VCCA Home Forums TECHNICAL - GENERAL Trucks and Vans Shock Absorber Fill Plug

We keep making progress on my friend's 1949 3100.

A few weeks ago we were checking the single acting shocks. Surprisingly they do not seem to be leaking around the shaft. Of course that is when the vehicle is not being driven. So we might not be so lucky in the long run.

I added some fluid to the rear shocks through the fill plug in the stamped steel cover on the end of the shock.

When I started to do the same for the front shocks I saw that there is no fill plug in the cover. I was even more surprised when I checked the shop manual. It states that you need to replace the cover with one that has a fill plug.

Am I understanding things correctly? It appears that the shocks were manufactured with no provision to add fluid. I do not think you can fill one through the relief valve port.

My 38 fronts have the fill plug in the cover and I thought all the bodies were the same with different arms with the resulting difference in part numbers.
Tony

My experience with restoring the front suspension on a vehicle that shows no, little, or the history of its maintenance is dubious, is to look at the entire suspension system as a unit where each component should be replaced. Dubious I define as: little or no available history of suspension work, the vehicle has been in storage for a long time.

It is a lot of hard work rebuilding a suspension system including replacing old tires. It is major surgery and expensive to replace the shock absorbers. Work must be carefully planned to end up not backtracking to redo/replace parts that have worn prematurely.

It is common to leave the shocks as one of the last items for restoration hoping that they don't leak. I say if you are not 100% sure of a set of shocks replace them. Make sure you understand and follow your manuals directions, and do a SEARCH of our past posts to build a knowledge base before just taking things apart.

Purchasing a set of shocks should be from a reputable builder not someone who is on ebay with a NOS set, etc. You need a dealer who warranties his work.

Most (me included) do the cheap stuff first hoping that solves suspension problems. You should never judge your suspension system by assuming a set of 20 year tires, unbalanced, on bent rims are okay. A professional alignment is also a necessity.

Good luck, Mike

Hi Mike,

I agree that you need to keep thinking ahead on a major project like this. Overall we have the suspension and steering in great shape. We did replace kingpins and bushings. I took the steering gear apart and checked everything for damage and wear. After I assembled it I did the adjustments in the proper sequence. I have an oz-in torque wrench I made so it is really easily to set the proper clearances and measure the resistance to turning. The box feels really good and the truck steers great.

I was surprised because I was expecting the shocks to be completely empty when I was checking them. That was my experience with my ”˜37. These shocks showed no signs of leakage around the shaft and there was resistance through most of the stroke. You could tell that they were a little low on fluid because there was not resistance through the full stroke. That is why I was adding fluid.

I replaced the seals on my front shocks on my ”˜37. It was only limited success to stop the leaking due to the pitting on the shaft. Rather than mess with having the shaft sprayed welded and machined I took the cheap route. I converted to tubular shocks and am doing the same for the rear. The total cost is about the cost of rebuilding one shock and the end result is a better ride because the shocks are double acting.

That is our back-up plan for the truck. If these shocks start leaking too much we will convert to the ”˜54 truck shock set-up.

That is what is great about this old car hobby. There are always multiple solutions.

Tony,

I was surprised when I saw there was no fill plug on the front shock covers. All I can figure out is that someone at Chevy saw a cost savings opportunity by eliminating them. The reference in the shop manual confirms that it came from the factory that way.

I am considering removing the covers to drill and tap them for a plug. Or maybe the covers from my ”˜37 front shocks will fit. I agree that all of the single acting shock bodes look similar especially in that area.