I have noticed that in one of the hand books it recommends 'lubricating' the springs with sump oil. Is this for rust control or to reduce leaf friction or both?
If this is necessary would it be better to use WD or Inox etc. to get better penetration/coverage?
Regards,
John

As far as I know, WD40 is not really a lubricant, but rather is a fish oil based multi purpose solvent. While it has limited lubricating qualities, I don't think it would work well on spring leaves. I have just repainted my '31 Coach springs, so am anxious to hear what the experts say.

I don't know what the experts will say, but I've successfully used a product from John Deere that comes in a spray can. When sprayed on spring leaves (when spring is apart) it coates them with a black graphite compound. It looks good and the springs seem to flex better as a result.
Sid

For old original springs that have not been restored,

Mix 1 part oil with 1/8 part mineral spirits.
Use a 1 inch cheap chip brush and brush the oil onto the sides of the springs.
The thinned oil will creep in the springs by capillary action.

Look up the directions for my restored springs using graphite paint. This is the Real way to go when restoring your springs someday.