Bob Chilcoat wrote:
We have been having trouble getting decent replacements for the above, which
pop into the holes in the top of the wing to allow the main gear struts to
be pressurized. Our mechanic uses 1 1/2" plastic (Polypropylene, I think)
snip
I found some better quality plastic (Nylon) from Heyco, and got some black
samples (the minimum order for the white "standard" color ones was 26,000!).
These seemed promising, but are just a bit too deep to lock in securely.
Has anyone found an acceptable substitute for the Piper part? I may have to
go back to the steel knockout plugs, or machine my own design (I have a
lathe and milling machine, fortunately).
sig snip

On the later PA28's (can't remember about the 140's, 180's etc, been
too long), the plain-jane knock-out plug has an internal snap ring
inside the "fingers" that shoves them "out" with a little more force
after the plug is snapped into the hole in the wing skin.

I would procur a suitable replacement knock-out plug and source a
suitably sized snap ring to put inside it. The problem is finding a
relatively thin snap ring that has a large enuff ID.

Makes it a little trickier to get it snapped into the hole (and pried
back out for that matter), but helps keep the little sucker in place...

TC