the center and use a jack/piece of wood to lift each side of the cab up where you can slide these in there. In fact if you have hammer punches (real common and today all made in Egypt, India, somewhere like that) you can make your own mounting pads using the special cement they use for this pvc shower liner and they'll be infinitely better than what you get today.

This is what I'm talking about. Get the 40 mil thickness: https://www.lowes.com/pd/Oatey-Shower-Pan-Gray-PVC-Shower-Pan-Liner/3127069

Yea that’ll work. I cut some for the front out of a heavy 18 wheeler mudflap works good but mine is a big bolt so the fenders are a little heavier. I also found rear shackle bushing for half of what I could find anywhere else, got em at the rubber feetwarehouse.com for.60 cents each.