Agricultural garages have been recommended for this sort of stuff in the past. They're familiar with hydraulics on farm implements.

Hypodermic syringe. Enema syringe of around 60 mls (my go to brake flusher) might do. These have a conical nossle which can seal directly to small orifices, though for brake flushing I used a bit of vinyl or silicone rubber tubing

Something a bit smaller a might also work, but standard needles will be too fine (to suck, they will generate a pressure jet though) and will clog. In Taiwan they sell long wide needles with a 20 ml syringe for some unknown to me cosmetic purpose which are quite useful for stuff like carb cleaning.

Failing that an IV line "butterfly" with the needle bit cut off might help

Dunno what's readily available in The Yook.

Re cleaning solvents, safest is probably an excess of the recommended hydraulic oil. Diesel might be fine, but its a relatively crude and fairly complex mixture. WD40 has waxes and light solvents n it, which again might be fine, or possibly not, if, say, they interfere with valve operation

If its very dirty I might try ethanol to skoosh the old oil out, then a lot of (hot?) water under pressure, then more ethanol to drive out the water, then the oil, maybe changing it early in operation.

Edited by edlithgow on 10/08/2024 at 07:06