F41 spring replacements

[steve styllis]

Hi

I'm going to need to replace front and rear springs on my 69. It uses the F41 springs. Past cars that I've replaced springs on have never sat right especially at the back. Has anyone used replacement springs that actually worked ok?. I notice that there are GM licenced restoration part springs available, are they any good?. I also think I heard that you can still get real GM F41 front springs.

Any input would be much appreciated.

Steve

[Joe L.]

Re: F41 spring replacements

Steve----

Most of the licensed "GM Restoration" springs for Corvettes are produced by Eaton Detroit Spring. I have a great deal of experience with them relative to the standard-suspension 9 leaf spring. Their initial offering of about 3 years ago was, in my opinion, not very good at all. Later, they improved greatly and their current version is functionally ok but needs a lot of added work to make it close to being cosmetically correct. To accomplish this one has to remove the incorrect spring end bands, disassemble the spring, strip off the "cosmoline", paint the spring with the correct paint, install spring end cups, install more correct spring liners(you can reuse the ones they supply, but they're much thinner than OEM), and reassemble the spring. Now, keep in mind, that's for the 9 leaf spring. However, I expect you'd have to do exactly the same with the 7 leaf "Heavy Duty" spring you're after.

Actually, for F-41 suspension, the springs, front and rear are still available from GM. The front springs are GM part number 3832518 and carry a list price of $61.75 each. This is the same part number as original, so I would expect that the engineering specifications, if not cosmetic appearance, are the same as your originals. The 7 leaf rear spring is available under GM part number 354130. This is the fourth iteration of the original spring, so I don't know if its configuration is exactly like the original spring, but I would expect that the important engineering specifications would be the same in order for GM to catalog it for this application. The spring carries a list price of $477.00.

[Everett Ogilvie]

Re: F41 spring replacements

What are the chances of getting a good quality job of re-arching original F41 rear leaf springs? Can this be done such that the car still uses the original part and has the correct spring rate? Does a re-arch job "last"? Does anyone also "re-do" front coil springs?

thanks, Everett

[Joe L.]

Re: F41 spring replacements

Everett----

I do not recommend spring "re-arching". I would question the reliability of a "re-arched" spring and, personally, I would never use that procedure. I believe that, in many cases, the original spring can be serviced by simply disassembling, cleaning the leaves thoroughly, painting with the correct paint, installing new liners and reassembling with a new center bolt. How do you know if your spring is serviceable? Very simple if the spring is still installed in the car. Measure the chassis to ground reference points shown in the assembly and some GM service manuals. If this is within specs, your spring should be ok. Also, with the spring installed in the car and on the ground at ride height, the spring should appear "flat" or with a VERY slight arch(higher at the center). If it sags at all in the center, it is not serviceable.

I don't know of any means to restore coil springs.

[steve styllis]

Re: F41 shocks too, Joe?

Joe

thanks for the response, MOST helpfull. I think I once read that the F41 type shock is still available from GM, would you happen to know the part # and if it still is?.

Thanks again Steve

[Joe L.]

Re: F41 shocks too, Joe?

Steve-----

Yes, the F-41 shocks are also still available or were the last time I checked. These shocks are not configured EXACTLY like the originals, but they are very close. The fronts are almost exact, the rears, very close, but not exact. Obviously, the "numbers" and "dates" on the shocks are not correct. Fronts are GM #3196957 and list for $41.10 each. Rears are GM #4940459 and list for $74.10 each. Bear in mind, though, that these are old technology shocks. For performance purposes, later design gas charged shocks might be better. The Delco Reactec shock is very similar in external configuration to the original, non-41 shock and will perform far better.

Either the F-41 shocks or the Delco Reactec shocks, both of which are supplied only in gloss black finish, need to be painted to match the original shock color. Gray-blue shock paint available from Quanta Products works very well in this regard.

[steve styllis]

Re: F41 shocks too, thanks,Joe

Joe

Thanks again

Steve