C1 Rear Spring Arch - Article?

[Tom D.]

Needing some help (again). I searched the archives for "arch" and "C1 spring" and didn't find a reference to an article we seem to remember.

Any reference to articles that would tell me the dimensions desired for the pcs. and the assembly of rear 1960 springs would be appreciated.

Thanks in advance
Tom D.

[John H.]

Re: C1 Rear Spring Arch - Article?

Tom -

Per the late Dale Pearman's notes, the C1 spring main leaf was 51" long from the center of the front eye to the center of the rear eye, and the correct unloaded arch (the drop from an imaginary line connecting the centers of the two eyes to the top of the leaf) is 5-1/2" to 5-3/4".

[Tom D.]

Re: C1 Rear Spring Arch - Article?

Thanks John!

Do you recall any articles?

Tom

[Ian G.]

Re: C1 Rear Spring Arch - Article?

hey John,

Would you measure the 51" with the springs mounted?
To get the unloaded spring measurement, just jack up the rear? or would you need to detach the axle?

thanks!

[Richard E.]

Re: C1 Rear Spring Arch - Article?

Hi Tom - Can't recall an article per se. But Dale's response on the DB covered all leaves, as well as paint requirements, etc. Look in the archives for his response "Rear Springs" on 8 November 2001. Hopefully it's still there. Cheers.....Dick

[Richard T.]

Re: C1 Rear Spring Arch - Article?

There is an old Restorer article that gives end to end dimensions for all leaves and slao explains how to cold work the leaves back into these dimensions. If I remember correctly it's from the early eighties. I'll check and see if I can find it. Rich

[Gary C.]

Re: C1 Rear Spring Arch - Article?

Restorer CD has several articles one about re-arching Summer 79. Gary....

[Keith R.]

Re: C1 Rear Spring Arch - Article?

Tom -

Per the late Dale Pearman's notes, the C1 spring main leaf was 51" long from the center of the front eye to the center of the rear eye, and the correct unloaded arch (the drop from an imaginary line connecting the centers of the two eyes to the top of the leaf) is 5-1/2" to 5-3/4".

I took the rear springs from my '60 into the Spring Shop today to have them disassembled and prepped for painting and reassembly. Before I took them in, I compared my measurements to the ones you quoted from Dale Pearman. Mine measure about 48 1/2" from eye center to eye center and the free or unloaded arch is over 6 1/2 inches on each. Is it possible that mine have been overarched and need corrective re-arching to bring them back in spec? See the attached photos of the measurements. Also included photos of how the body sat on the frame before disassembly.

[Stewart A.]

Re: C1 Rear Spring Arch - Article?

Be careful here because the 1960 cars sit up higher because of the rear sway bar. If you look at all 1960 cars they sit inches higher than a 58 59 at the rear. Richy you sent me a Corvette maintenance book a year ago that explains the ride hight is higher. Now I'm not sure if it's the spring or the sway bar that makes it higher. All I know it's higher. Personally I think the 1960 springs are set higher. I'll read the G.M. article when I get home and explain it better. I'm in the process of dropping mine a couple of inches because I don't like the car sitting up so high and seeing inside that ugly wheel well. In the photo you can see the original ride hight of the 57 see how the butt sits so low. The 58-59 were higher and the 60 was higher again. BILD0511.jpgCorvette_promo_foto_39.jpg

[Keith R.]

Re: C1 Rear Spring Arch - Article?

Tom -

Per the late Dale Pearman's notes, the C1 spring main leaf was 51" long from the center of the front eye to the center of the rear eye, and the correct unloaded arch (the drop from an imaginary line connecting the centers of the two eyes to the top of the leaf) is 5-1/2" to 5-3/4".

Be careful here because the 1960 cars sit up higher because of the rear sway bar. If you look at all 1960 cars they sit inches higher than a 58 59 at the rear. Richy you sent me a Corvette maintenance book a year ago that explains the ride hight is higher. Now I'm not sure if it's the spring or the sway bar that makes it higher. All I know it's higher. Personally I think the 1960 springs are set higher. I'll read the G.M. article when I get home and explain it better. I'm in the process of dropping mine a couple of inches because I don't like the car sitting up so high and seeing inside that ugly wheel well. In the photo you can see the original ride hight of the 57 see how the butt sits so low. The 58-59 were higher and the 60 was higher again. [ATTACH]17515[/ATTACH][ATTACH]17514[/ATTACH]

Thanks for the input Stewart. For the good of the group, here is the message I received from Mike at Eaton Springs in Detroit:

"In 1960 Corvette used only one rear spring. It's part number is 3751438, which can be found on the bottom leaf.

The spring measured 24 x 27 inches, free arch of 5-1/4 inches. The spring rate is 110 lbs and has a designed load of 575 lbs. The loaded height is 1/16 inch reverse.

The correct way to measure the length of a leaf spring is as though the spring is flat. Not by measuring eye to eye. The free arch is measured with the spring off the vehicle and through the centerline of the eyes. www.eatonsprings.com/measuring.htm explains all the details.

To answer your question, it is possible that the springs have been rearched over spec. However, the car would have sat high. We can bring the springs back to specs and how we do it is explained at www.eatonsprings.com/rearching.htm."

[John H.]

Re: C1 Rear Spring Arch - Article?

Be careful here because the 1960 cars sit up higher because of the rear sway bar. If you look at all 1960 cars they sit inches higher than a 58 59 at the rear. Richy you sent me a Corvette maintenance book a year ago that explains the ride hight is higher. Now I'm not sure if it's the spring or the sway bar that makes it higher. All I know it's higher. Personally I think the 1960 springs are set higher.

Stew -

All Corvettes from '57-'62 (except RPO H.D. cars) used exactly the same "438" rear spring, and the rear stabilizer bar had no effect on ride height with the car on a flat surface; the bar was only loaded in torsion under hard cornering or on an undulating road surface. Many 45-50-year-old springs have seen various attempts at "re-arching" (some better than others), and we see lots of ride height variations as a result of that.

[Stewart A.]

Re: C1 Rear Spring Arch - Article?

GM must have wrote a whole article wrong then. I have never seen a 58 59 sit at the same hight as a 60. I know you lived Corvettes all your life and run complete rings around me for tech stuff on Corvettes but the 60's sit higher. I'm positive. Here is a recent U.S car show I went to recently why is the 57 sitting so low at the butt with standard springs. Stewy BILD0551.jpg

[John H.]

Re: C1 Rear Spring Arch - Article?

Here is a recent U.S car show I went to recently why is the 57 sitting so low at the butt with standard springs. Stewy [ATTACH]17519[/ATTACH]

Probably just old, sagged springs that need to be re-arched properly (including heat-treat, annealing, and shot-peening, not just mechanically bent) - I see lots of them like that. My 57's sagged originals were re-arched correctly by Eaton Detroit Spring to the original print specs - photo below.

[Keith R.]

Re: C1 Rear Spring Arch - Article?

So John, it appears that with the correctly re-arched springs on your '57, you have an inch or two between the apex of the rear wheel opening and the top of the tire?

[Stewart A.]

Re: C1 Rear Spring Arch - Article?

Corvette V8 1955 - 1962 complete owners hand book.
In 1960, further development resulted in a truly '' dual - purpose machine. New front and rear stabilizer bars vastly improved vehicle stability making unnecessary the use of heavy duty springs and shock absorbers for competition. At the same time, riding comfort in normal touring use was not sacrificed.
Other changes included adding an inch to rear suspension rebound travel for better wheel adhesion under severe road conditions.

It states that GM has added an inch in rebound travel to the 1960 car. If I'm reading it correctly wouldn't an inch in rebound give the car a higher stance at the rear. Stewy