where to find nylon fasteners for hvac intake vent?

[hpcbmw]

My house has an hvac system, probably installed in the 1980's.  The air intake vent in the ceiling has two nylon fasteners that you turn to open the vent door and change the air filter. The fasteners are about 1/4" square. When you turn the notch in the fastener, it twists open a pair of nylon fingers that open up enough to hold the vent door shut. Does this make any sense????

Anyway, the fasteners broke and now I can't keep my intake vent door closed without duct tape. Anyone have any ideas on where to find these fasteners? I've checked Home Depot, Ace Hardware, Orchard Supply and the local appliance parts place with no luck.

[appl.tech.29501]

I know what you talking about, but not sure where or if you can even buy them. Maybe one of the HVAC guys knows a special name for them. If all else fails you could just mount a pair of small slide blots to the door.

[ACtechGUY]

I would just zip in a couple of self tapping screws. That would fix it real good. Or you could just buy and install a new return air grill.