Replacing rear springs on a '65 GS

[65VerdeGS]

My '65 Gran Sport is riding on its original factory springs. 

 

Soon after I got the car almost 40 years ago I installed 1" steel spacers underneath each rear spring. That's sufficient to bring the car to the correct ride height when the car isn't carrying any extra passengers (i.e. driver only).

 

About 20 years ago I installed air shocks in the back to bring the rear ride height up when carrying back seat passengers.  Unless I pump up the air shocks the car will scrape on regular height speed bumps if I have anyone in the back seat.  Two passengers in the rear make it worse!

 

The ride height of the car without any passengers and empty trunk (spare tire and jack only) is 24" front, and 23" rear.  That's with the air shocks deflated. These measurements are from ground to the inner edge of the wheel well. 

 

I'm thinking to replace the springs with a set from Coil Spring Specialties, and replace the shocks with set of Bilsteins all 4 corners.

 

In my case would it be prudent to replace the rear springs only?  Or, should i replace all four springs at the same time? 

 

What are the pros and cons (other than cost) of replacing all 4 springs vs. replacing only the rear (sagging) springs?

 

Did Buick install different rear springs on GS cars with A/C?  My car does not have air conditioning.  Does that make a difference to the rear springs that should be specified?

 

I want to ensure the car does not sit higher than stock for a GS once the new springs are installed.  I've seen Rivieras with replacement springs that sit way too high, something I wish to avoid.

 

Anyone willing to share their experience and advice on replacing springs on a '65 Gran Sport would be much appreciated!

 

Seasons Greetings!

 

 

 

 

 

[RivNut]

All rivieras came with the same springs.  The H2 handling and suspension option was available for all Rivieras.  It included different rate springs and a faster ratio steering box, and caused the car, if so equipped, to sit an inch lower; BUT the H2 package was not part of the A9 Gran Sport option.  Talk of ‘Gran Sport’ springs is a myth that has been perpetuated over the years. 

Edited December 23, 2022 by RivNut (see edit history)

[65VerdeGS]

15 minutes ago, RivNut said:

All rivieras came with the same springs.  The H2 handling and suspension option was available for all Rivieras.  It included different rate springs and a faster ratio steering box, and caused the car, if so equipped, to sit an inch lower; BUT the H2 package was not part of the A9 Gran Sport option.  Talk of ‘Gran Sport’ springs is a myth that has been perpetuated over the years. 

Hi Ed

Yes, I've mixed up the Gran Sport and H2 "Ride and Handling" option.  Sorry about that.  Technically I should refer to the H2 option springs, not GS springs, as there is no such thing, other than the majority of Gran Sports were apparently ordered with the H2 option 

 

Your post opened with the statement that "all Rivieras came with the same springs".  Did you mean "all standard Rivieras came with the same springs"  

[RivNut]

16 minutes ago, 65VerdeGS said:

Hi Ed

Yes, I've mixed up the Gran Sport and H2 "Ride and Handling" option.  Sorry about that.  Technically I should refer to the H2 option springs, not GS springs, as there is no such thing, other than the majority of Gran Sports were apparently ordered with the H2 option 

 

Your post opened with the statement that "all Rivieras came with the same springs".  Did you mean "all standard Rivieras came with the same springs"  

No all Rivieras, Gran Sport and non-Gran Sport.  The H2 option could be ordered on any Riviera

[NC1968Riviera]

I ordered stock height springs from Coil Spring Specialties for my 68 Riv and I think the ride height is good on my car. I have not tested the ride height with anyone in the back seat tho so I can't speak to that.

[RivNut]

My 63 had the air shocks on the back but only because the previous owner towed an Air Stream trailer with it.  On both my 84 coupe and my 94 Roadmaster wagon, I removed the air shocks (stock and controlled by an on board compressor) and installed cargo coils. Rode just as smooth and with a load, the cargo coils would hold the height. Both were then fitted with standard shocks.

[dr914]

definitely four new springs and bilsteins.

[gungeey]

Where is it scraping that will be altered with different springs? have been on through bad potholes and nicked the exhaust due to the angle of one tire in and one out. I have hit speed bumps and scraped the frame under the oil pan. Are you hitting the gas tank/rear bumper?

These definitely are not off road vehicles 🤣

[Turbinator]

I’ve never had a problem scraping the bottom of my 63. When the suspension on my 63 Riv was refreshed I put on the Coil Spring Specialty coil springs. I had 4 Bilstein shocks already installed. Earlier the steering box was rebuilt. I had front and rear sway bars installed in hopes of gaining more stability. I also have the height and appearance I want of my car. CSS asked questions about my Riviera so they could make the coil springs to your requirements. 
 

[arnulfo de l.a.]

Your car has a nice stance/ height BOB .Looks like CSS got it spot on!

[Turbinator]

7 hours ago, arnulfo de l.a. said:

Your car has a nice stance/ height BOB .Looks like CSS got it spot on!

Arnulfo, actually I was aiming for a little lower but not much. The rear sway bar raised the car body about 1 1/2” in the back. I said to myself this is not going to work. The 1 1/2” raised in the back did not look right. I figured I’ll lower the car 1 1/2” all the way around with the back to stock height and the front 1 1/2” lower. As you can see the height looks stock. I can go with stock height, but no higher.

The steering and handling is by no means taught or anything like rack and pinion steering. The current steering set up is ieasy to keep in the lane AND not like a Magic carpet ride.

Stay well

Turbinator

[RivNut]

Turb,

Did you let the car settle BEFORE tightening the bushings etc?  If so, the bushings will hold the car up higher than the actual spring height. If you had Tom T. helping you with this, it was done correctly.  Just a thought. 
Ed

[EmTee]

I agree, a sway bar should have no effect on ride height.  The torsion bar only exerts pressure when there's a spring height difference between left and right wheels.

[Riviera63]

10 hours ago, Turbinator said:

Arnulfo, actually I was aiming for a little lower but not much. The rear sway bar raised the car body about 1 1/2” in the back. I said to myself this is not going to work. The 1 1/2” raised in the back did not look right. I figured I’ll lower the car 1 1/2” all the way around with the back to stock height and the front 1 1/2” lower. As you can see the height looks stock. I can go with stock height, but no higher.

The steering and handling is by no means taught or anything like rack and pinion steering. The current steering set up is ieasy to keep in the lane AND not like a Magic carpet ride.

Stay well

Turbinator

I also installed a Tom Telesco designed rear sway bar. I collaborated closely with Tom as it was being installed on my car. It does does raise the height of the rear end because of how the sway bar is installed. There is a metal plate which needs to be inserted under the rear leaf springs. I did not get the increase in height as dramatic as Bob but, did notice a slight rise. This is OK with me as I prefer my sitting a little higher than what might be normal. I have attached 5 pictures. The first 2 are shots of Bob's rear sway bar showing where/how it is attached and an in place shot. Bob kept me in the loop as he and Tom installed his sway bar. The next 2 are of my car showing the same shots and the final shot showing my car as it sits now.

 

Bill

 

 

[telriv]

You must take into consideration the rear bar installed on Turb's Riv. was NOT correct to begin with (#938) & I had to make considerable modifications to make it fit to install.  

IF I remember correctly the rear raise was more like 1/2"-3/4".

 

Tom T.

[60FlatTop]

When your goal is the overall height appearance of the car be sure to check all your body mounts. You can gain or lose 1- 1 1/2" easily there.

 

The mounts over the rear frame kick up are usually crushed to the limit. The four at the base of the firewall are next. The core support ones aren't bad but can make the hood hard to align and latch. The two oval ones at the rear tail pan hardly show compression. I have found the caged nut for the mount aft of the rear wheelwell can break free. You may have to cut an access hole in the trunk floor and patch it over to get that bolt out.

 

The heaviest part in the rear is the unsprung axle. That could be the reason so many replacement springs put the rear up too high. I had to buy two set of rears to get mine right. My rears are Just Suspension and the fronts are MOOG from NAPA. With 7.10 x 15 tires it sits just right.

 

Loosen all the suspension pivot points for the rear arms and spread the area at the serrated bushings before twisting those old rubbers to their limit, including the track bar bushing.

And tighten after setting the full weight on the springs and jouncing the car a few times.

 

In the mid-1980's I had my car at a show in original condition with 78 series tires on it. A friend came by and asked me how I got it so low, one of those rodder types. I told him the springs were shot. It was only a little over 20 years old then and was ready. There is a lot of hidden and overlooked stuff on these 50 year old cars. You need to pinpoint what is wrong and avoid collateral damage.

 

I have Delco gas shocks on mine. The fronts are actually spec'ed for 1970 Plymouth. The difference was that the lower ears were made for 5/16" bolts instead of the Buick 3/8". A rat tail file took care of that.

[gungeey]

Judging from Bill's rear antisway bar picture it looks like one more item to get bottomed out on lousy roads.

[telriv]

NO WAY POSSIBLE!!!

 

Look at it again BEFORE making that assumption.

 

Tom T.

[Riviera63]

2 minutes ago, gungeey said:

Judging from Bill's rear antisway bar picture it looks like one more item to get bottomed out on lousy roads.

Sits above the bottom of the rear end. No way this will bottom out.

 

Bill

[gungeey]

 If its lower than the axle tube It can get wacked. Of course its possible.

[Riviera63]

On 12/24/2022 at 10:55 AM, telriv said:

You must take into consideration the rear bar installed on Turb's Riv. was NOT correct to begin with (#938) & I had to make considerable modifications to make it fit to install.  

IF I remember correctly the rear raise was more like 1/2"-3/4".

 

Tom T.

 

I do remember that. Bob kept me in the loop in the process.

 

Bill

 

 

 

 

[Riviera63]

5 minutes ago, gungeey said:

 If its lower than the axle tube It can get wacked. Of course its possible.

Don't want to get into a back and forth but, bottomed out and getting whacked are 2 different things. I agree that anything underneath the car could get whacked by something on or in the road. I feel confident that I won't have any worries about my sway bar scraping the road. I am out.

 

Bill

[telriv]

Good reply Bill.

 

Tom T.

[Turbinator]

On 12/23/2022 at 10:27 PM, RivNut said:

Turb,

Did you let the car settle BEFORE tightening the bushings etc?  If so, the bushings will hold the car up higher than the actual spring height. If you had Tom T. helping you with this, it was done correctly.  Just a thought. 
Ed

Ed, it’s true Tom was the lead on the suspension. Tom knows his business for sure.

I put the new rear coil springs in  and admittedly I got them installed right. One fastener was replaced after Tom’s butt busting inspection. The ball joints were replaced with the front of the car hanging halfway off the lift. Tom has some pretty cool short cuts. I lashed the rear end  down to the vertical posts in the lift.

I like my car the way sits now. The ride is a bit stiff, but I like a ride you can feel. It’s almost like you are driving by your sense of smell and hearing. Like being ONE with the car.

I witnessed older fellows in the mid 60’s put spring clamps on the front coil springs. Then they would put concrete blocks in the trunk. The suspension was ruined on the cars I was a passenger. There is s real reason those gents are low and slow.

[gungeey]

1 hour ago, Riviera63 said:

Don't want to get into a back and forth but, bottomed out and getting whacked are 2 different things. I agree that anything underneath the car could get whacked by something on or in the road. I feel confident that I won't have any worries about my sway bar scraping the road. I am out.

 

Bill

Bill, apparently, you're out. Now we've got the guy selling the sway bar in. Bill, I'm sure your car is a great car and set up just like you want it. The thread originated as springs not supporting weight with backseat passengers. That shifted to include sway bars.

 

These were designed and manufactured as low slung cars. I think the factory passed on the sway bar option, likely for good reason. If the already low ground clearance is lessened further by adding suspension parts(ie rear sway bars configured as pictured) the propensity to bang up the underside increases ... both in road irregularities, debris and bottoming out on speed bumps and potholes. Not only is it not impossible,  it actually increases the likelihood of the car contacting the road. Please don't take it personal.

[telriv]

This could go on for days with NO ANSWERS.

 

Enough said!!!

 

Tom T.

[avgwarhawk]

Purchase a set of progressive coil springs.  Be happy. https://www.springsnthings.com/

[65VerdeGS]

On 12/23/2022 at 7:11 AM, gungeey said:

Where is it scraping that will be altered with different springs? have been on through bad potholes and nicked the exhaust due to the angle of one tire in and one out. I have hit speed bumps and scraped the frame under the oil pan. Are you hitting the gas tank/rear bumper?

These definitely are not off road vehicles 🤣

The car will scrape on the exhaust flanges ahead of the resonators which hang lower than any other part of the vehicle.  Sounded nasty, but no damage was done as I went really slow over the bump!

[65VerdeGS]

Thanks everyone for your comments and suggestions.

 

Any feedback on the question of whether it's a bad idea to replace only the rear springs?  The fronts seem just fine.

 

 

[EmTee]

5 hours ago, 65VerdeGS said:

Any feedback on the question of whether it's a bad idea to replace only the rear springs?

It will do no harm.  If the front of the car is sitting within the specs given in the shop manual, then go ahead and replace the rear springs.  Drive the car 200 ~ 300 miles after the change before making any further judgement.  What may happen is restoring the rear shifts the Cg forward and the front may then sit lower.  If the front ride height falls out of spec, the front springs may need to be replaced as well.

[avgwarhawk]

6 hours ago, 65VerdeGS said:

Thanks everyone for your comments and suggestions.

 

Any feedback on the question of whether it's a bad idea to replace only the rear springs?  The fronts seem just fine.

 

 

Not a bad idea at all.  Purchase progressive coil springs I suggested a few posts back.  These are the type of springs I used in my 54 and 60. No bottoming out.  Good ride.  

[60FlatTop]

Replacing the springs is not a bad idea as long as the person doing it is aware of the collateral damage that can occur and follows the instructions in the manual.

 

 

 

"My mechanic" would just disconnect the shocks, yank the rear end down to get the springs out, and stuff the new ones in.

[Turbinator]

On 12/29/2022 at 1:20 AM, 65VerdeGS said:

Thanks everyone for your comments and suggestions.

 

Any feedback on the question of whether it's a bad idea to replace only the rear springs?  The fronts seem just fine.

 

 

I would guess the rear coils are fine. People today are bigger, heavier than they were 60 years ago. Yeah, older gents, not all, take on weight. Look at the kids!  I’m not saying your guests that ride in the back seat are excessively heavy, but a consideration.

You mentioned exhaust pipes or muffler scraping. I had custom exhaust put in and I was lucky. Those exhaust pipes and mufflers are tucked up and welded tight as can be. I’m very fortunate to get a good install. At 55-60mph the reverb in the cabin is delightful. When the RPM’s kick up at 70-80mph you can hear the engine loud and clear.

Id examine the rear coils before replacing them. If you do it yourself it could be handful. If you’ve done it before then you know the drill.

Turbinator

Edited December 30, 2022 by Turbinator (see edit history)