My air springs [88 blass]work great in very cold weather ,if the car is in a heated garage overnight. But if it sits out side for a few days at -25 or colder ,the car will gradually sink down [probably from a small air leak] At these temeratures the compressor will not pump up the springs,untill I drive it for about 1/2 an hour.
I just replaced the rear bags and solenoids but not the comperessor and dryer.
Could I have moisture in the bags causing them to freeze rock solid .
Does anyone have experience with this suspension in extreme cold conditions...

I've had that happen in the extreme cold where they wouldn't even fill up. It just sat low for a couple of days and one day it came back to life when it warmed up

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Does anyone have experience with this suspension in extreme cold conditions...
Yes. You have moisture inthe system and need to remove it by renewing or replacing your dryer.

See: http://www.thelincolnmarkviiclub.org/tech/airDryer.pdf