The Stovebolt Site Forums The Shop Area General Truck Talk 46 Dual Action Shocks Question

I pulled the front shocks off the 46, I think they've been on since new. They are the dual action type. There was no resistance moving the arm in either direction. I remove the plug and got only a few drops of oil out. Have slowly re-filled them with hydraulic oil, working the arm, resting, re-filling until they appear full. There is certainly resistance now, but not uniform through the entire range of motion. The arm moves, then seems to hit a tight spot, then with more force moves again.
My question is with a properly functioning knee action shock should you expect smooth resistance in both directions like a modern tube shock or are the knee action shocks somewhat different?

First, they probably aren't "dual action". Most lever shocks work only on rebound, not compression. Second, "knee action" was a self-contained suspension system that was used on cars in the late 1930's, never on trucks. It was not very successful, and was discontinued pretty quickly. A lever-type shock should have very little restriction as the spring compresses, and a fairly stiff resistance as the spring rebounds. It sounds like your shocks have lost their fluid, probably due to bushing wear and/or worn seals.

http://theoldmotor.com/?p=159035

Jerry

It seems trucks could be ordered with dual action shocks in '46. Stock shocks were single action. For clarity there is a difference between lever action and knee action. Jerry is correct that Chevy cars had Dubonet (also called Knee Action) shocks in the '30s on some cars. In '38 they were standard on the Master Deluxe with single action lever action shocks standard on the Master. Many people use the terms interchangeably but that's not accurate and can cause confusion. Imagine telling a vendor you want xxxxx parts for knee action shocks and when they arrive they don't fit anything on your lever action shocks. Not criticizing, just informing. You are far from the first to use the term and won't be the last.

Update to my original post. Firstly they are single not dual action. So I pulled off the front, they were nearly dry with no resistance in either direction. Filled them with hydraulic oil and they recovered very well, free travel upwards and stiff resistance in the rebound direction. So excited, this has been my truck since the age of 15, some 46 years now. Thinking these shocks were likely not functioning all these years, I expected to feel the difference on my first bumpy road test. But, to my disappointment, any difference was almost unnoticeable. Did these shocks ever make a difference when new?

There is some benefit but as you see not a lot. That's why manufacturers eventually went from friction shocks to single action lever shocks to double action, to tube shocks and on from there. I had a nasty wheel hop on my '38. Overhauling the stock lever action shocks didn't solve it so I ended up putting tube shocks on the front and that solved the wheel hop.

The single action shocks, (all have been rebuilt by Apple Hydraulics) that I have on my 36 have made huge difference in the ride.