71 C-body front stub frame to body bushings

[JeeperBillMI]

I was looking at an old thread while researching body mount bushings for a Plymouth wagon. Rather than resurrect an ancient thread I am starting this new one. I have other brand X cars in the stable and my 69 Camaro Convertible has a front subframe with rubber bushing mounts. I am not sure if the bolt size will work with those bushings but the GM mounts are supporting the whole body on 4 molded bushings to the sub-frame. You would have to buy 2 additional bushings if they match up size and function wise. Another alternative would be to look at body to frame mounts for older Dodge Durango with a frame and or Dodge Rams. I don’t think the Ram or Durango bushings would be as good because the body is just resting on a frame as opposed to being part of the suspension technically on the C-body. The modern Mopar bushings would also be metric likely 14mm and that could also cause clearance problems for the original sized bolts. Just my suggestions and hopefully this will help somebody. At least it may save some regulation hockey pucks from being slaughtered.

 

[Big_John]

I always have figured that hockey pucks would crumble with age. BTW, a hockey puck is 90-91 Durometer on the A scale (at freezing). Soft urethane mounts are 70A, medium are 88A and hard mounts are 95A.

 

[CBODY67]

In the worldd of GM body mounts, there are mating uppers and lowers. One or BOTH of them have an inner sleeve surrounded by the rubber. So they will not compress too much or "pooch out" too much when the inner bolt it torqued to specs.

On my '77 Camaro, I found some oxide-coated Grade 8 body bolts in the GM Standard Parts catalog. They seemed to more-securely hold things together. In some climates, the body bolts will "hour glass" with age, weakening them in the process, so new and stronger bolts than OEM are a good upgrade, by observation.

By comparison, the Chrysler stub frame "insulators" (on my '70 Monaco) are larger and thicker than those on my '77 Camaro. A MAIN concern is to mimic the standard, stock thickness of the upper body mount, so maintain the correct clearance of the SF to the underbody. As long as that thickness is maintained, the durometer reading can be of your choosing. The lower mount can continue the spacing situation, too, but can be less important as to how thick it is, as long as it correctly indexes and maintains the diameter of the hole in the SF to ensure everything is centered as it should be and will NOT move around.

While more-solid body mounts can provide a stronger "feel" of things, they can/will also transmit more road forces into the floor pan area. The rubber is strong/thick enough to absorb many of these forces and NVH factors as some of the forces can be transmitted into the floor pan and areas that were not designed to deal with them. THAT can cause some issues as the car ages, possibly. Resulting in sheet metal cracks in small areas as time progresses. Of course, this can depend upon how smooth the roads encountered might be and how long of a time is involved.

Just some thoughts and observations. Whatever works!
CBODY67

 

[JeeperBillMI]

In the worldd of GM body mounts, there are mating uppers and lowers. One or BOTH of them have an inner sleeve surrounded by the rubber. So they will not compress too much or "pooch out" too much when the inner bolt it torqued to specs.

On my '77 Camaro, I found some oxide-coated Grade 8 body bolts in the GM Standard Parts catalog. They seemed to more-securely hold things together. In some climates, the body bolts will "hour glass" with age, weakening them in the process, so new and stronger bolts than OEM are a good upgrade, by observation.

By comparison, the Chrysler stub frame "insulators" (on my '70 Monaco) are larger and thicker than those on my '77 Camaro. A MAIN concern is to mimic the standard, stock thickness of the upper body mount, so maintain the correct clearance of the SF to the underbody. As long as that thickness is maintained, the durometer reading can be of your choosing. The lower mount can continue the spacing situation, too, but can be less important as to how thick it is, as long as it correctly indexes and maintains the diameter of the hole in the SF to ensure everything is centered as it should be and will NOT move around.

While more-solid body mounts can provide a stronger "feel" of things, they can/will also transmit more road forces into the floor pan area. The rubber is strong/thick enough to absorb many of these forces and NVH factors as some of the forces can be transmitted into the floor pan and areas that were not designed to deal with them. THAT can cause some issues as the car ages, possibly. Resulting in sheet metal cracks in small areas as time progresses. Of course, this can depend upon how smooth the roads encountered might be and how long of a time is involved.

Just some thoughts and observations. Whatever works!
CBODY67

The Fury mounts do look thicker and larger. Thanks for the input.