My Volvo mechanic threw in the towel after replacing the brake booster with one of his own (not tested) and failed to fix the problem. He is a big disappointment after doing an excellent job of fixing a universal joint problem a few years ago.
We took back the car and I located a brake repair service in Portland Oregon. I removed the unit and shipped it off for repair. They received it last Thursday and in a quick check found it did not hold a vacuum. They will rebuild it and ship it back to me for a reasonable cost.
I am also disappointed in the Volvo company reply to my query about brake boosters on a 144 1969 Volvo. They told me from the N.A. office that this car did not have a repairable brake booster. The people in Portland contradicted that by saying there were some units in that year that were indeed repairable. Evidently, Bendix made the original units and sold it to Volvo through an intermediary company. If I had listened to the official volvo answer, I would have given up on the car. There are a fair number of these Bendix units around, so if my unit had turned out to be unrepairable, they could have replaced it with one that was.
I should be getting the repaired brake booster back next week, and I will report on how workable it turns out.
Sherwin