Rear Leaf corrosion....too much?

[Jim V.]

Here are some pics from a 1971 rear leaf spring after disassembly and light clean up. I was hoping to restore but now have my doubts.

Is this amount of corrosion / pitting excessive or should I chillax and let er rip.....?

Thanks...

[William C.]

Re: Rear Leaf corrosion....too much?

Jim, given the degree of pitting, I'd look at replacement.

[Jeff S.]

Re: Rear Leaf corrosion....too much?

Jim

I would at least replace the main leaf. You've lost a lot of cross sectional area between the cushion cup and the start of the next leaf due to that deep pitting. When I last checked (maybe 6 months ago) Eaton would sell this leaf alone -- although not cheap; as I recall it was about $145 for my '66.

Jeff

[Joe R.]

Re: Rear Leaf corrosion....too much?

I agree with Jeff that if original appearance is important, a good compromise would be to replace just the main leaf. The Eaton main leaf is pretty much 100% correct in appearance, while the other leaves are about 90% correct. On the other hand, if having exact original appearance is not important, just buy the entire Eaton spring.

[Gene M.]

Re: Rear Leaf corrosion....too much?

replace the whole thing. The car may not sit straight if you piece it up.

[Steve L.]

Re: Rear Leaf corrosion....too much?

replace the whole thing. The car may not sit straight if you piece it up.

Why would that be?

[Joe L.]

Re: Rear Leaf corrosion....too much?

Jim-----


By the way, the type and degree of pitting and other wear your spring leaves evidence is VERY common, even with Corvettes that have lived their lives in a "non-corrosive" environment and which, otherwise, have very little corrosion seen anywhere on the car.

One of the reasons for this is that the springs were coated with the Ikonklad coating only on the TENSION surface (i.e. the lower surface). The upper surface was not coated and left bare steel. If both surfaces had been coated, none of this would have occurred. Usually, the Ikonklad surfaces are "pristine".

[Steve L.]

Re: Rear Leaf corrosion....too much?

Jim-----

One of the reasons for this is that the springs were coated with the Ikonklad coating only on the TENSION surface (i.e. the lower surface). The upper surface was not coated and left bare steel. If both surfaces had been coated, none of this would have occurred. Usually, the Ikonklad surfaces are "pristine".

Joe,
What is Ikonklad. There is nothing in Google. I've never heard of it.

[Joe L.]

Re: Rear Leaf corrosion....too much?

Joe,
What is Ikonklad. There is nothing in Google. I've never heard of it.

Steve----


I think I spelled it wrong. It might be Ionoklad or, maybe, even some other spelling. It's the thick, gray coating that was applied to the tension surface of the spring leaves. It's usually very notable when a spring is disassembled.

It's available from Quanta in pint cans. They say it can be either sprayed or brushed on. I think it's way too thick to spray and I wouldn't want to thin it. Just apply it with a brush to a CLEAN, NON-OILED surface. I apply to to both sides and edges of the spring leaves.

[Steve L.]

Re: Rear Leaf corrosion....too much?

Joe,
Ionoklad made by United Paint and Chemical Corp.
This is a patented zinc-rich welding primer developed in 1961

I don't see it on the Quanta site. The patent has probably run out. I see this kind of stuff at most welding stores.

[Patrick H.]

Re: Rear Leaf corrosion....too much?

I don't see it on the Quanta site.

Steve,

It's there - but not listed under the Ionoklad name:

http://www.quantaproducts.com/prodinfo.asp?number=28-02

[Gene M.]

Re: Rear Leaf corrosion....too much?

Steve, the spring may not exert the same force at each end if assembled with used leafs that are not assembled in the same direction as disassembled or not virgin to the assembly. The deep pitting and corrosion results in different (less than new) deflection forces. I can assure you it is not even corrosion on both ends of each individual leaf. So assembling it back as it was will not be same resultant force deflection on both ends.

A spring shop can balance and re-arch it to give functional assembly. But why not use a whole new spring and avoid all that work, expense and time?

[Steve L.]

Re: Rear Leaf corrosion....too much?

Steve----


I think I spelled it wrong. It might be Ionoklad or, maybe, even some other spelling. It's the thick, gray coating that was applied to the tension surface of the spring leaves. .

Joe,
Why would they only apply it to the tension surfaces?

Maybe they are thinking that stress cracks introduced because of corrosion on the tension side is more deterimental than on the compression side.

In any case, you'd think that dipping the whole spring in a tub would be easier than brushing or spraying one side only.

[Steve L.]

Re: Rear Leaf corrosion....too much?

A spring shop can balance and re-arch it to give functional assembly. But why not use a whole new spring and avoid all that work, expense and time?

Because we have all read about how none of the aftermarked springs give the correct height. And once I re-install it and get the body back on, I wouldn't be in very good humor, if the body was way up and I had to redo-the spring again.

What you say about the corrosion not being equal on both sides resulting in unequal forces makes sense. But I wonder if the corrosion was that bad, the spring would be toast. Which brings back the OT question "how much corrosion is acceptable?"

I would suspect that it depends on where it is, how deep it is. If it's near the diff and on the tension side, it would be worse than if it's on the ends.

My main leaf broke right in the middle under the diff bolts, 3 of the 4 bolts were broken, the diff ears were broken and the top spring had a corner missing. By some miracle the whole thing held together. I stopped driving it when I noticed the ears broken. But it wasn't obvious that the main spring was broken until I took everything apart. I didn't see any excessive corrosion to warrent the break. But it was broken for a long time since the break edges were well rounded from wear.

[Joe L.]

Re: Rear Leaf corrosion....too much?

Joe,
Why would they only apply it to the tension surfaces?

Maybe they are thinking that stress cracks introduced because of corrosion on the tension side is more deterimental than on the compression side.

In any case, you'd think that dipping the whole spring in a tub would be easier than brushing or spraying one side only.

Steve-----


I don't know why the coating was applied to the tension surfaces only. However, that's what it says on the prints for the spring and that's exactly how it appears on every original spring that I've dis-assembled. Usually, though, the coating was rather "sloppily" applied and the edges and a small portion of the adjoining upper surfaces of the leaves got coated, too. The reason that only the tension surface was called out to be coated may very well be exactly as you've surmised. That's what I always figured, myself.

Also, ANY pitting type corrosion on the spring WILL affect the functionality of the spring. That's the inherent nature of a spring. It will also render the leaves more susceptible to breakage. How much is too much? It's impossible to quantify. However, one may find out when a spring leaf breaks in service. That's called the "empirical method" of determining how much is too much.