C1 front control arm "droop"

[Al C.]

I measured 3-1/2 inches difference in the height of the front lower arm pivots ( heights above ground, inner minus outer, at the front bolt centers). I can't find a spec on this measure of lower control arm angle. Could some other 58-62 owners with standard suspension please measure this (height difference) on their car? Thanks.
... Al '58 #378 245hp NCRS SACC

[William C.]

Re: C1 front control arm "droop"

Al, the only dimension referenced is the height from the center of the front of the inner a arm pivot to the ground. With a 6.70 tire it should be 11 inches +/- 1/2 for std susp or 8 3/4 +/- 1/2 for HD suspension. If not using 6.70, adjust by 1/2 the difference in tire diameter

[Al C.]

Re: C1 front control arm "droop"

Bill - Thanks, I have that but that doesn't help me right now cuz' I'm on jackstands under the control arms. I need to know how much the lower arm should slope from inner to outer pivot as measured at the front, to verify my spring installation.
I hope someone will brave the cold with their tape measure.
... Al '58 #378 245hp

[Brian W.]

Re: C1 front control arm "droop"

Al:
My '62 measures approx. 1" slope. This is sitting on the wheels complete car and engine. My '57 measures approx. 3 1/4" sitting on the wheels, no motor, no body.
Regards
Brian

[Mike G.]

Re: C1 front control arm "droop"

Is the lower control arm the same as the lower A-arm? If so, on my chassis, which includes engine and trans, but no body or radiator, I get a 4" height difference, measured at the forward grease fittings.

My suspension was rebuilt, I don't know by whom, so I can't vouch for "correctness," but I know the place was a quality shop. Since the body is off the frame, I can snap some pictures and email them if you want.

[Roy Braatz]

Re: C1 front control arm "droop"

Al! Are you asking about the steering Idler third arm? Is so,there are three different idler arms 53-55 one ,56-57 one, another 58 to 62.The thickness of the rear flange is the change.

[Al C.]

Re: C1 front control arm "droop"

Thanks guys,
Brian's 62 complete car is the data I need (1", darn it). I'm afraid that the 3+1/2" slope of my lower control arm (= lower a-arm) means that somehow my coil spring is not properly seated up in the spring tower, resulting in incorrect a-arm angle.
So I have to disassemble (again) and try to correct this. Funny thing, it's the same on both sides, and it seemed that everything went together fairly smoothly.
The original symptom was too steep an angle (about 45 deg) where stabilizer bar meets top of the link bolt. Then I realized the upper a-arm is sitting on the upper bumper, which can't be right.
I'd love to hear from another complete 58-62 for verification before I do it. (again)..
... Al '58 #378 245hp NCRS SACC

[Steve Junkersfeld]

Re: C1 front control arm "droop"

Al, On my 56, the top of the coil spring is shaped to be flat and set in the top of the tower. The bottom of the coil is a normal shaped coil and the end of the spring rests in a recess in the lower control arm. You indicated that you were concerned about the spring not being set in the top of the tower - I think it is more likely that the bottom of the spring would not be set correctly in the lower control arm. I can't help you with measurements since the body is off of my 56. Good Luck, Steve

[John M.]

Re: C1 front control arm "droop"

Al,
I don't know how the spring could not be seated in the tower right, since the spring is ground flat on that end. The lower end is position sensitive, but you can use an inspection mirror and a flashlight to assure that the spring end is in the pocket. The upper end could be sitting on the little lip around the cup, but you should be able to pop it in with a large screwdriver without pulling it back apart.

Regards, John McGraw

[Al C.]

Re: C1 front control arm "droop"

I verified that the lower end of the spring is seated nicely, right where it should be. I couldn't convince myself that I could see or feel up into the spring tower, so I pulled the shock. The top appears seated properly. So, not knowing what to believe, I put the safety all-thread in place, decoupled the lower outer bushing, and (jack) decompressed the spring. With the coils spread out more, I could see that the top of the spring is right where it should be!! This work done the right side; left side still together.
To get from 3+1/2 inches to 1 inch at the outer (and wheel) should take about 500 pounds up front, according to the spring rate given in an old restorer article. No way that's going to happen.
I've reviewed and re-reviewed the setup; there just isn't any way to assemble it incorrectly (?).
I'm mystified - maybe these springs are too strong? The overall length appears about right at 14" free.
... Al '58 #378 245hp NCRS SACC

[Joe Pennington]

Re: C1 front control arm "droop"

On my 56, I measured 1.5 inches with standard front springs. The car is up on a lift so I was trying to measure it with another car in my way, so I could be off by a 1/4 inch. Yes, I know heavy duty springs were not available in 56.

[Al C.]

Re: C1 front control arm "droop"

Joe -
Thanks for measuring - I'm believing that something like 1 to 2 inches makes sense; with my 3-1/2, the upper bumper is in compression. I'm trying to understand why this is happening.

[Joe Pennington]

Re: C1 front control arm "droop"

Al, I reread your post and you didn't mention is you are reusing the original springs or have installed replacement springs.

[Roy Braatz]

Re: C1 front control arm "droop"

I believe you have the wrong springs . measure the thickness of a coil and compair it with the old ones.That will tell!

[John M.]

Re: C1 front control arm "droop"

Al,
You indicated that you re-used the original springs, If is not the case then it is quite possible that you got the wrong ones! A friend of mine had tha same problem, he bought springs from one of the large Corvette vendors and had the springs topped against the bumpers when he drove it arround the block. I gave him a set off my 59 basket-case and he sent them back for credit.

Regards, John McGraw