Painting rear spring

[David Z.]

I currently have the spring out of the rear of my 65 coupe. Want to repaint it while it's out. I seem to recall seeing something about them being gray but don't know where I saw that. I couldn't find the info in the older judging guide(beige cover. Maybe I didn't dig deep enough.

Could someone please point me to the correct information?

Thanks!

Dave Z

[John H.]

Re: Painting rear spring

Dave -

Quanta (www.quantaproducts.com) has the rear leaf spring gray paint; they also have all the parts to rebuild the spring in a kit (paint, liners, center bolt, etc.), but I haven't seen their liners.

[David Z.]

Re: Painting rear spring

Thanks John! Gray it is! Hope all is well with you.

Dave Z

[Patrick H.]

Re: Painting rear spring

Dave,

It would be nice if Franz E. would chime in here. No one could answer this better than him.

This may sound funny, but can you tell if your spring has ANY paint on it currently? Any sign of the original gray? If you look closely, you may see pain "dribbles" along the edge of the spring leaves. Then again, you may not, as in 1965 some were painted and some were not.

The original paint (Ikonoclad) is gray, and available from suppliers such as Quanta. To maintain authenticity, use a coarse brush to apply it. Originally I believe it was applied just to the top surface (as installed) but most people usually paint both surfaces.

Patrick

[Gary B.]

Rear spring paint; questions remain

Patrick,

The GM enginering drawings for rear leaf springs in the 63-78 time span call out the following paint spec:

APPLY 3783188 PRIMER (IONOKLAD 200 J OR EQUIVALENT) ON TENSION SIDES AND EDGES OF LEAVES, MIN COATING .0015

Now, the question is, would GM allow suppliers to paint the entire leaf, i.e., all 4 surfaces; top, bottom plus both edges? I suspect they would since it exceeds the spec. You can imagine that it might take much more time to paint the tension side and the two edges than it would to dip the leaf and cover all surfaces. In my mind the jury is still out on whether paint covers 3 sides or all 4 of mid-year springs. I'm aware of Franz's opinion, but I'm not convinced that springs were unpainted nor am I convinced that only 3 sides were painted.

Gary

[Patrick H.]

Re: Rear spring paint

Gary,

I saw an unpainted rear spring on a 1500 mile 1965 convertible two years ago. I crawled under the car and looked at it myself, because Franz and I had spent a considerable amount of time discussing this at dinner the previous evening. We discussed how the painting changed over the years, when it occurred, etc. I "may" even have a picture of the spring, but to find that....

I recently took apart the spring of a 1972 coupe. FWIW, it definitely appeared to me that there was remnant on one surface of the spring only.

I will not attempt to rephrase Franz's thoughts here, as I'll let him do that himself if he chooses. He has the advantage, however, of having been there. We do not. I'm waiting to look at more before I make my own definitive decision, but for now I am following his thoughts. I know you've done a lot of investigating into springs as well, and for that I respect your opinion.

Patrick

[Gary B.]

Rear spring paint

Patrick,

I also know of examples of NOS springs with the compression side left unpainted. I just don't know if all springs were like that, given multiple vendors and engineering changes over time. When I first started researching this paint issue, some claimed that all original springs received no paint whatsoever and that simply conflicts with the engineering specs on the original drawings, so I think that at least after some point in time, the paint spec must have come into play. I think it's likely that we'll never really know the complete history about the paint issue.

For the spring on my 66, I've chosen to paint all sides, figuring it's one less part that can rust and I think painting all 4 surfaces is consistent with what the judges expect to see.

Gary

[Franz E.]

Re: Rear spring paint

On February 24, 1962 Chevrolet engineering released chart drawing 3827453 for production. Chart drawings allow the engineering groups to select spring sections to meet their specific design requirements. Both 63 rear spring part numbers are detailed on this drawing: part number 3794095 192#/in rate standard nine leaf spring along with part number 3828811 305#/in rate Z06 option spring. There were eight “note” call outs for GM manufacturing compliance. There was no rust inhibitor specified or salt spray requirement, that came later. Rust prevention was determined by Chevrolet’s quality representative, manufacturing engineering, assembly plant and most importantly, the “supplier”. Chevrolet’s Livonia Spring operation “NEVER MANUACTURED” the Corvette transverse spring. There were two suppliers of record: Eaton Corporation, not to be confused with Eaton Spring Service on Michigan Avenue in Detroit, and Ontario Steel Products later known as North American Rockwell. Both Eaton and OSP were located in Chatham, Ontario and had similar manufacturing processes. In the discussion board archive there’s a very detail description of leaf spring manufacturing. In the mid 60’s neither facility had painting capabilities. Springs were palletized, usually 168 springs per pallet; weight was the limiting factor, then the entire pallet was immersed in “tectyl 400-C” dry to the touch oil. Problem was tectyl was a poor rust inhibitor and St. Louis constantly complained of rusty springs. Please don’t laugh; this problem was aggravated during high humidity periods. However, Chevrolet purchasing wouldn’t authorize a price increase to improve salt spray and shelf life. Only two exceptions were GMPD’s (General Motors Parts Division) service requirements and a strike bank built for the 65 union negotiations. Ionokland was authorized as a rust inhibiter on the “Tension Side only” to extend shelf life. Ionokland was applied only to the tension surface to reduce cost and eliminate the possibility of insufficient clamping torque. In the mid 60’s Ionokland had the texture of oatmeal and contained heavy concentrations of zinc, not your typical paint. It was manually applied on the assembly table prior to final spring assembly. This manufacturing process remained virtually the same until the introduction of the 2 ½” wide spring. Part number 14021604 was released March 14, 1979 and included “Ionoklad” as a “note” on the drawing. Over the years I’ve enjoyed supplying interested enthusiasts with spring drawings, specification sheets, copies of the SAE & GM’s spring design manuals to educate and increase everyone’s awareness of the actual appearance of the transverse spring. I’ve asked numerous times where did the NCRS obtain information that springs were painted???????????????? In ten years of asking never received a return call or response. Several years ago at one of GM’s Tech Center “Retires Luncheons” design engineer Osh and releases engineer Dan and myself (spring supplier) discussed the paint issue and we simply scratch our heads. Springs used for articulation studies were typically painted white to enable the technician to visually observe spring travel under various loading conditions. Those springs were painted at the Tech Center or Milford and weren’t used in production. Again, automotive archeology is no different than any other forms of archeology as new information surfaces we must objectively rethink our previous conclusions

[Craig S.]

Re: Painting rear spring

Patrick - I remember that conversation we had with Franz a dinner in Bloomington a few years ago....I have an original F41 from my 66 L72 I bought last year and it has paint only on the one side....Craig

[Jerry G.]

Re: Painting rear spring

I have a July 8th built car with F40 that had paint only on tension side.

[Jerry G.]

Re: It July 8th ,1965 *NM*

[David Z.]

Re: Rear spring paint

Franz
Thanks very much for the education! There was definitely some thick paint on the top of my spring but it looked also like all four sides had been painted somewhere along the line. No early owner history on this car so it's anyone's guess what may have been done to the spring along the ownership pathway.
Thanks again to all who responded! Neat discussion!

Dave Z