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Curtis B.
Curtis B., Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 27078
Experience:  Technician turned service manager on multiple lines of trucks and engines, used in industry.
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I have a 2007 kenworth t800. I won't build air pressure in

Customer Question

Hello
I have a 2007 kenworth t800.
I won't build air pressure in tanks. But the pop off valve keeps popping off every 15 seconds.
Compressor pumps fine.
What could be the problem?
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Curtis B. replied 1 year ago.

Pop off valve. as in the air dryer popoff? If so, the air dryer release valve is bad. For test remove the valve or plug the hole.

Customer: replied 1 year ago.
What is the air dryer release valve and where is it located?
Expert:  Curtis B. replied 1 year ago.

The valve in the bottom of the air dryer.

Expert:  Curtis B. replied 1 year ago.

where is the valve that is popping off?

Customer: replied 1 year ago.
Bottom of air dryer.
That valve is new just replaced a couple weeks ago.
Expert:  Curtis B. replied 1 year ago.

The out line of the air dryer, goes to air tank. There will be a check valve in this line, usually right at the tank. Could the pressure be building in the air dryer and check valve stuck, keeping air from tank?

Customer: replied 1 year ago.
Ok
So there is no air coming out of the 2 out lines going to tank. I removed lines at the dryer.
Expert:  Curtis B. replied 1 year ago.

Is there pressure to the dryer?

Expert:  Curtis B. replied 1 year ago.

If there is pressure to the dryer, the dryer is plugged, bypass the dryer and see if air will come up.

Customer: replied 1 year ago.
there is pressure to the dryer.
How do you bypass dryer?
Expert:  Curtis B. replied 1 year ago.

Take the inlet line from compresser going to the dryer, and take it direct to the outlet from dryer. May have to use a tee to connect both outlets.

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