I removed my distributer from the motor to clean
it. The vacuum breaker plate should move with no
resistance. That assembly has to be removed to get
further down to the little weight-spring thingies.
Make sure they move freely. I used brake cleaner
(I think) to free it all up, and then some silicon
lubricant. Adjusted the gap while I was in there.
Make sure you start at TDC before removeing the
distributer (I assume you know that)

1984 4Runner