Author Topic: F41 rear springs  (Read 10946 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

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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... :)
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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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Re: F41 rear springs
« Reply #15 on: February 06, 2019, 08:47:51 PM »
From their website, I believe Dan's Shocks can rebuild them, although they typically deal in selling date-stamped NOS units. I'm not sure of the process or cost to rebuild, nor have I any personal experience with them. Could be worth a call to discuss though:
https://dansshocks.com/spiral-shocks/
Tim in Australia.
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x66 714

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Re: F41 rear springs
« Reply #16 on: February 06, 2019, 09:19:38 PM »
I agree to stay away from the repro shocks. They suck! P.S. Happy Birthday Joe!
Thank you for your advice & the birthday wish :)
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

69Z28-RS

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Re: F41 rear springs
« Reply #17 on: February 07, 2019, 03:30:48 AM »
Don't any of you run Konis on your Camaro??
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x66 714

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Re: F41 rear springs
« Reply #18 on: February 07, 2019, 10:39:55 AM »
Konis, Monroe, KYB & others are incorrect for a restoration. This might be my last car I can build. I want to try to do it as it was new....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

69Z28-RS

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Re: F41 rear springs
« Reply #19 on: February 07, 2019, 11:37:55 AM »
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

For original restored, the best (and only truly accurate) would be finding original shocks, but Ed mentioned Monroe which aren't original and don't even appear to be a simulation of original (Monroes are fine for a non-performance car) but I don't think the Monroe 500 is still being made is it? 

KYB are not original either, and I've heard of many failures with them. 

For performance (handling/braking/etc) Konis have generally been no.1 for a long time, but maybe I'm out of touch?  I'm surprised none of the fellas with Z28 s especially aren't running them.   On my car currently are Gabriel Striders (purchased long ago) - painted gray to appear like original at least in color,  but I have new Konis to replace them at some point...
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
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ZLP955

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Re: F41 rear springs
« Reply #20 on: February 07, 2019, 04:13:50 PM »
Gary I researched shocks a couple of years ago, and bought Koni shocks for front and rear, for when the time comes. At the time (probably no different now), the repro spiral shocks were described as 'for show purposes only', so like you I figured go for the best aftermarket brand and paint the original color.
Tim in Australia.
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Sold at Clippinger Chevrolet in Covina, CA.
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bertfam

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Re: F41 rear springs
« Reply #21 on: February 07, 2019, 04:17:46 PM »
Joe, I didn't realize you were restoring the car so yes, give Dan Patch a call. He's well known in the NCRS circles, but be prepared, it's not cheap to restore these!

Ed

x66 714

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Re: F41 rear springs
« Reply #22 on: February 07, 2019, 05:02:32 PM »
Joe, I didn't realize you were restoring the car so yes, give Dan Patch a call. He's well known in the NCRS circles, but be prepared, it's not cheap to restore these!

Ed

Yes, doing the entire car all over again. You saw the trunk work from a couple of months back. Pulled the subframe assm with engine & transmission yesterday.
Sent pictures of numbers to Kurt yesterday for his files. It is a born with drivetrain. Trying to fix my stupidity that I did to the car from 1982.
I did talk to Dan Patch but I need to find some core or have him renumber some others which I don't think I want to do. I figure I will probably have 1000,00 in a set of shock...or more

BTW...now retired :)
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

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Re: F41 rear springs
« Reply #23 on: February 07, 2019, 09:47:59 PM »
Do you have originals to restore? I have two rear shocks part #3192831. The google machine says they are for 67-69 Camaro, doesn't specify Z/28 though. Dates are 176/69 and 188/69 They look good, lower bushings are beautiful, just don't do any expanding on there own, need rebuilding? You can have them if they will work. PM me if you want them. Paul

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Re: F41 rear springs
« Reply #24 on: February 09, 2019, 02:38:08 AM »
 I believe rear shock 3192831 is for mono rear leaf springs. It takes a bolt an nut that goes through the bottom of shock to hold it in place.

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Re: F41 rear springs
« Reply #25 on: February 10, 2019, 01:27:02 AM »
I'm thinking there's not a big demand for date coded shocks for a mono leaf car. I guess these are headed for the metal recycler.

Thanks  Paul

x66 714

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Re: F41 rear springs
« Reply #26 on: February 10, 2019, 03:41:02 AM »
I'm thinking there's not a big demand for date coded shocks for a mono leaf car. I guess these are headed for the metal recycler.

Thanks  Paul
You might call Don Patch. He might have an interest in them...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

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Re: F41 rear springs
« Reply #27 on: February 10, 2019, 05:05:24 AM »
Hey Paul,

I wouldn't toss those shocks. Now that there are survivor classes for these Camaro's. There are plenty of Camaro's that could use them.

                                     - Warren

x66 714

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Re: F41 rear springs
« Reply #28 on: February 20, 2019, 12:23:28 PM »
Is there any physical differences between F41 rear springs & standard rear springs on a 1969 SS396? Thank you, Joe

This was my original post. I've since looked at another SS396 coupe that WAS ordered with F41 suspension. My observations was it has 4 thick leaf springs instead of 5 which is what my car has. That car also has 851 rear shocks. The 832 rear shock is called for in the AIMs book under the L35 section. I was not able to see the front shocks or springs clear enough to see numbers. No tag was in my point of view so I might have a follow up post in the future if the owner will allow me to dig deeper....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

blackss69

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Re: F41 rear springs
« Reply #29 on: February 20, 2019, 03:04:53 PM »
I am the original owner of a original unrestored 1969 SS 396/375 car with F41 suspension.  The rear springs (original) are 4 leaves with the paper tag BM (in silver).  The rear shocks (original) are UN from the Body Broadcast Sheet.  I can't see all the p/n but I think the last 3 digits on the rear shocks are 851. 

x66 714

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Re: F41 rear springs
« Reply #30 on: February 20, 2019, 04:56:44 PM »
I am the original owner of a original unrestored 1969 SS 396/375 car with F41 suspension.  The rear springs (original) are 4 leaves with the paper tag BM (in silver).  The rear shocks (original) are UN from the Body Broadcast Sheet.  I can't see all the p/n but I think the last 3 digits on the rear shocks are 851. 
This car too is 375hp original owner. 11,998 original miles. Cortez w/black top. I couldn't read the sticker on the shock but it's still there...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

blackss69

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Re: F41 rear springs
« Reply #31 on: February 20, 2019, 11:27:30 PM »
While you are looking at F41 cars I would like to know the label marking on the front springs and the label marking the front shocks and p/n if you can see it.  This is a 1969 SS 375/396 with F41 and 4.10 rear axle.  The spring chart says they are either HH or HJ front springs (do you add the weight of the L78 or is it already included in the chart?).  It is 4-speed without a console.  My car is original with less than 10,000 miles.

It also has the F44 special steering.  It has the normal AN manual steering box.  I'm not sure what else made the F44 steering vs the normal SS steering on the 396.  It is VERY hard to steer at low speeds.

Thanks

william

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Re: F41 rear springs
« Reply #32 on: February 21, 2019, 12:05:27 AM »
N44 fast-ratio steering was the standard manual gearbox with a longer pitman arm [5.75"] and shorter steering arms, same as Z/28.
Learning more and more about less and less...

x66 714

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Re: F41 rear springs
« Reply #33 on: February 21, 2019, 02:00:20 AM »
While you are looking at F41 cars I would like to know the label marking on the front springs and the label marking the front shocks and p/n if you can see it.  This is a 1969 SS 375/396 with F41 and 4.10 rear axle.  The spring chart says they are either HH or HJ front springs (do you add the weight of the L78 or is it already included in the chart?).  It is 4-speed without a console.  My car is original with less than 10,000 miles.

It also has the F44 special steering.  It has the normal AN manual steering box.  I'm not sure what else made the F44 steering vs the normal SS steering on the 396.  It is VERY hard to steer at low speeds.

Thanks
If I can find a place to take one of my other car, he will let me put the car in my garage to inspect & take pictures. Would like to post pictures in the original car details. Yours sound like something others would enjoy pictures of....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 #34 on: February 27, 2019, 03:23:32 AM »
Re: shocks
Auto or manual will affect the part #.
Kurt S
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x66 714

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Re: F41 rear springs
« Reply #35 on: February 27, 2019, 04:19:11 AM »
Re: shocks
Auto or manual will affect the part #.
Kurt. My car is TH400 w/o F41...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

blackss69

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Re: F41 rear springs
« Reply #36 on: February 27, 2019, 04:01:22 PM »
Kurt  Mine is a 4speed,  4:10 ratio differential 396/375 with F41 suspension and N44 quick steering..   There are no other options.  blackss69

x66 714

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Re: F41 rear springs
« Reply #37 on: March 21, 2019, 11:38:23 PM »
I thought I would add to this after I looked at the F41 SS396 L78 4spd here in town
Front shocks 477 sticker PS
Front springs HW 3955728
Rear shocks 851. sticker there but can't read.
Has 4 thick leaf springs. No tags on them.
Also has a longer round pinion snubber. Never seen one like this.....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

 

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