I had presumed the engine running would have been a given...as our good friend COOL pointed out...otherwise the valve would not get hot...indeed, there'd be no fluid flow !
One other point...a 'drive on' four post lift is the easiest way to adjust the suspension, as you could now stand under the vehicle and have access to the leveling valve.
Any other method needs carefull concideration to personal safety being as the engine will be running and the vehicle raising itself fully up and fully down....not a situation where you might want to be.
Drive on floor ramps for the rear will work and the angle will not affect the bleeding proceedure......having done it myself that way.....but as always, safety first.
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