Spring life???

[Mike F.]

How long is spring life??? Exactly 103,471 miles.

My neighbors father was in town visiting from Alabama (he's a Mopar guy), so I offered to take him to a local car cruise last night.
He was looking forward to a ride in the Vette and I have to say that I honestly believe him when he says "he's never had a ride like that before". All 4/10's of a mile of it.

Will this effect my judging score?

[Mike F.]

Re: Spring life???

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[Leif A.]

Re: Spring life???

That must have scared the crap out of both of you. I've never seen that before. Appears y'all and the car are none the worse for the wear. Hello, Eaton, you're not going to believe what happened...

[Duke W.]

Re: Spring life???

That spring looks relatively new or recently rebuilt. What's its history?

OE springs rarely fail unless they are overloaded (tough to do on a Corvette) or suffer from severe corrosion, which doesn't appear to be the case from the photos.

It's also possible that a surface flaw created a fatigue crack that propogated and eventually caused a fatigue failure. Most fatigue failures start from such a flaw, and they can also start from a corrosion crater. Cracks can be revealed by Magnaflux inspection, and those that might be undetectable can be stopped in their tracks by shot peening the surface, which work hardens the surface and makes it stronger and more resistant to developing cranks from microscopic surface flaws.

It's probably a good idea to have the leaves Magnafluxed when it's time to rebuild, and shot peening should increase durability, but it might be detectable during judging.

Fatigue failures can often be recognized by viewing the factured area. The area where the crack propogated is often smooth - almost polished, with the final fracture area rough surfaced.

From the photos, it looks like the sides are smooth, indicating two cracks one propagating from each side, or it could have started from the top surface and worked it's way around the sides.

If you can find a good, serviceable main leaf, just replace it. The rest of the leaves are probably okay.

Duke

[Steve G.]

Re: Spring life???

Just going through the same thing with a 69. Everything apart, springs cleaned, examined and painted. Assembled with new liners. Car is back together and I find one rear corner lower than the other. On examining the spring, now on the car and under load, there is a noticeable deviation from one side to the other, about right where yours broke. 68,000 mile car. This will be the last time I spend any time on a used main leaf. Used springs of this age are a crap shoot.

Steve

[Mike F.]

Re: Spring life???

That spring looks relatively new or recently rebuilt. What's its history?

If you can find a good, serviceable main leaf, just replace it. The rest of the leaves are probably okay.

Duke

Not sure of it's history. It's been that way since I bought the car four years ago.

Two days before I had driven it to work and was scheduled to make some dynojet runs that very morning, but thankfully the dyno shop called and had to cancel. Last September I drove it 1100 miles for the New England Regional. Fortunately it happened close to home.

Unfortunately the edges of springs 2 & 3 (from the bottom) were ground down during my "look at all of the sparks" show. We ended up doing some quick roadside repairs, cutting off a couple of inches of the already damaged springs and drove it home.

[Mike E.]

Re: Spring life???

Mike,
That is high mileage! The original owner of my 70 L46 convertible hit a rough railroad crossing in July of 1980. The rear spring broke, it also broke both ears on the rear end cover, and he had it flat bedded home at 62,439 miles. That's what it still had on it when I bought it in 2013. It was exactly in the same spot the flatbed left parked it in the spare garage, 33 years later.

[Joe L.]

Re: Spring life???

Just going through the same thing with a 69. Everything apart, springs cleaned, examined and painted. Assembled with new liners. Car is back together and I find one rear corner lower than the other. On examining the spring, now on the car and under load, there is a noticeable deviation from one side to the other, about right where yours broke. 68,000 mile car. This will be the last time I spend any time on a used main leaf. Used springs of this age are a crap shoot.

Steve

Steve------


My 1969 had about a 1/2" to 3/4" "lean" to the driver side from the day it was new. GM said it was within specifications. The problem had absolutely nothing to do with the spring. At one point, I rebuilt it and REVERSED it. This made absolutely no difference in the "lean". MANY Corvettes suffer from this problem.

[Joe L.]

Re: Spring life???

That spring looks relatively new or recently rebuilt. What's its history?

OE springs rarely fail unless they are overloaded (tough to do on a Corvette) or suffer from severe corrosion, which doesn't appear to be the case from the photos.

It's also possible that a surface flaw created a fatigue crack that propogated and eventually caused a fatigue failure. Most fatigue failures start from such a flaw, and they can also start from a corrosion crater. Cracks can be revealed by Magnaflux inspection, and those that might be undetectable can be stopped in their tracks by shot peening the surface, which work hardens the surface and makes it stronger and more resistant to developing cranks from microscopic surface flaws.

It's probably a good idea to have the leaves Magnafluxed when it's time to rebuild, and shot peening should increase durability, but it might be detectable during judging.

Fatigue failures can often be recognized by viewing the factured area. The area where the crack propogated is often smooth - almost polished, with the final fracture area rough surfaced.

From the photos, it looks like the sides are smooth, indicating two cracks one propagating from each side, or it could have started from the top surface and worked it's way around the sides.

If you can find a good, serviceable main leaf, just replace it. The rest of the leaves are probably okay.

Duke

Duke------


From what I can see, I think this spring's failure was entirely due to corrosion damage. This is, by far, the most common cause of leaf spring failure.

[Steve G.]

Re: Spring life???

Steve------


My 1969 had about a 1/2" to 3/4" "lean" to the driver side from the day it was new. GM said it was within specifications. The problem had absolutely nothing to do with the spring. At one point, I rebuilt it and REVERSED it. This made absolutely no difference in the "lean". MANY Corvettes suffer from this problem.

Half to 3/4" I could live with. This is more like 1 1/2 " and I can see exactly where it will break if left like it is, pretty much in the same spot as the op's.

I worked in the field long enough to see lots of broken springs, and corrosion was seldom the cause. Coils and leaf. They don't need to be overloaded or corroded. They fatigue and fail. Spring shops built booming businesses around it.

Steve