When it comes to “hydraulic”, Tonka did take liberty with the term. A true hydraulic cylinder will be filled oil whereas Tonka used a spring. This is why a Tonka dump truck will “pop” when the piston is released. A true hydraulic piston will have a slower release…as in older Buddy L and Smith Miller. But true hydraulics come at a cost…both financially and practically…they can leak! And after the fluid leaks out…after making a mess…they don’t work. In the case of Tonka…the “hydraulic” pistons often stop working with the passing years. Comprising two aluminum telescopic tubes with a spring, the aluminum tubes can often “fuse” together. There are a number of ways fix this…apply high heat to the piston…spray WD40 into the barrel…disassemble. You hope for the former…
