How to mount early 30's GM Bodies - Specifically 1932 Pontiac Sport Coupe

[32Pontiac6]

I need help on how to mount the body of my 1932 Pontiac Sport Coupe.  The body bolts to the top of the frame at the firewall, and first door pillar.  There is mount that attaches to the side of the frame just rear of the back door pillar.  The rear mount is a metal bracket that bolts on the top of the frame.  Each mounting point had a pad that was approximately 3" x 2" by 1/8" thick.  My questions is what is used, specifically where the splash apron is installed.  I have some 1/8" think by 2" webbing material that I plan to use between the splash apron and frame.  I was also thinking of using another piece between the splash apron and body.  I don't know if this plan is correct.   Any help or pointing me to some reference that would describe the process would be quite helpful.

Thanks,

Rob

 

[Hubert_25-25]

Rob,

I am doing a frame off on a 1925 Buick Touring and this sounds very similar. My stack on top of the frame is like this.

1) 1/8" thick x 1 1/2" wide strips of a tar paper felt. Each strip is 1 to 1 1/2 foot long. They are only under the apron area to protect the apron and frame from touching each other. I may use a closed cell foam to replace this. Ford used tarred webbing material.

2) The sheet metal Apron

3) 1/4" thick Neoprene rubber pads (1 1/2" x 2 1/2" with a 5/8 hole in the middle) . I consider these the body mounts. They are held by nails to the underside of the sill. There are 14 of these on my car. The body bolts go thru these.

4) a single 1/4" thick wood shims under some but not all of the body attachment points. These are nailed to the sill of the wood frame.

5) The Body itself. This is a wood frame with sheet metal panels.

The apron stops before the rear wheel, so there is no 1/8 tar paper past this point.

This photo is of the front attachment point of a 1925 Buick Opera coupe. Same stack as described, but no 1/4" wood shim. I think they just added those as needed.

Hugh Leidlein

Edited March 6, 2016 by gr8success (see edit history)

[32Pontiac6]

Hugh,

Thanks!  I was really surprised at the number of people who looked at my post but did not respond.  I was thinking that maybe this is a dumb question.  Your post is quite helpful.  After I posted I dug through all my old parts and pieces and did find something that looked like tar paper under one of the mounting points.  My plan is very similar to yours but I am going to use the fabric welting under the splash apron.  It seems to most closely match the fragments I found.  My body mounts at 8 points around the car.  From body down the best I can determine for the mounting points is: 1/4 or 1/8 inch wood strip attached to main sill, 1/4" + - rubber pad (the pad looks like diaphragm material with reinforcement inside) then the mounting point.  I am using diaphragm rubber to make these mounting pads.  I considered the neoprene material but it seems much softer than what I found the original pads to have and it does not have the reinforcement.  I am making some metal shims, if necessary, to square up the doors after the body is bolted down.  I will sandwich the shims with 1/16" diaphragm rubber or possibly neoprene if the diaphragm is too thick.  I was surprised at the number and size of the body bolts for your car.  My car has 8 mounting points with 7/16" carriage bolts.  

Thanks again for your help.  While I am sure my process does not match exactly what was done in the factory in 1932, it is close and will surely work.

Rob

[39BuickEight]

I find used truck tire flaps are perfect for making body mount pads. They are plentiful at any truck service shop, and usually free.

[Hubert_25-25]

Rob,
Ford used fabric welting and I agree with you that it is better than the tar paper.  The fabric welting should be a tarred welting in my opinion so it does not hold water. 
The 1/4" body mounts were solid rubber on my car. Being 90 years old they are now hard as a rock. I am sure at one time they were supple. I selected Neoprene because it has excellent resistance to gasoline / oil etc and I did not want the rubber to dissolve if oil of gas got on it. I think the body mount needs to perform a purpose, being to soften vibration to the body so there needs to be some thickness in the pad to be able to do this. I thought about diaphragm material which is cloth reinforced, but I don't think that the cloth reinforcing is necessary. Any thickness less than 1/4" on your old mounts may be over squeezed mounts. The mounts still have to be hard enough that they can be used to align body gaps as well. . The hole in my rubber pads is 5/8 but the bolts are 5/16 inch diameter. Zoro sells the rubber sheets in 1' X 1' squares or 2" strips. The squares are about $10. I cut 1 1/2" wide strips with a rug cutting curved blade hand tool. I used a 5/8 punch from a harbor freight hole punch set. I put a stack of oak, rubber, and the punch into a bench vise, and when I cranked on the vise it made a nice smooth hole and the wood protected the sharp punch end.
Best Regards. Hugh.

Edited March 14, 2016 by gr8success (see edit history)

[Hubert_25-25]

I think the reason for a lack of response could be lack of an audience. The pre war Buick forum has some great knowledge, and your car is a GM so you may try posts on that forum site. Hugh

[TerryB]

A lot of us read the posts but are unable to help as we may have no experience with that procedure. A few who are familiar will usually respond. I read them to hopefully gain some knowledge as I have never owned anything that old.

Terry

[Spinneyhill]

I agree with TerryB. I am here to learn and contribute on the odd occasion I can.

 

I have obtained some conveyor belt "rubber" with cloth reinforcement for this purpose when I need to do it. The reinforcing should stop the rubber expanding laterally when you compress it (Poisson's ratio effect).

[32Pontiac6]

Well, the job is done.  Thanks for you input, Hugh, and for the comments from others. 

 

I ended up with the cloth welting, then splash aprons, and then the diaphragm material on the 6 bolting points.  

 

Hugh - one thing about the tarpaper vs. welting.  Could it be that the material changed between the 20's and early 30's?  Trying to scrape material off my pads and frame seemed to indicate that there might have been a cloth type material. 

 

 

 

 

[Hubert_25-25]

Rob,

   Great job putting it back together.  The tar paper is not super durable.  Things may have changed with what is on your car since it is a few years newer than mine.  I am going to research the welting a bit further.  I have not put the aprons back on my car yet. 

 

Hugh

Edited March 14, 2016 by gr8success (see edit history)

[Mark Gregory]

My car had a 90 pound felt like tar paper used on my car by the aprons . There is a big difference between tar paper and 90 pound felt . You need a strong knife or scissors to cut it .

Good luck with the restoration that is hard work as I am in the mist of it myself .

[Hubert_25-25]

Mark, Thanks for the clarification.  Yes, it is thick with lots of felt fibers, unlike tar paper.    I did not know what to call it, or where to get a good substitute.   Hugh