Service brake problems in wet weather

[dalexis]

Hey guys sorry to bring this post back but still having problems with the brakes. It rained really hard today for the first time in a while and the brake problem reared its head again. Brake pedal felt like a brick and had to use the trailer brake valve to slow truck.

I found a service bulletin 42-69 excessive moisture in the air system but the truck is not having any of the symptoms it describes. This "ONLY" happens when it rains really hard and there is no error code.

Found a post on another forum about the rain trough under the windshield leaking down onto the compressor. Kind of leaning in that direction. Was thinking of maybe taking a couple gallons of water and try to replicate the heavy rain to see if it is in fact leaking onto the compressor. This is on a 2016 freightliner cascadia.

Thoughts?