On Mon, 3 Nov 2014 09:16:09 -0800 (PST), Frank Thompson
If this worked before and just stopped, try putting a little oil on
the bolt. They can get dry and bind. If this never worked, look at the
strike and be sure there is a camming action when it closes.
(The ramp on the strike, hits the sloped part of the bolt)
My bet is the oil fixes it. My garage door does the same thing about
every other year if I don't lube it.
There is a chance that it might just be wear in the bolt but I am not
replacing it for 3 drops of oil