Vacuum motor grommet

My 70 Dart has the vacuum controls for ac/heater. I was wondering if anyone knows where to get the right grommet for the vacuum motor by the heater box. Mine ripped years ago and I put in a grommet from the hardware store that was loose. Then I sleeved the pushrod with a plastic drip hose to take up the slack. Doesn't work that great. I have to reach down and wiggle the rod to get it to move. I've looked around but gave up.