So am I able to adjust the slew park brake engage time by any of these?
I'm guessing the time delay is electronically controlled by the "on delay timer" in Uffex's post above. I'm not seeing anything in the picture you posted (post #25) that controls time delay.
I'd be running through that check that Uffex posted above regarding pilot pressure in the slew circuit. Questions I'd be asking are:
Is the pilot valve (joystick) leaking, or slow to drain when centered, causing a delay in pilot pressure signal returning to zero at the main control valve (where the pressure switch is)?
Is the swing spool in the main control valve not centering properly (ie worn springs), resulting in the pressure switch still seeing pressure for say 10 seconds after you stop slewing?
Is the anti-rebound/anti-reaction/cushion valve allowing bypass, which keeps the main swing working lines under slight pressure (enough to trip the pressure switch) when it shouldn't? Is this fault only noticeable when working on a slope?
Is the pressure switch, delay timer and park brake release switch working correctly?
Lastly, what is a flip flop unit?!
I have zero experience working on this brand of machine, but answering the above questions might steer you closer to the problem.