front air pressure

[motofamily]

While traveling the last couple of days i noticed the front air pressure on my air gauge cycling every 5-8 miles it would drop to 100psi or so and then climb back up to 125psi or so i dont know if this is normal or not and if its not normal any idea what to look for?

2006 freightliner chassis and cummins 300 isb

[akadeadeye]

Don't check your pressure so often. The only meaningful reading is when you have not driven it over night. In other words, check it cold. Hot tires will read higher pressure. Never let air out of a hot tire. You will be under inflated if you do.

Don

[motofamily]

Not in the tires the front air bags/gauge reading on the dash

[siggyd]

IMHO, this is not normal,you seem to have a leak somewhere. After stopping,listen for some hissing to find the leak.
You can also look at the gauges after stopping for 15 min. or 1/2 hour and see if there is a big difference between the gauges.

[1ciderdog]

I have not noticed air pressure drop on mine. As far as I can remember it stays at 125 once it has built up the air pressure.
Safe Travels
Bob

[motofamily]

Siggyd it sat overnight and all day by this afternoon the driver side front looks lower to me i did here some hissing from the front left when my wife was inside the rv getting some stuff out other than that no other sound

[cbeierl]

The front air tank supplies the air suspension, so if you're on a twisty road that's causing lots of work for the suspension that could explain what you're seeing.

[motofamily]

I was on 95

[siggyd]

Look at the gauges with IGNITION ON but do not start the engine after some time!
Siggy D.

[MaverickBBD]

I know when you look underneath your coach it looks like you have two tanks. You really have Five tanks. Primary (usually the "front" gauge), Secondary (usually the "rear" gauge) a wet tank, a ping tank that takes air to and from air bags and another I can recall off hand. If you need to know you can call 1.800.FTL.HELP. Somewhere in all the air movement and 'making' there is a fluctuation. I should be checked out. It may take alot of crawling around with soapy water to rule out a leak. That would be my first step.

[motofamily]

We were towing a car trailer would this have anything to do with it maybe effecting the ride wich made the air cycle more or maybe i need to change my air dryer filter

[Skip426]

Quote:

Originally Posted by motofamily We were towing a car trailer would this have anything to do with it maybe effecting the ride wich made the air cycle more or maybe i need to change my air dryer filter

Air dryer filter, should be serviced regularly, 3years/50,000miles, but trouble with the filter should effect both tanks/gauges. When you talk to Freightliner Help Line , get them to send you an air system diagram, to show you all the systems that run off the front tank. The tank may also feed the air suspension, engine brake,& air horn, any of these systems could account for the air pressure drop through, system use of air or leakage. but as in other posts, any leakage should be audible with the coach stopped & parked ,with no one inside to trigger the air levelers. If you are looking for a leak yourself, wear eye protection and gloves.
Good luck

[MaverickBBD]

When you tow, do you use air for the toad supplemental braking system? Although FL supplies a customer air manifold, it wasn't until recently they accepted the fact that people use it to air their toad brakes. Prior it was an instant warranty violation.

[Luckiest Dre]

Movement in the air pressure is normal. There is an allowable amount that is considered safe. If your compressor cannot keep up with the air loss (usage) service is needed. The loss can be determined by starting your engine and building the pressure to the top pressure your gauge is set to. Turn the ignition off and start pumping the brakes with the yellow button pushed in . At some point around 60 PSI the button should pop out. At that time watch your second hand on your watch. There is an allowable time set by law that the compressor will take to rebuild the air. If yours does not respond to that timetable it is time to have it serviced. That time should be easily found by reading the rules printed for the air brake system required to obtain a CDL liscense.