AIR GAUGES

Note - This is not meant to be an all-inclusive page on air gauges.

The air pressure gauges in your D are something that you need to occasionally monitor as you are cruising down the highway.   Air pressure is what supports you coach, and more importantly, stops it.   Some models have one gauge with a red and green needle and some models have two seperate gauges.   Both should register around 120 psi when you are going down the road.   You have probably noticed that one gauge or needle will go down significantly when you inflate your airbags - this is normal.   You will also notice that one gauge or needle will fluctuate a bit going down the road, particularly as you traverse bumps, while the other gauge is mostly steady.   This is normal as the front suspension uses a lot of air.   However, here are some things that are not normal that you should be aware of:

  1. If one or more of your air gauges constantly goes up and down - for no apparent reason - you may have a plugged or failed air dryer.
  2. If one of your gauges seems to suddenly become erratic, you may have water in the system or possibly a bad spitter valve.
In any event, any abnormal operation of the air gauges should be checked out by Freightliner immediately.

I think it is a good idea to occasionally get under the coach and pull the drain cables.   If more than a mist is ejected, you need to have someone look into this to determine the problem.   Freightliner says they charge big bucks to purge the system of water, and you certainly don't want water in there or you may not be able to stop!

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