Jcb 8015 no controls after refilling hydraulics

[Turbokid]

Hi got a 2000ish jcb 8015. I completely drained the system and had every hose off. I've just refilled with new hydraulic oil and now the two rexroth controls don't work. The track track motors and blade works fine. Do I have to vent this side of the system? The safety switch on the left hand control console is down and making a closed circuit. Any help will be greatfully appreciated

[Muz]

The blade and tracks will most likely be a direct linkage control into the block, all the other functions will be servo operated, which on that age of machine was usually controlled by a small secondary gear pump, and its this you will need to locate and then bleed. If it doesent have a secondary pump, there will still be a low pressure circuit that powers the servo side. I'm not familiar with the machine, but your problem is finding where the air is stuck and removing it, have you tried slackening some hoses and pulling on that service to see if any oil or air comes out ? Just watch you dont take the hose right off as oil may come out at a dangerously high velocity.