48-54 rear cab mounts - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BarnFind · 11-15-2012, 08:27 PM

Just getting my feet wet on this one. Im in the mock up stage and I have realized my frame is missing the rear cab mounts. I see two of my choices are a solid bracket, similar shape as the running board brackets, or the shackle type. Which is the better way to go? Sean

Coryd501 · 11-16-2012, 12:29 AM

I prefer the shackles
Posted via Mobile Device

BarnFind · 11-16-2012, 10:58 AM

Do the shackles actually allow the cab to move? I bought a new cab mount kit and Im not sure what the 8 rubber grommets are for. Im a mess !!

mr48chev · 11-16-2012, 01:11 PM

If you have an actual 47 or 48 cab it is designed to use the center mount on the rear. Those cabs have a reinforcement panel running around inside the back panel. It isn't a solid mount but actually uses bushings like the side mount but is designed as a three point mount. Those cabs won't have the weld nuts in the floor brace for the shackle mounts. the three point mount actually allows for more cab movement.

There is no reason you couldn't run the shackle mounts on that cab if you reinforce the places where the shackle mounts to and drill the holes in the 47/48 frame for the shackles to bolt to.
The original shackle mount holes are in the middle of the support bracket.

The 47/48 trucks will have a brace that runs all the way across as my drawing shows.

I can't find the photo I had showing the holes in the frame for the cab mount but they aren't the two holes in the raised section. They are the two staggered holes that are close to that raised section if they are there.

If you did a frame swap or have boxed the frame and put a stiff X-member in it you could use some biscuit type mounts and drop a bolt down through them on each side but I'm not sure I'd do that on a stock frame.

BarnFind · 11-16-2012, 01:27 PM

Hey MrChevy, thanks for the information! I actually have a 52 chevy frame and a 54 gmc cab. I just set the cab on so I could mock up the steering and I discovered the rear cab mounts are missing

mknittle · 11-17-2012, 11:14 AM

Quote:

Originally Posted by BarnFind

Do the shackles actually allow the cab to move? I bought a new cab mount kit and Im not sure what the 8 rubber grommets are for. Im a mess !!

yes they do as the frame flexes{ and they flex more than you might think}

When I was reworking my floor I left the shackles bolted up and was able to easily pick up each front corner About 5 inches inches per side a 2X4 at a timeper side.

mr48chev · 11-17-2012, 01:17 PM

I think some of the vendors have the whole unit or it shouldn't be too hard to get the piece that bolts to the cab, the shackles and the piece that bolts to the frame and a new set of bushings. When guys take these trucks apart they usually unbolt the bracket from the cab or frame and leave it on that part. Except for the guys who torch the shackle bars to get the cab off.

LMC shows the bushings http://www.lmctruck.com/icatalog/ca/full.aspx?Page=24 But they don't offer the metal pieces.

11-15-2012, 08:27 PM	#1
BarnFind Registered User Join Date: Oct 2010 Location: Santa Clarita, Ca. Posts: 80	48-54 rear cab mounts Just getting my feet wet on this one. Im in the mock up stage and I have realized my frame is missing the rear cab mounts. I see two of my choices are a solid bracket, similar shape as the running board brackets, or the shackle type. Which is the better way to go? Sean

11-16-2012, 12:29 AM	#2
Coryd501 Registered User Join Date: Feb 2012 Location: Conway AR Posts: 17	Re: 48-54 rear cab mounts I prefer the shackles Posted via Mobile Device

11-16-2012, 10:58 AM	#3
BarnFind Registered User Join Date: Oct 2010 Location: Santa Clarita, Ca. Posts: 80	Re: 48-54 rear cab mounts Do the shackles actually allow the cab to move? I bought a new cab mount kit and Im not sure what the 8 rubber grommets are for. Im a mess !!

11-16-2012, 01:11 PM	#4
mr48chev Registered User Join Date: Jul 2007 Location: Toppenish, WA Posts: 15,413	Re: 48-54 rear cab mounts If you have an actual 47 or 48 cab it is designed to use the center mount on the rear. Those cabs have a reinforcement panel running around inside the back panel. It isn't a solid mount but actually uses bushings like the side mount but is designed as a three point mount. Those cabs won't have the weld nuts in the floor brace for the shackle mounts. the three point mount actually allows for more cab movement. There is no reason you couldn't run the shackle mounts on that cab if you reinforce the places where the shackle mounts to and drill the holes in the 47/48 frame for the shackles to bolt to. The original shackle mount holes are in the middle of the support bracket. The 47/48 trucks will have a brace that runs all the way across as my drawing shows. I can't find the photo I had showing the holes in the frame for the cab mount but they aren't the two holes in the raised section. They are the two staggered holes that are close to that raised section if they are there. If you did a frame swap or have boxed the frame and put a stiff X-member in it you could use some biscuit type mounts and drop a bolt down through them on each side but I'm not sure I'd do that on a stock frame.

11-16-2012, 01:27 PM	#5
BarnFind Registered User Join Date: Oct 2010 Location: Santa Clarita, Ca. Posts: 80	Re: 48-54 rear cab mounts Hey MrChevy, thanks for the information! I actually have a 52 chevy frame and a 54 gmc cab. I just set the cab on so I could mock up the steering and I discovered the rear cab mounts are missing Attached Images

11-17-2012, 01:17 PM	#7
mr48chev Registered User Join Date: Jul 2007 Location: Toppenish, WA Posts: 15,413	Re: 48-54 rear cab mounts I think some of the vendors have the whole unit or it shouldn't be too hard to get the piece that bolts to the cab, the shackles and the piece that bolts to the frame and a new set of bushings. When guys take these trucks apart they usually unbolt the bracket from the cab or frame and leave it on that part. Except for the guys who torch the shackle bars to get the cab off. LMC shows the bushings http://www.lmctruck.com/icatalog/ca/full.aspx?Page=24 But they don't offer the metal pieces.



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