Hi Heikki,
This is Craig, I’m hijacking Betsey’s account again.
Hopefully this will make sense.
There are two ways to mount gas springs. Here is a picture showing the two ways.
The picture shows the hatch in the open position with the gas spring extended and it shows the hatch in the closed position with the gas spring collapsed.
Style 1 is, in my opinion, a less desirable configuration. Since the gas spring mounts closer to the hinge, it must be stronger to hold the hatch open and therefore, it puts more stress on the hatch and the hinge.
Style 2 puts the force farther away from the hinge and therefore requires a lighter spring. Since the spring is lighter, it puts lower stresses on the frame and hinge.
The next picture group shows how to lay out the mounting locations, for the gas springs. It is easiest to start by sketching everything out full size on a piece of cardboard or plywood. Sketch your hatch in the open and closed positions. (big black arcs) Include the hatch hinge location. (white circle)
Step A1 Determine where the gas spring will attach to the hatch. Start with a location slightly less than the length of the extended gas spring. Draw an arc from the open hatch to the closed hatch. (The arc center should be at the hinge center)
Step B1 Draw an arc, (the radius is the length of the extended gas spring) from the OPEN hatch location (from Step A1).
Draw an arc, (the radius is the length of the closed gas spring) from the CLOSED hatch location (from Step A1). (see pointer #4 below when figuring out the closed gas spring length)
Step C1 The intersection of the two arcs drawn in Step B1 will be the mounting location of the body end of the gas spring. Compare your drawing to your teardrop. See if the location you have found will work OK.
Step A2-C2 Try changing the location where the gas spring attaches to the hatch. (in this example, I have increased the distance) See how this affects the body mount location.
(It is possible to get a solution where the body mount is not physically on the body)
Here are a couple pointers to keep in mind:
1. The further you mount the spring from the hinge, the less stress the spring puts on the hatch and hinge.
2. The further you mount the spring from the hinge, the lighter the spring needed to hold the hatch open.
3. The spring should be mounted with the plunger down, when the hatch is closed. This will allow the lubricant in the gas spring to help keep the seal from drying out. If the seal dries out, the compressed gas leaks out and the spring loses some of it’s force.
4. When figuring out the closed length of the gas spring, add a little bit to the length. This will prevent the gas spring from bottoming out and binding.
For more info and pointers go to:
http://www.mcmaster.com/
In the search on the left, type in “about gas springs”
You will see a page from their catalog that shows a lot of info about selecting and mounting gas springs.
Hope this helps,
Craig
by Nigel » Sat Jul 05, 2008 4:02 am 
John,.
However when closing it only closes half way of the shock and it doesnt swivel over to shut.
