Author Topic: F41 rear springs  (Read 10847 times)

x66 714

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F41 rear springs
« on: February 06, 2019, 11:45:55 AM »
Is there any physical differences between F41 rear springs & standard rear springs on a 1969 SS396? Thank you, Joe
See America's First, Chevrolet

1968 Z/28 Corvette Bronze. Black Hounds Tooth. 02E Los Angeles born 3/13/1968 pnt OO. Purchased March 1976
1969 SS396 Yellow/Yellow 08E Norwood born 8/28/1969 pnt 76E. Purchased April 1981

bertfam

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Re: F41 rear springs
« Reply #1 on: February 06, 2019, 02:45:29 PM »
Although the load rates are different, I don't believe there are any physical differences, but I've not seen very many F41 springs in my life!

Ed

69Z28-RS

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Re: F41 rear springs
« Reply #2 on: February 06, 2019, 02:49:30 PM »
By 'physical differences', I'm assuming you mean 1) leaf thickness?  2) number of leaves?   3) leaf length or clamps maybe?  What else could affect leaf spring rates other than those parameters?
« Last Edit: February 06, 2019, 03:25:12 PM by 69Z28-RS »
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bertfam

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Re: F41 rear springs
« Reply #3 on: February 06, 2019, 02:55:23 PM »
Quote
By 'physical differences', I'm assuming you mean 1) coil wire diameter, 2) number of coils, and 3) unloaded height?   I don't see how the spring rates could differ without one or more of those parameters being changed.

Rear springs Gary.

Ed

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Re: F41 rear springs
« Reply #4 on: February 06, 2019, 03:18:28 PM »
Thanks for pointing out my blindness Ed!  :)   I updated that prior post to reflect the 'physical parameters' (that I'm aware of) for leaf springs.. :)

Maybe I'll learn something by replies to that one since I've never spent a great deal of time on leaf springs... :)
09C 69Z28-RS, 72 B 720 cowl console rosewood tint
69 Corvette, '60 Corvette, '72 Corvette
90 ZR1 red/red #246, 90 ZR1 white/gray #2466
72 El Camino, '55-'56-'57 Nomads, '55-'57 B/A Sedan

x66 714

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Re: F41 rear springs
« Reply #5 on: February 06, 2019, 03:23:33 PM »
By 'physical differences', I'm assuming you mean 1) leaf thickness?  2) number of leaves?   or ?  What else could affect leaf spring rates other than those parameters?

That's my point. I too will watch for other posts.
Congrats on your reading course :)...Joe
See America's First, Chevrolet

1968 Z/28 Corvette Bronze. Black Hounds Tooth. 02E Los Angeles born 3/13/1968 pnt OO. Purchased March 1976
1969 SS396 Yellow/Yellow 08E Norwood born 8/28/1969 pnt 76E. Purchased April 1981

bertfam

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Re: F41 rear springs
« Reply #6 on: February 06, 2019, 03:51:04 PM »
There were 18 different leaf springs used in 1969, and although there may be minor physical differences between them all, would you know what to look for when trying to find an F41?

My 1969 Corvette came with F41 suspension and this model was easy. There were only 2 different rear springs used in production (standard and F41), and yes, there were physical differences. The standard 9 leaf spring was a "progressive rate" spring with 6 "arched" leafs and 3 "flat" leafs. The F41 7 leaf spring was a "single rate" spring with 7 "arched" leafs. Some of the leafs on the 7 leaf spring were thicker than any of the leafs on the 9 leaf spring. Easy peasy!

However, we would need to find someone with all 18 versions of the 1969 Camaro leaf springs to put them side by side and measure to see what the differences are. But in this case, all we need to do is find someone with a set of F41 springs and one of the many "standard" springs to see if there are any discernible differences.

I'll ask Jerry if he has any info on this since he's probably seen more springs in his life than most anyone else!

Ed

bertfam

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Re: F41 rear springs
« Reply #7 on: February 06, 2019, 04:39:40 PM »
Kurt just brought up a good point! Going by the 1969 SPRING TABLE, a spring might be a base spring on one vehicle but an F41 spring on another!

For example, the BZ spring (P/N 3955739) was one of the standard springs used on the Convertible with L48 (among outhers), but it was also the F41 spring on the 6 cylinder Coupe with JL8 (among others).

So one mans "standard" spring was another mans "F41"!

Here's a table I found in the P&A showing some of the differences in the length of each leaf (this is a 1968 chart), so yes, there were differences, but minor.

Ed

x66 714

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Re: F41 rear springs
« Reply #8 on: February 06, 2019, 04:41:10 PM »
This started with me trying to find shocks for the SS396. The car I have is a dealer demo but have no papers. Now I see there is different shocks for different suspensions plus different transmissions. I know F41 is not common & the car probably doesn't have it but I wanted to do the research another way. I also changed the front springs in 1981 so I don't have the code from them. That would've helped...maybe.
There is a 375hp car in town that has F41. Maybe I can get with him next week. Thank you, Joe
See America's First, Chevrolet

1968 Z/28 Corvette Bronze. Black Hounds Tooth. 02E Los Angeles born 3/13/1968 pnt OO. Purchased March 1976
1969 SS396 Yellow/Yellow 08E Norwood born 8/28/1969 pnt 76E. Purchased April 1981

bertfam

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Re: F41 rear springs
« Reply #9 on: February 06, 2019, 05:42:03 PM »
In reality, there are only two rear shock types available for the Camaro. With single leaf or with multi leaf. You can go economy like Monroe, or performance like KYB, but it all depends on how stiff you want the ride to be. Go to Rock Auto and browse around to see what's offered.

Ed

x66 714

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Re: F41 rear springs
« Reply #10 on: February 06, 2019, 05:56:08 PM »
I was thinking OEM, like 3192432 rear & 3192481 front....Joe
See America's First, Chevrolet

1968 Z/28 Corvette Bronze. Black Hounds Tooth. 02E Los Angeles born 3/13/1968 pnt OO. Purchased March 1976
1969 SS396 Yellow/Yellow 08E Norwood born 8/28/1969 pnt 76E. Purchased April 1981

bertfam

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Re: F41 rear springs
« Reply #11 on: February 06, 2019, 06:05:14 PM »
If you're referring to reproduction spiral shocks, unless they've gotten better over the last few years, I'd stay away. From what I hear they ride horrible and don't last at all.

Ed

x66 714

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Re: F41 rear springs
« Reply #12 on: February 06, 2019, 06:08:02 PM »
Actually Ed I'm thinking about having an old set of originals restored. I've heard the horror stories about the aftermarket shocks...Joe
See America's First, Chevrolet

1968 Z/28 Corvette Bronze. Black Hounds Tooth. 02E Los Angeles born 3/13/1968 pnt OO. Purchased March 1976
1969 SS396 Yellow/Yellow 08E Norwood born 8/28/1969 pnt 76E. Purchased April 1981

KurtS

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Re: F41 rear springs
« Reply #13 on: February 06, 2019, 07:39:09 PM »
Few, if anyone, will restored those shocks.
Kurt S
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x77-69z28

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Re: F41 rear springs
« Reply #14 on: February 06, 2019, 08:42:38 PM »
I agree to stay away from the repro shocks. They suck! P.S. Happy Birthday Joe!
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