Like Step Hen said it can ot be done by hand. When the piston is fully extended that should be the max, or a little less than the trunk or hood fully open.
Check to see if you have the right parts.
The base ingredient in WD40 is fish oil, it was invented back in WW2 for the military to preserve armaments going to Europe by sea.
Thats why you can spray it on most anything and it won't harm it.