1972 BB w/ A/C spring question

[Tom L.]

For a while I've suspected that the right front spring in my car was not working as it should, the corner is low. I've lived with it since it is common for these cars to sit un-even. This week I removed the springs. Here's what I found:

1. Broadcast code tags intact and could read the LF tag which read HV, the other was not readable.

2. The LF spring stood 15" tall and the RF spring stood 14 1/2" tall (Too short, which I suspect is the reason that corner was low)

3. There were spacers under each spring, part #1502-1/2" made by a company called Specialty products, I searched and found it easily. Dirt, grease and grime suggest they've been there a looooong time.

Before I ask any questions, any comments on my findings?

[Joe L.]

Re: 1972 BB w/ A/C spring question

For a while I've suspected that the right front spring in my car was not working as it should, the corner is low. I've lived with it since it is common for these cars to sit un-even. This week I removed the springs. Here's what I found:

1. Broadcast code tags intact and could read the LF tag which read HV, the other was not readable.

2. The LF spring stood 15" tall and the RF spring stood 14 1/2" tall (Too short, which I suspect is the reason that corner was low)

3. There were spacers under each spring, part #1502-1/2" made by a company called Specialty products, I searched and found it easily. Dirt, grease and grime suggest they've been there a looooong time.

Before I ask any questions, any comments on my findings?

Lynn-----


Was the unreadable spring tag the same color and configuration as the readable tag?

[Tom L.]

Re: 1972 BB w/ A/C spring question

IMG_2053.jpgSince I have little to lose I went out and cleaned them with a mild soap. They are both green and marked HV. I've attached a pic.

[Joe L.]

Re: 1972 BB w/ A/C spring question

[ATTACH=CONFIG]37493[/ATTACH]Since I have little to lose I went out and cleaned them with a mild soap. They are both green and marked HV. I've attached a pic.

Lynn------


I have little doubt that they are original to the car. Whether, or not, they are correct for the year and application.

As far as the length difference is concerned, the shorter one may have slightly "collapsed", assuming it was ever "right" to begin with. Certainly, there was at least some variation in the parts when new. Is there more corrosion seen on the shorter spring than the other? Corrosion damage will cause a coil spring to lose its original configuration.

As far as the "spacers" go, are these like hard rubber "do-nuts" that install in either the lower control arm spring pocket or the frame's spring tower seat? If so, I don't know that these were ever installed in PRODUCTION, although it's very possible they were. However, whether or not any were installed at the factory, I believe these were installed as part of a GM-specified field fix at the dealer if an owner complained about low ride height. In 1972 there was no spring available in the GM parts bin for a Corvette that would have produced a higher ride height.

[Terry M.]

Re: 1972 BB w/ A/C spring question

[ATTACH=CONFIG]37493[/ATTACH]Since I have little to lose I went out and cleaned them with a mild soap. They are both green and marked HV. I've attached a pic.

I know it is a lot of work, but you could swap sides for those springs and see what happens. By the time they even out none of us will be around to care.

[Edward J.]

Re: 1972 BB w/ A/C spring question

For a while I've suspected that the right front spring in my car was not working as it should, the corner is low. I've lived with it since it is common for these cars to sit un-even. This week I removed the springs. Here's what I found:

1. Broadcast code tags intact and could read the LF tag which read HV, the other was not readable.

2. The LF spring stood 15" tall and the RF spring stood 14 1/2" tall (Too short, which I suspect is the reason that corner was low)

3. There were spacers under each spring, part #1502-1/2" made by a company called Specialty products, I searched and found it easily. Dirt, grease and grime suggest they've been there a looooong time.

Before I ask any questions, any comments on my findings?

LYNN, A 1/2 inch ride hieght is not a big problem, take into consideration that the right side of the car maybe a little heavier with some of the a/c componets on that side of car. it can add another hundred pounds, And with the driver weight, it may very well be close to level. Also sometimes alignment spec.s such as camber being out it will cause slight height variation.

Now that the front part is addressed, theres the rear, Leaf spring cushions that are compressed badly and rear alignment problems also affect front ride height.

My advice is to clean them up paint them and re-install them and maybe switch sides as Terry says. Stay away front coil spring spacers.

Are you doing a frame off on your car? reason I ask is if your rebuilding the rear suspension and front suspension once done you may find the car sitting level when all done.

[Tom L.]

Re: 1972 BB w/ A/C spring question

Thanks for the replies. I am doing all this with the body on, not sure that's the best approach though.

While it may not be 100% accurate, but I suppose it can be used as a guide, I checked the AIM trim heights for the car. the "P" dimesnion from the floor to the lower lip of the front fender should be approximately 27 1/3" (+ or -). I looked back in my notes from last year when I went through the rear suspension, the Left front "P" dimesnion was 26 5/8" and the RF was about 1/2" lower.

The difference in heght from left to right is not my real concern although the difference in spring height may explain it. My concern is that there were 1/2" spacers under each spring and the car still sits 3/4" low on the LF and about 1 1'8" low on the RF. Considering the location of the spring in relation to the spindle the shim should raise the car approximately and inch, didn't do the math though. If I were to simply switch springs and remove the slacers the The diffeence in height may be corrcted but the car will sit even lower.

One additional thing that I notices since posting. The shorter spring no longer stands straight, it is curved. Not sure what that means.

[Joe L.]

Re: 1972 BB w/ A/C spring question

Thanks for the replies. I am doing all this with the body on, not sure that's the best approach though.

While it may not be 100% accurate, but I suppose it can be used as a guide, I checked the AIM trim heights for the car. the "P" dimesnion from the floor to the lower lip of the front fender should be approximately 27 1/3" (+ or -). I looked back in my notes from last year when I went through the rear suspension, the Left front "P" dimesnion was 26 5/8" and the RF was about 1/2" lower.

The difference in heght from left to right is not my real concern although the difference in spring height may explain it. My concern is that there were 1/2" spacers under each spring and the car still sits 3/4" low on the LF and about 1 1'8" low on the RF. Considering the location of the spring in relation to the spindle the shim should raise the car approximately and inch, didn't do the math though. If I were to simply switch springs and remove the slacers the The diffeence in height may be corrcted but the car will sit even lower.

One additional thing that I notices since posting. The shorter spring no longer stands straight, it is curved. Not sure what that means.

Lynn------


There were actually at least two different thicknesses of the spacers. You apparently have the thinner variety and that may not have been enough to get the car to "correct" height.

As far as the spring curvature is concerned, the springs do curve slightly in the installed position. So, maybe the spring took a "set". However, I don't understand why this did not happen to both springs. When I have removed springs from a C3 they were pretty much straight. When you measured the spring free length did you measure the DEVELOPED length on the curved one?

Is there any evidence of corrosion damage to either of the springs, especially the shorter one? As I mentioned, corrosion damage beyond light surface corrosion can affect the characteristics of a spring. There's also the possibility that this spring was defective from the get-go. Not all original parts were perfect.

[Tom L.]

Re: 1972 BB w/ A/C spring question

Forgot to mention anything about corrosion. Both have a petina of surface rust, no pitting that I can see at this point. There is a bit of undercoat on portions of the springs. I have not attempted to clean them yet.

Who would have put shims in? The factory, dealer? The shims that are in the car are aftermarket, made by a company called Specialty products. The part number on them is "1503 1/2" ". I was able to google the part and company. They've been in buisness since '71 so it's possible that they were installed very early in the car's life. I'm sure they are not the "factory" shims sold by at least one vendor, they don't look anything alike. I can post a pic if needed.

Oh, not sure what you mean by "Developed lenght". I stood them on the floor and measured to the highest point. Is that correct? How tall should they be un-installed?

[Joe L.]

Re: 1972 BB w/ A/C spring question

Forgot to mention anything about corrosion. Both have a petina of surface rust, no pitting that I can see at this point. There is a bit of undercoat on portions of the springs. I have not attempted to clean them yet.

Who would have put shims in? The factory, dealer? The shims that are in the car are aftermarket, made by a company called Specialty products. The part number on them is "1503 1/2" ". I was able to google the part and company. They've been in buisness since '71 so it's possible that they were installed very early in the car's life. I'm sure they are not the "factory" shims sold by at least one vendor, they don't look anything alike. I can post a pic if needed.

Oh, not sure what you mean by "Developed lenght". I stood them on the floor and measured to the highest point. Is that correct? How tall should they be un-installed?

Lynn------


I doubt that you'll find any corrosion damage under the undercoating. It sounds like corrosion damage is not a factor on these springs. So, that increases the possibility that one of these springs was defective from the beginning.

I have heard of these shims being found installed on other early C3 Corvettes with C-60 and they appeared to be original or, at least, installed at some early point in the car's life. A part like this would not have been manufactured by GM so the outside supplier is completely consistent with what I'd expect. These shims (spacers, actually) might have been obtained by GM as a "stopgap" measure and bypassed the normal parts design and development process. As such, they might have been just "off-the-shelf" pieces purchased by GM for PRODUCTION or SERVICE installation. I've never found a GM part number for them but there probably was one. Whether they were ever available through normal SERVICE channels is another matter. They might have been supplied to dealers through a zone office or other channel request to correct a customer complaint.

If you set a spring on the floor to measure height and it's curved, the curvature will reduce the measured height of the spring compared to an identical spring that is straight. DEVELOPED LENGTH is a measure of the length (or, height) of the spring if it were straight. You can measure developed length by applying a piece of tape at the very end of the spring, stretching it over the length of the spring and affixing it to each coil, and terminating at the very end of the spring. Then, remove the tape and apply it to a flat surface. Measure the length of the tape and you have the developed length.

[Edward J.]

Re: 1972 BB w/ A/C spring question

Lynn, You may want to put in a call to Eaton spring. They maybe able to give the unwound spring height. They are very knowledgible. I know there are mainly leaf springs but believe they repro coil springs to.