Air pressure in secondary line won't go up to normal level

Could be a damaged air bag if it was ran a long distance being deflated.Might be a small tear on one of them.

 

Okay. That tells me a lot. I was wondering if running a long distance with the air bags dumped might have somehow caused the leak. Apparently, it is a possibility.

 

I just tried the test. I dumped the air bags, and the pressure in the secondary air line went up to about 124 psi, which is normal. So, apparently, my suspension has a leak.

How did you learn that test anyway?

 

Spray bottle with soapy water will help find the leak.
When was the last time air bags replaced ?

 

Common Sense.

If you were running with the bags deflated you can damage the bags, which means you need both of them replaced. You can hear the leak, so drop the trailer, move it to a quiet spot, dump the suspension, and bring it to full air where the governor trips shut the truck down then inflate the suspension. You will have to stand where they are, with a leak like that, you will hear it.

The leveling valve should also be replaced.

 

I don't know. I'm a company driver.

 

The Breakdown Dept. at my company changed the plan. Breakdown had me bobtail to a terminal to get the truck repaired instead of waiting on the repair shop at the truckstop to fix the truck. I have already dropped my truck off at the terminal, and I am on hometime at my house now.

I don't know what "bring it to full air where the governor trips shut the truck down" means. I am not aware of any governor on the truck that shut the truck's engine off if the air pressure rises to a certain level. So I am baffled. What does "bring it to full air where the governor trips shut the truck down" mean?

 

Let me go into more detail about the test than I did in post #23. I was in a hurry to drop off my truck in post #23 and drive my car to buy some merchandise at a store before the store closed. So I quit the test a bit too soon, and I did not go into enough detail.

When I dumped the air bags and idled the truck's engine, the air pressure in the secondary air line did indeed go up to 124 psi. Then I idled the truck's engine for about five minutes to see if the air pressure would hold at 124 psi. Before I even started the test, I decided I would idle the truck's engine for 5 minutes, no more and no less. For about 4 and a half minutes, the air pressure in both the primary and secondary air lines held at 124 psi. But then after 4.5 minutes, the air pressure in both the primary and secondary lines dropped to about 110 psi, which is slightly below normal. So I am not 100% sure what to think. What was most striking to me when I did this test is how the primary and secondary air lines moved in tandem as I did the test. The primary and the secondary air lines both dropped from 124 to 110 psi simultaneously. Since the air pressure in both the primary and the secondary dropped from 124 to 110 psi, I am not 100% sure that the suspension has a leak. What do you think? Does the fact that the primary and the secondary moved in tandem indicate anything about the leak?

 

I think you need to get a better understanding of the air system in the vehicle you drive.

 

Yeah. That's why I created this thread.