Chassis Air Pressure

[MartyQ]

Seems like it is taking longer and longer for the air pressure system to fill the air bags and for the pop off valve to pop, even at fast idle. In fact on the last start I got near max pressure BUT the pop off valve never opened. It took a short drive to get to the max pressure. Is there a spec on how long it should take to pressurize to max/normal pressure? Called Freightliner and they said call Cummings, called Cummings and they said it is a Freightliner issue. Any suggestions I should have the techs look at during next service visit would be appreciated.

[ceedog]

Are you trying to air up with the jacks up or down? Some Berk models air up quicker with the jacks down.

[Lincman983]

I would have them check out that air valve for one. It sounds like the pressure switch isn't cutting off at the limit. here is how to air up the leveling system;

HOW TO INFLATE AIR BAGS

1-START ENGINE

2-POWER ON LEVELING SYSTEM

3-HIT RETRACT ALL BUTTON

4-LET SYSTEM CYCLE

5-POWER OFF LEVELING SYSTEM

6-CHECK AND SEE IF AIR BAGS ARE INFLATED

[MartyQ]

Lincman...
That is the procedure I use. You refer to an air valve. Which one? My problem is the air pressure is not building as quickly as it did in the past. The photo you attached is associated with the ride height or something else? Thanks.

[MartyQ]

Originally Posted by ceedog

Are you trying to air up with the jacks up or down? Some Berk models air up quicker with the jacks down.

To inflate the air bags I have to retract the jacks.

[Lincman983]

Originally Posted by MartyQ

Lincman...
That is the procedure I use. You refer to an air valve. Which one? My problem is the air pressure is not building as quickly as it did in the past. The photo you attached is associated with the ride height or something else? Thanks.

The valve pictured is the auto dump valve for the air ride system. They can get sticky and will not trigger the compressor to air the bags up properly.

[ceedog]

Lincman,


Where is the valve located?

[Lincman983]

Originally Posted by ceedog

Lincman,


Where is the valve located?

Should be on the frame rail close to the air bags. It is installed on the chassis by Freightliner.

[Tony Ramirez]

Originally Posted by Lincman983

The valve pictured is the auto dump valve for the air ride system. They can get sticky and will not trigger the compressor to air the bags up properly.

Lincman, Is there something that needs to be done to keep them from getting "sticky"? And if they are sticky, what's the fix?

[Lincman983]

Originally Posted by Tony Ramirez

Lincman, Is there something that needs to be done to keep them from getting "sticky"? And if they are sticky, what's the fix?

That would probably be a question better suited for Freightliner. We don't see many issues with the chassis portion of the coach as we only do the "house" side and not the chassis, driveline and suspension components as those are installed by Freightliner.

[ceedog]

Lincman,


Copy & thanks for the info.