Hello fellow bricksters!

I'm looking for help with restoring functionality of the climate unit on my 1998 V90. The car's got 229K on the odo, and I've owned it for quite a number of years, over which the AC performance deteriorated gradually (had freon recharged a couple of times, but besides that no work done on the climate system). Besides the obvious problem (low on freon) I'm having the problem with the air flow through the vents -- it practically stops when car is accelerating, and actually the flow is not that great under regular conditions as well... I've been told by my mechanic a while ago that vacuum servos (bellows) on the climate unit are to blame, part number 9463040 according to him. I looked up what these things do, looks like 9463040 is for recirculation (underneath the unit) and there's also two of 9463041 (dashboard vents, it seems) and one of 9463042 (for diversion to floor, defroster) on the side of the unit.

I'm looking for help with actually diagnosing the problem: from what I understood from the various sources it's likely that I have a vacuum leak somewhere; rubber connectors under the hood have been replaced and one-way valves checked, where do I look next?

Also, I've checked if I can actually get the new servos -- looks like these part numbers are marked as no longer available at pretty much all online vendors -- any idea on where I may be able to get them? I'm afraid junkyard parts may suffer from same problems as mine...

I don't mind doing the work of disassembling things and getting to climate
unit -- I've got time and patience, and am no stranger to things under the dashboard in my car :-)

Also, a related question: the heating on the car seems to be working except
for the regulator (full heat when fully open, practically no heat when the temperature dial is anywhere below the max). Any idea on what may be causing this?

Since I'm this somewhat major project of getting to servos, is it worth considering replacing the heater core (19 y o car, 229K miles...)? No symptoms of heater core leakage as of yet...

Thank you all!

Vlad

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'98 965