Front chassis spring ID - 65 Gran Sport

[65VerdeGS]

I recently replaced the original coil springs on my '65 Gran Sport. The rear springs had lost their tension long ago, causing the tail to drag, so I installed air shocks to bring the back end back up.  But, the rear springs had grown so weak that unless the air shocks were constantly inflated the car would scrape over low speed bumps or on inclined driveways if anyone was sitting in the back seat. 

 

I bought the new springs from Coil Spring Specialties, who assured me their springs are correct exact replacements for the springs provided as part of the H2 Ride and Handling package installed in most Gran Sport Rivieras.  Note that although the H2 option could be ordered for any '65 Riviera, these springs are commonly referred to as "Gran Sport springs".

 

In a separate post I'll say more about how the spring replacement affected the ride of the car.

 

I asked the shop to keep the old springs so I could inspect them. The rear springs we had no part numbers stamped on them. I checked them both closely and there was nothing on them to indicate a part number, nor remnants of any tags, or markings of any kind.

 

The old front springs had part number A720B505 stamped on each spring, in two locations, one on the inside of a coil, and again on the outside of the spring, close to the uppermost coil:

 

Can anyone confirm whether the number stamped on this spring matches up for the H2 Option front springs?  This number does not match any Buick part number from my 1965 Master Parts Catalog.  If it isn't an H2 spring, what could it be?

 

I got this car in 1983 and it was mostly original and unmolested.  Now it is possible that the front springs were replaced sometime before I bought the car, but if that's the case, why would someone go to the trouble of replacing both front springs?

 

 

 

 

[Wayne R]

Alex,  this wont answer  your question,  but about a month ago i was  reading  some old  riview  mags,

and i seen a photo of a front coil spring,  so just went back and found  this photo  of  the  front   spring,

but  was front a 1966 GS   that the owner from  PA  was doing a body off restoration.

from  Dec  2010  page 13, but the owner did not mention the numbers on the tag, or if on the metal of spring, just showed the original tag on front  springs.  and thankyou   Ray for the  terrific   Riview magazine.

interesting though  and others here may chime in.

[JZRIV]

Hey I recognize that photo. LOL. The part number on blue tag was the GM part number and a two letter code. In that case on paper tag was 1378809 in smaller font with big 5/8" high UU letters. Stamped spring number was P735B400 so they do not match each other. I have to speculate maybe the stamped number was manufacturers part number? Not sure.

Note: Front GS springs in 66 were "approximately" .032 larger in wire diameter vs standard.   

[65VerdeGS]

On 4/20/2023 at 4:32 AM, JZRIV said:

Hey I recognize that photo. LOL. The part number on blue tag was the GM part number and a two letter code. In that case on paper tag was 1378809 in smaller font with big 5/8" high UU letters. Stamped spring number was P735B400 so they do not match each other. I have to speculate maybe the stamped number was manufacturers part number? Not sure.

Note: Front GS springs in 66 were "approximately" .032 larger in wire diameter vs standard.   

Hi Jason,

 

Thanks for posting about the springs in your '66 GS that had both paper tags and stamped numbers on the on them which did not match the GM part number on the tags. 

 

The letter-numbers-letter-numbers pattern on the stamped part number of your springs matches what is on my springs.  This leads me to believe these are in fact the original springs installed on my car at the factory. 

 

Did you find similar numbers stamped on the rear springs of your '66 GS?  Mine had no stamped numbers on them.  Perhaps these springs came from a different supplier, who didn't stamp their springs, only supplying a paper tag?  You'd think all springs would be stamped, to aid in identification in case the paper tags got lost or damaged before the springs were installed on the assembly line.

 

I agree the stamped number is likely the spring manufacturer's part number.  Any idea who was making springs for Buick back in the day?  I would have thought GM made their own springs, but apparently this was not the case for Buick chassis springs.

 

Is there somewhere I can read the article that Wayne R. refers to about your '66 GS restoration?

[JZRIV]

Hi Alex,

Rear springs did not have a stamped number. I do not know who made the springs back in the day.  

If you go to the ROA website and look at the members only tab on left you will see "Index of Articles". You will need the latest password found in front of latest Riview. After opening the file, find the heading "Originality, Restoration Reference, Frame Off Articles. You will see 66 Frame Off Part I through VIII. Mostly volume 26 through 32. I believe that particular article would have been the first one which was in Volume 26 #6 because I did the chassis first. These were done around 2010 through 2016.

 

[Chasander]

Buick had its own Spring shop. Factory 3

[EmTee]

Rear springs are generally much easier to replace than the fronts are, so it's possible a PO may have replaced them at some point if the tail started to sag...

[65VerdeGS]

21 hours ago, Chasander said:

Buick had its own Spring shop. Factory 3

If Buick had its own Spring shop, do you know why they'd stamp their springs with a different part number than the GM Part # used in the Master Parts Catalogs? 

 

Are you aware of any reference that would cross over the Buick Spring shop numbers to the GM Part #'s?

 

Thanks,

 

 

 

 

[Chasander]

I worked at the complex and stopped by the spring shop occasionally and watched as the red hot rods were spun into springs. See the attached view of the spring and forge plant. I was a millwright and worked on the equipment but paid no attention to the product. (Wished on woul have). 

[Chasander]

This is a shot from my 1966 “Buick” parts book. The Buick numbers are completely different then your GM numbers. 

[Chasander]

These are rear spring Buick numbers. 

[Chasander]

I suspect GM numbers were created later in life when SPO took over parts, and contracted different manufactures to supply items. 

[RivNut]

6 hours ago, 65VerdeGS said:

If Buick had its own Spring shop, do you know why they'd stamp their springs with a different part number than the GM Part # used in the Master Parts Catalogs? 

 

Are you aware of any reference that would cross over the Buick Spring shop numbers to the GM Part #'s?

 

Thanks,

 

 

 

 

Same with camshafts. The part number and the stamped number are not the same.  I don’t have an explanation.

[OldGerman]

Had my front spring removed (63), no GS, it Shows a number C400B710 if I read it correct.

My car has AC.

 

[XframeFX]

52 minutes ago, OldGerman said:

Had my front spring removed (63), no GS, it Shows a number C400B710 if I read it correct.

Thanks Frank. I have a '63 with AC as well.

 

I like your new Avatar. You're not old!

[65VerdeGS]

21 hours ago, Chasander said:

I worked at the complex and stopped by the spring shop occasionally and watched as the red hot rods were spun into springs. See the attached view of the spring and forge plant. I was a millwright and worked on the equipment but paid no attention to the product. (Wished on woul have). 

That's pretty cool Chasander that you worked at Flint!

 

Seeing the aerial photo of the Spring and Forge plant reminds me of old WWII footage when bombers flew over industrial sites to be bombed!

 

The spring stamp mystery continues...

 

 

[RivNut]

No different than any other part number vs stamping number

 

https://www.teambuick.com/reference/nailhead_cam_specs.php

[65VerdeGS]

18 hours ago, RivNut said:

No different than any other part number vs stamping number

 

https://www.teambuick.com/reference/nailhead_cam_specs.php

Good point Ed.

 

Sure would be nice to find a similar chart for chassis springs like the one for cams as posted on the Team Buick website...

 

[RivNut]

If you look at the chart for camshafts, you will notice the same part number for cams with different casting numbers.  I think that allows for the use of a single part number to be used in various applications.  The end user would not know the difference and the dealers would not have to stock / order as many parts.  If you were to have turned your car over to a dealership while it was still under warranty for spring replacement, could you be able to tell, after so many miles on bad springs, if the exact same springs were installed as when the car was new?  Probably not.  I think that if you take what is available, you'll be happy. Especially if you've never experienced what was original.

[OldGerman]

On 4/23/2023 at 8:26 PM, XframeFX said:

Thanks Frank. I have a '63 with AC as well.

 

I like your new Avatar. You're not old!

John, Thank you for the compliment, I‘m 55. 

[BulldogDriver]

Maybe a call to Coil Springs Specialty to ask how they know the particulars of what they sell us would shed some light on the subject. 
 

https://www.coilsprings.com/

 

Ray