[FC] Rampside Rear Springs

[Dale Dewald]

Hello Folks,

 From what I can ascertain [using my Oct 1, 1964 P&A Catalog] GM 
manufactured three different FC rear springs:

61-62 All FC (1/2"orange, 1/2"lime full length) .............. # 3798434
63-64 FC w/ side ramp (1/2"yellow, 1/2"purple stripe) ... # 3829556
63-65 FC exc. side ramp ........................................... # 3848586

I have a pair of # 3829556 that I removed from one of my parts Greenbriers. 
They were obviously installed as replacements to that vehicle shortly 
before it was retired. The springs still had their paper parts tags and 
were almost new looking as compared to the rest of the vehicle (a Michigan 
rust bucket). I measured these to have: 6-3/4 coils of 49/64" dia wire and 
an overall free length of 11.5"

I do not have dimension data for the other two spring numbers. The original 
# 3848586 springs on our Greenbrier were deformed at the bottom as if 
apparently heated and allowed to sag to reduce ride height. I replaced them 
because one was developing a fatigue crack near the deformation.

I had the # 3892556 springs blasted and painted, then installed on our '65 
Greenbrier for a while. They are very stiff. When unloaded, our Greenbrier 
sat with about 1.5 deg positive camber, but only compressed to about 1/2 
deg negative with a full [over] load. I have since replaced them with 
Clark's C1661RP which sit with 1 deg positive camber empty, but compress to 
1-2 deg negative with a full load.

I have the pair of # 3829556 springs for sale for $75 or best offer.

I would really like to come up with some designs for progressive rate rear 
springs for our FC's. It would help if I could get measurements of original 
# 3798434 and # 3848586 springs.

Dale Dewald
Hancock, MI

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At 17:25 3/26/2012 -0500, David wrote:
Bill,

Not much wrong with my old springs, its just that the rear sits a bit low
in relation to the front. I thought that the replacements would make it
"level". The rate itself seems perfect with the originals. I did not
imagine that the replacements would be so: 1. stiff, 2. tall.