Hi All

I'm contemplating replacing my rear leaf spring in my 1978. It rides low on the drivers side.

I've been given a list of things to checkto make sure it just not installed incorrectly etc and it looks like it has just worn out.

I was on Corvette America today looking for a replacement to get shipped down here and came across two units, both covering the 1978. Can any body help with which model is likely to be in my Vette. I find it hard to tell when my existing one is installed and flattened.

Two models shown below. The top one is 1963 to 1978. The bottom one is 1978-1979. I'm thinking the 1978-1979 will be the one, but I have nothing to base that judgement on.

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Kiwi Doug

aka Harry Tasker

I just replaced my spring on my 72 with the fiberglass spring from VBP. I will never put a steal spring back on, the drive is much better and the handling is great. It was a very easy install, and weight is about 30lbs lighter.

I used the KYB gas adjust shocks also with the spring. Count the layers in your spring and see which matches. I think it was 1980 when GM put the mono spring (fiberglass) as standard.

Give a look at vette brakes products. Good luck!!!

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Click for larger view

I'm going to bet you have a 7 leaf spring in the back as I did, but I agree with fp above.  Try the monospring...my guess is you won't be disappointed.

Remember though, as fp stated you will need to change your shocks to match the damping rate of the spring, otherwise the changeout isn't as good.

I used KYB II shocks, built specifically for use with the monospring.

Good luck and let us know what your final decision is.

the difference between the two is that the early 78 models had the 2-1/4" wide leaf spring, and the late 78 and later had a 2-1/2" wide leaf spring

measure the spring in your car and that will be the answer as to which you will need. the split is from july on of that year (not sure)

No matter the size, replace it with a fiberglass spring.  Trust me.  I haven't heard of one Corvette (mainly C3 or older) owner that has regretted it.  I didn't notice any handling difference, but the ride was sooooooo much better.

* Note that the fiberglass spring also recommends newer shocks too to gain maximum efficiency of the spring.

Good luck.

My wife, Colleen had a new 9 leaf spring put on her 78, Ian. that what was originally on it.  So if you are looking for original get the same as you have. so measure the width too. Her Vette rides so much better and smoother now.  We had to put 8 inch bolts on it to get the right height in back. My 76 has a fiber glass mono spring on it and it rides smoother and better on corners.  So go with it if you better handling.  It just depends on what you want being original with everything you can or want a  mover.

I would also suggest switching to a monospring if you don't mind straying from what was original.  I put a 360# spring in my '77 and the ride and handling greatly improved.  I'd go with a 330# if you would like a softer ride.

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1977 Corvette EX-L48
383 Stroker, Holley MPFI, MSD Ignition, BTO 700R4, VBP Street/Slalom, Hooker Sidepipes with JCL Spiral Baffles, Corbeau A4s w/ Shark Bar and Simpson 5-Points, 17" AR TTII's, Kumho MX's

(click to see a bigger version)

1981 was the first year for the fiberglass spring.[QUOTE=fp_vetter72]

I just replaced my spring on my 72 with the fiberglass spring from VBP. I will never put a steal spring back on, the drive is much better and the handling is great. It was a very easy install, and weight is about 30lbs lighter.

I used the KYB gas adjust shocks also with the spring. Count the layers in your spring and see which matches. I think it was 1980 when GM put the mono spring (fiberglass) as standard.

Give a look at vette brakes products. Good luck!!!

[/QUOTE]

Thanks for all the tips. I'm still undecided about straying from an original type part. I measured it though, the rubber layers in between had me scratching my head until I took a closer and realised what they were. I found mine to be a 7 leaf 2.25 inch spring.

Just two more things I'd like to ask cos I was told buy someone else that replacing the spring will fix my drivers side height problem, it is slightly lower on the left than on the right. The previous owner replaced all the shocks with Koni adjustible shocks. I asked him whether they had anything to do with the body height, he said no. Would this be correct? What part of the suspension controls the body height, in this case on the left?

 

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Kiwi Doug

aka Harry Tasker

The springs effect the ride height.  If you ever wanted to lower the front you can either get shorter coils (the 550# coils would lower the front about an inch) or cut stock coils.  For the rear you would adjust the spring bolts... trying to remember if tightening made it higher or lower though... been two years since I replaced my spring.  I'm thinking the lower the nut on the bolt the lower the car will be, based on the fact that I know they sell longer bolts for lowering the ride height.  Also, as far as keeping your car original or going with a composite spring, the good thing is there are no permanent modifications, so you could always easily go back. VTHokie77Vette38741.7458333333

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1977 Corvette EX-L48
383 Stroker, Holley MPFI, MSD Ignition, BTO 700R4, VBP Street/Slalom, Hooker Sidepipes with JCL Spiral Baffles, Corbeau A4s w/ Shark Bar and Simpson 5-Points, 17" AR TTII's, Kumho MX's

(click to see a bigger version)

To answer your original question, I think the top spring is for the "gymkhana (sp?) suspension and the bottom is for the standard suspension.

The gymkhana suspension was an option in '78, mine has it and the ride is REALLY rough, but it handles like a champ.

If I ever get up the ambition, I'm going with the fiberglass spring.....

Dave

Loosening the nut ,lowers the hieght,if the nut is all the way down to the end,then you have to get the longer bolts

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C3VR Lifetime Member #93

your spring is the  gymkhana that was used on the 78 Pace Car as  standard.  It is bouncier and stiffer than the 9 inch which was standard on 78's unless you ordered the 7 leaf gymkhana. so both are considered original. I'd go with 9 leaf for original. It is great on Colleen's 78, Ian. click on my link and you will see pictures with one close up of the rearend.   Aegisfang38770.6972337963

Bob ,I'm not sure if we are ready,for a close up of your,rear end

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C3VR Lifetime Member #93

i had a gymkhana (6 leaf !!!) on my 78  but i went for the monospring from vpb after all i have read about it ... as long as you don't really want to keep it original i would choose the mono

 

art-corvette

I bought my car with Triangle Spring according the sticker. Is this a stiff one ??? Anybody knows this one ?

What does a fiber mono on the ride quallity ? Is it worth replacing a almost new steel one ? ( fiberspring  and schocks.... )  

hey, Ron, my rearend is still a tightbutt!    

Barry,

If you are happy with your ride, no sense in swapping springs. Looks like you have the stock standard springs. Mine has the 5 leaf gymkhana spring and it is rough as a cobb (does that phrase transfer to Belgian?)

Dave

I run the 315 lb TRW mono spring with gas shocks and am very happy with it. It gives a nice smooth ride. I have never taken my vette on a track so I can't speak on its performance characteristics. Like Autom8r says, if your happy with your ride why change out a new spring.

I have a 78 and switched over to the mono several years ago, and haven't looked back since.  The ride is so much better, and the upside is that its fairly easy to do.  So if one worries about orginality, to swap back can be done.  As far as handling goes, I do get somewhat aggresive in the mountain roads of the Adirondacks at times and the mono has it all over the gymkhana spring (which is what I had).  And it rides a lot better to boot.  During one trip I was following several C-5's who were pushing it in the twist and curves, and I pretty much stayed right with them.  But remember, even with your butt now sticking to the road, unlike the steel springs, the nose still tends to plow some when you get on it hard, unlike a C-5.  There is still a very big difference between the the C-3 and 5. 

You definitly won't be disappointed with a mono, if you do convert, change your shocks at the same time.  There are different levels of mono springs, mine is a #360. 

I'm eventually going to the glass mono spring, but is pretty far down on the "things-to-do" priority list.

Dave