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Replacement springs for a '65 Gran Sport


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Hello all,

Ok, I'm new to this list, and here is my first post... I'm thinking about replacing the springs on my '65 Gran Sport and need some advice. I've had this car for 26 years, but that's another story! The problem is that my Riv 'sags' a bit in the rear.

Years ago I was advised by Leonard Scott (founding member of the ROA, and all around guru in his day) NOT to replace the stock coil springs. Leonard advised me to use rubber coil spring spacers, or better yet, have some spring seats machined to go on top of the springs to give a bit of 'lift' to the back of the car. Len said that repro springs were not made to the specs of the stock originals and replacing them would harm the handling of the car. He gave me this advice back in the early 1990's. I followed his advice and installed rubber spacers on the coils. Years later the spacers disintegrated and I replaced them with air shocks. This works fine, but now I'm worried that using air shocks to raise the rear will in time fatigue the shock mounts, as the coil springs are supposed to carry the weight of the car, yes?

So, my questions are these:

1) Are the Gran Sport replacement springs sold by Coil Spring Specialties and/or Eaton exact replacements performance-wise?

2) I read a post on this list saying that the springs from Coil Spring Specialties will make the car sit too high. Has anyone bought Gran Sport (H2 spec) springs from this source that can verify that the car will be at the correct stock ride height after the new springs were installed?

3) Last question - if I replace the springs am I advised to replace all 4 springs (Front and Rear) at the same time? Or can I replace the rear springs only without affecting the ride or having the car ride height affected adversely?

Thanks for your feedback. I look forward to participating in this community.


65 Riv GS

ROA #259

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hi alex.

i fitted 4 extra heavy duty coil springs from classicbuicks.com in my 65 riviera. i changed shock absorber too.i a still very satisfied with the stance & the ground clearance because the look of the car appears very "original". please see the pictures in my public photo folder.

unfortunately an airride system was fitted in the car before i put in the coil springs so i can't give you a feedback how the ride with extra heavy duty coils differs from the original set-up.

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Leonards advice still stands today in my opinion. I would not replace springs "especially" on a GS. Any competant spring shop can provide spacers in various heights depending what you need. I know some aftermarket suppliers state their springs are built to factory spec but the problem is its hard to verify spring rates as far as ride quality.....especially for the GS even if they do hit the correct ride height.

None of my experiences replacing springs on 67s over the years have been good. I've tried 3 or 4 brands and all made the car sit too high. I tend to be more particular than most so maybe the height being off doesn't bother some. My experience replacing springs was nothing but a waste of money and time.

Not sure about the 65 manual but the 66-67 manuals lists ride height usually checked with a full tank of gas. If available use that info to determine how much sag you have, then correct with appropriate spacers if necessary.

Keep in mind I'm not a 65 guy so my experience may not apply however I have seen advice from other knowledgeable people on this topic in general and it is consistent with Leonard Scotts advice from years ago.

Edited by JZRIV
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I cannot comment on anything other than Eaton Detroit Spring's springs, but to answer your question, yes. Eaton Detroit Spring's springs are built to the OE blueprints. A stock ride height spring from us will bring your Riv back to her Stock Ride Height. We would need to know if any modifications have been made to the car. Modifications often change weight, which WILL effect ride height. We can take these changes into account, and if needed, modify the spring to give you the correct ride height. We also do modified ride heights, if that's what you want.

But, please remember - Most people equate "Stock Ride Height" with where most of the vehicles they see at shows sit now. Many of them are on old or incorrect springs, and are not sitting where they sat when new. One of our biggest issues is someone installing new springs, and calling to say it raised the car. What they wanted was the height it was sitting at, not where it was as new. Call our factory at 313-963-3839 and we can help you with any ride height specs we have, to determine where Stock Ride Height is vs. where she sits now.

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I put the GS coils from Coil Spring Specialties in mine and they are perfect, it takes about 6 months or so for the front springs to settle down to the coreect height.

I can send you some pictures and data on the heights to the wheel well edges and how much they changed over time if you send me your email address.

Thanks, Eric.

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Regarding the settling of springs:

New springs will settle a bit, maybe at best 1/2 inch for coils. And this settling should take place within a 100 or so miles of real driving, not babying it. If it takes 6 months to come down, chances are it will continue to keep coming down.

Springs that continue to drop over time are over stressed, they are being asked to hold more weight than they were designed to.

This can happen not only from a spring that's "too small" (wire diameter, winding, etc.) but also from a spring that is dimensionally correct, but made from the incorrect grade of spring steel. You can check for correct dimensions at home, but if you have the wrong grade steel, there's no way for you to diagnose that yourself.

The correct grade of spring steel for automotive applications is SAE5160.

There are many many other grades of spring steel in the world, for many types of applications. And many of these other grades are less expensive than SAE5160.

Your springs' manufacturer can tell you what grade steel was used.

All of Eaton Detroit Spring's springs are made from SAE5160.

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At the risk of vearing off the original topic (springs for a '65), I will add that although I do not have vast experience with replacing coil springs, one of the first things I did to my '68 when I aquired it was to replace the rear coil springs. The car visibly sagged badly in the rear when I bought it. After much research (with the help of this forum and the ROA), I purchased "direct replacement" coil springs from Eaton Detroit Springs. I am very satisfied with the result. Although I admit I have never been able to decifer the correct chassis height dimensions from the Service Manuals to confirm, the bottom of the rocker panel sits dead level (parallel) to the ground with a full tank of gas and an empty trunk (with spare tire and jack hardware). I spent time obsessing over the height of the car after having the rear springs replaced, as the downward rear swoop of the bodyside mouldings on a '68 gives the illusion that the car sits lower in the rear. Once I realized the bottom of the rockers were level with the ground, that was good enough for me.

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If you are going to buy springs - buy them from the mfg. . The dealers buy them from them and then sell them to you . My favorite mfg. is Coil Springs Specialties . They ship fast ! Keep in mind that replacing the springs may not solve your problem . The cars sat low in the back . If you want to load your trunk up with golf clubs , beer , BBQ stuff and the like - it will sit low. Dont try and change the springs yourself - dangerous job. Leave it to your local shop. Check your manula for proper height . Have fun ,

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