Classic/Antique Car Repair: Shock Absorber Fluid for Late 30s Buick, shock absorber, auto parts store

Question
Hope you can help

I bought a 1939 Buick and am doing basic maintenance at this point (car is in good condition). The shop manual indicates that the lever action shock absorbers need to be periodically refilled. The manual specifies refill only with GM Shock Absorber Fluid. What if anything is a modern equivalent. I see enough 30's - 40's Buicks at car shows to belive that there is a substitute for this "secret sauce"

Thanks Much !

Mike

Answer
There is a fluid that is used in hydraulic jacks which is pretty close to the old GM fluid - I've used it successfully in my similar cars.  If you go to a good auto parts store and ask for Jack Oil, they should be able to help you.

There are vendors who specialize in rebuilding these lever shocks - they also will sell you the "special fluid".   Your guess is as good as mine as to what they use.  You can contact one of them at: Five Points Classic Auto Shock. (714) 979-0451

Dick