I bought a 1971 F100 long bed with a 429 and C6 from a ’73 Merc about a year and a half ago, I live in Michigan and being smack-dab in the middle of the salt belt I like southwestern cars for their lack of serious rust issues. Luckily my blue ford is a Texas truck that migrated north with its Air Force owner a few years ago.

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I have a few things that have me stumped that I would like to fix.

The Steering is, for lack of a better term, soft, but it tracks straight. What I mean is, when you turn the steering wheel it responds but it’s not proportional.
I replaced the front suspension bushings and had the ball joints and kingpin checked at the same time, I was told that they were both fine which I believe because it doesn't wander.

Are the springs still good?
I know that the rear leaf spring packs have a C9** stamped on them, and the truck had a fifth wheel at some point in its existence, I've already dealt with some wiring issues, mostly due to lazy and haphazard work with splicing in trailer harnesses at the back and front of the bed. It has air shocks, which helps some, but it is still remarkably like navigating a boat in reverse when I drive on the highway.

Any help would be appreciated.

1971 F100 4X2, 429 & C6

 

First let me welcome you to the forum here at FTE.

I do not understand what you mean by "not proportional" & I'm totally confused by this post?
Usually I can parse out problems but you got me here. Can you clarify that a little more please?
You mean you have to turn Strg wheel more for one direction than another, as if your pitman
arm is installed wrong, out of sync' a turn or a turn & half or what do you mean?

It may simply be that you are overdue for an alignment.
If steering "seeks" it's center, or seems to "fall off center" or you need to chase it around curves
then pull it back because it does not want to "center up" or return to center
I'd say Toe-in & possibly caster are slightly off.
Some 5th wheelers set steering that way to handle excess forces on front suspension when loaded.

Also what are you calling Ball Joints, seeing as these trucks in 4X2 version do not have ball joints,
but use king pins in the ends of their modified, twin style, I Beam, front suspension set up, instead?

As for C9 Prefix it can be normal since C9 (1969) comes before D1 (1971) which is what your rig is.
If you had D2 or on up thru D9 you'd have replacement springs. So I'd venture C9 springs are OEM.
They probably are not worn unless truck's dragging it's tail, corners poorly or has other symptoms of
rear spring problems, such as wear, cracked leaves, worn friction spots etc etc.

FBp

 

Sorry about the confusion, trying to think in the morning without coffee is not good.
What I mean by 'not proportional' is when, in the course of normal driving I have to make minor corrections in steerage it seems to take more steering wheel motion than I would normally anticipate. I think that you are right about the toe-in issue, the truck does not want to find its center again coming out of turns. But doesn't the suspension play into that also, with body lean affection suspension angle and therefore steering gometery?
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So, maybe general alignment issues for the front end. Not surprising, and it might explain the harmonic that I get around 35-45mph, not constant mind you, but with a cyclical intensity.

<o></o>As for the springs, I know that the ‘C’ prefix means the 1960’s, but really my problem is a lack of understanding as to the symptoms of an aged suspension. The spring packs themselves appear to be in good condition, no obvious cracks or breaks, just a general lack of lateral stability, hence the boating remark. I understand that the springs provide the bulk of the work for suspension and that the shocks are really dampers for the springs smoothing out the spring rate.

<o></o>The Hodgekiss suspension (2 springs, 2 shocks, no tie bars, or sway bars) seems to allow more lateral motion to its mounting direction than I am used to seeing in a vehicle. The shackles are not damaged of worn that I can see and I replaced the bushings when I bought the truck, so I am ruling out play there. Basically that leaves me with fatigued springs and tires, right?




Thanks
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