Ten tips for ASW20 canopy gas spring replacement.

I replaced mine with a 1000N spring from Eastern Sailplane. For some
reason Schleicher chose a part that must be restrained in a compressed
state before installation. I used a combination of methods collected
from various sources.

1) Before you remove the old spring use a felt tip marker to mark
where the piston rod enters the cylinder at both the maximum and
minimum travel.

2) Remove the bolt and nut from the tail end of the spring. Nothing
dramatic happend on mine when I pulled the bolt. Gas springs expand
rather slowly. However the spring will expand once it is free so use
caution.

3) Unless you want to work on this for several years leave the hinge
eye bolted in place on the nose end of the spring. Unscrew the piston
rod from the hinge eye to remove the spring. Also unscrew the hinge
eye from the piston rod on the new spring. If you use any tools on the
piston rod be sure to grip it on the unused area beyond the most
compressed mark.

4) Transfer the felt tip marks from the old spring to the new one. The
new spring must be compressed somewhere between these marks.

5) Cut a 1/16 inch wide x 1/16 inch deep groove around the outside of
the fixed (black) hinge eye. I used a dremel with a cutoff wheel.

6) Center punch then drill a 3/32 inch hole through the piston rod.
The hole must be on the "unused" end of the piston rod beyond the mark
that represents the most compressed length.

7) Compress the spring to a length between the marks. You can use a
very large capacity vice, woodworking clamps or drill press to
compress the spring. I used a 2x4 stud with one end under an anchor
point about 18 inches off the floor and my 12 year old son pushing
down on the other end.

8) While the spring is compressed wrap two loops of safety wire
through the hole in the piston rod around the groove you cut on the
outside of the hinge eye and wind up the ends of the wire to tighten
the loops. A power pilot friend gave me some wire that measures about .
040 inch diameter.

9) Before fitting the new spring make sure the strut mount flanges are
parallel, correctly spaced and the holes aligned. These are very soft
and mine were out of alingment. You can use the hinge eye you removed
from the new spring to test fit the bolt.

10) After cutting the safety wire don't try to remove it with your
fingers. It is surprising how deeply the end will penetrate into your
finger tip.