Cessna 150 Door Latch.

The exterior door latch paddle is spring loaded to
close - it opens in the "suicide" i.e. blow open direction.
The two coil springs holding the paddle closed were
made of regular steel, so they corrode and finally break.
Stainless springs are better.

It is a regular performance to remove the interior panel etc.,
to get at the latch assembly.
A NEW replacement latch assembly from a Cessna source
costs $1200 (yes you did read that right)
so you need to handle it like gold and rubies.

A hinge pin holds the paddle in place.
The pin is secured by a split pin.
The pin may freeze on the assembly casting.
If you drive it out, the paddle may be cracked.
Fortunately, Chief etc., offers a chrome die cast
approved replacement for under $20.
Placing the two springs in position needs plenty
of patience.
Finally, perhaps with a little smoothing of the lock
hooks on the paddle, the door shuts and locks and
the latch doesn't blow out into the breeze.

Brian Whatcott