A fluid source for leveraction shock absorbers

July 1, 2016 | By Staff

Question:

My friend’s 1941 Chevy Club coupe has knee-action shock absorbers built into the A-arms on the front suspension. They leak and probably will be replaced someday, but in the meantime what should he use for replacement fluid? Websites and blogs

Shock
Shock absorber fluid was common in the old days, but now it’s harder to find.

indicate people have used an array of products including jack oil, brake fluid, ATF, 20W oil, etc. My Motors manual is silent on the topic. Do you know the correct fluid?

Answer:

The correct fluid for the old lever-action shock absorbers is hard to find, but there is one source that offers it mail order, along with just about everything else you might need for a classic Chevy. What you are looking for is Item 603489S. It sells for $8 per quart. Contact them at:

Chevs of the Forties 1605 NE 112th St. Vancouver, WA 98686 chevsofthe40s.com

Also, there are a couple of suitable alternatives. Many restorers use hydraulic jack oil for the job. But a better alternative is motorcycle fork fluid. It is more expensive, but it has better antifoaming characteristics.

To replenish a shock absorber, take out the small bung on top of the shock. Use a ketchup or mustard squeeze bottle such as you would find at a diner to put in the fluid. Top up the fluid and then bounce the car up and down a few times to eliminate air bubbles. Repeat the process until no more fluid can be added. If your shock absorbers leak after that, remove them and have them refurbished. Five Points Classic Auto Shocks in California can rebuild your old ones.

Five Points Classic Auto Shocks 2911 South Main St. Santa Ana, CA 92707 classicautoshocks.com