Having done some work on the hydraulics of my tractor and log lifter/splitter, I’m puzzled by the complete lack of any provision for bleeding air out of the systems. I’ve mentioned this to a couple of tractor mechanics, but get blank looks: either it’s never occurred to them, or the answer’s so obvious that I must surely be an idiot. The nearest I got to an answer is that air, but not fluid, will pass the pressure seals, so the system bleeds itself. I find that hard to believe. Even if it is the answer, one would need to have a cylinder orientated with its pressure seal high, so the air was against the seal, but of course that may not be feasible.

Whatever the answer, I was pleased to find that the front-end loader worked fine, with no evidence of ‘bounce’, even after having had to reinstall the cylinders nearly full of air. However, one of the the log lifter’s pressure relief valves squeals a bit. Might this be because the cylinders and pipes are now full of air/oil ‘cream’? (Distant memories of Citroen warning about never pressurising the oleo-pneumatic system if there were any air in it. I believe it took ages for the air and oil to separate).