We now have three 200 series Volvos -- an '85, an '87, & an '89. I'm learning a lot from reading the Board and repairing these. Would those of you with more experience give me an idea of the service life that can be reasonably expected from certain components:
-- Idle air control valve. I disassembled the one from the '85, w 228K miles, and found that it had craters in each of the 3 armature poles. The symptom was high idle speed, and was cured by using a known good one from the '87.
-- Ignition coil (In my experience, motorcycle coils tend to get weak after 20 years)
-- U-joints

Other questions for you old hands:

Why would the degree of brake boost be different in each of these 3 cars? Oddly, the newest one requires the most pedal pressure, and the old '85 the least.

The steering mechanism on the '85 has a little friction when rolling straight down the road, requiring more steering input corrections than the other cars. What should I check, and how?

Thanks for sharing! I visit the Board every day.
--Phil Loizeaux