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What is the material used for front suspension shim?

3K views 12 replies 6 participants last post by  airbob01 
#1 ·
What is this material?

I am getting ready to install my rebuilt front suspension in my GT. When removing it,there was some sort of spacer between the cross member and the underbody support.
Does anyone know what this material is and what could be used as a suitable replacement?
 
#2 ·
The packers/insulators between the front suspension and the frame mounting points looks like high density compressed paper gasket material (red in colour). I have seen it in industrial applications so it is probably available from an Industrial supply house. Failing that you could use polyurethane sheet of the same composition as the "poly" suspension bushes.
Just don't use rubber sheeting as it will deteriorate and also be too soft, thus allowing the front suspension unit to move about.
 
#5 ·
Due to the fact my suspension is still sitting on the front porch, I grabbed my handy dandy calipers and did a quick check on the spacers thickness and it looks like a couple of pieces of Phenolic 3/16 X 1 5/8 X 6 1/8 will substitute very nicely with holes drilled in the correct places and of course the right diameter. HTH.
 
#6 ·
airbob01 said:
Thanks Jim,
I have been thinking of using phanolic as the spacer. Do you think this would be suitable?
I thought of that but it seems a bit hard and brittle to me. Would be OK as long as the surfaces were flat and smooth on the suspension and body.
Hard sheet plastic would have a bit of conformability it the mounting surfaces are not exactly flat.
 
#7 ·
Actually Jim, it looks like they are made out of Phenolic, or Micarta material that looks like it. But one is red and the other a light brown in their raw state. We used to use it as bearing supports and grease blocks on the prop shafts of my uncles full sized racing hydroplanes. With the mounting bolts going through the upper and lower sides of the frame and properly torqued, there "shouldn't" be any movement, so it says here in the fine print. ;)
 
#9 ·
jeff denton said:
What is it there for, anyway?
I too have speculated on "what for?" The best I can come up with is:

1) Insulating the front suspension unit from the frame to reduce the transmission of road noise/vibration to the body shell.

2) A handy, dandy method of adjusting caster by using inserts that are thicker one end than the other. But the inserts in mine are "square" being the same tickness front and rear. Has anyone else measured the thickness of the ones in their GTs ?
 
#10 ·
Doggone it, Jim, I was all set to sit down and have a nice easy session on the site, then your question on the spacers sent me to the garage for my handy dandy calipers, then to the front porch to measure the spacers. I measured them at the ends and mine are both the same thickness +/- .002". So I guess your first guess on the reason for their being there is correct, or at least plausible. :D
 
#12 ·
could it be as simple as a shim to lift the front end up to correct a ride hight discrepence
if its like Phenolic then its not going to reduce road noise its to hard!. if its for compliance then again its to hard!
just my thoughts:)
 
#13 ·
Thanks for the discussion. I removed the old suspension from my 71 GT and the spacers were good enough to reuse. They appear to be made of layers of pressed paper.
Got a new digital camera and took a shot of the rebuilt suspension before it is installed. Will install the shocks after I install the suspension.
Also made a couple of sleeves to adapt the KYB's so I could use the original size bolts. Will use washers to shim up the sides.
Thanks again for all the input.
Bob
 

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