Air Bag Problem

mkirsch wrote:
Shocks only dampen the bouncing from hitting potholes and such.

SPRINGS hold up the rear end of the truck.

What you need to do is get under there and LOOK when the truck is sagging. Most likely you will find bent or broken springs.

Take the truck to a spring shop. They will diagnose and resolve the problem.

This^^^^^^^

Shocks only dampen the bouncing from hitting potholes and such.

SPRINGS hold up the rear end of the truck.

What you need to do is get under there and LOOK when the truck is sagging. Most likely you will find bent or broken springs.

Take the truck to a spring shop. They will diagnose and resolve the problem.

Is it possible that the original owner lowered the rear of the truck to tow a 5th wheel and used the bags to control the weight. I've read many times about guys complaining that the truck is too tall in the rear for thier 5er and are told to lower the rear suspension then install air bags to level it out once loaded.
Agree need more info on truck.

OP, presume you don’t mean factory air ride, because you mention a gauge which the OE systems do not have and you can’t “pump them up” unless the system has been hacked into.
Assuming aftermarket bags and a (relatively) light/ no additional load in the truck, your post makes zero sense.
30psi, much less 50 or 90 will Jack the back of the truck up sky high.
Zero psi should result in normal operation.
So unless the springs are totally shot ( still not the issue as 90psi and NO springs at all would Jack the truck up ), you must mean aftermarket air ride like a Kelderman system or similar? (But you analysis still doesn’t make sense.)
And shocks have virtually nothing to do with ride height. They don’t support any appreciable load.

You n the son should take a good look at the truck and do a little research. Whatever the issue, it will be obvious once you spend a few minutes understanding the rear suspension.

2013 RAM??? Little more info plz.

I agree that shocks are not the issue unless they are seriously binding internally but then you would have a very rough ride. The air bags aren't the issue either, they only lift the truck and if it takes 90psi to get the truck back to where it should be with factory suspension and no load then the factory suspension has failed or has been altered.

It comes down to broken springs, hangers etc. Or, the truck was lowered intentionally and the air bags were added to keep it from bottoming out under load. You might want to find a similar truck and compare the suspensions.

If the truck is sagging the shocks aren’t the root cause of the issue. Bent/damaged /fatigued springs would explain a sagging issue. If the truck goes down the road and continually bounces/oscillates up and down that is a shock issue.

I just went through this with my 2013 Ram 3500. The bags on my truck were aftermarket not factory and because I have had some in older model trucks, I knew they were probably Firestone. I do not have an onboard compressor. If you have an onboard compressor it will complicate a bit to rundown the leak. Get soapy water in a spray bottle like you do to test for propane leaks for your BBQ. Run pressure into the suspension system either max with out a load, or halfway and connect a trailer on it for some weight. Get underneath and spray your fittings and look for the air bubbles. Mine was at the inflation valve fitting. Went to Michigan Truck .Com to buy new valve and changed it out. Problem solved.

There is a leak somewhere. You didn't say if it was factory air bags, but I'm assuming it is based on the sagging. For aftermarket bags, the shocks/existing springs should maintain the ride height unless they were removed. A spray bottle of soapy water should let you find the leak pretty quickly.

Wether they are independent of each other depends on how the were installed. Proprely they should be tied together.
Most importantly is what the heck an unladen truck is sagging for? Start by putting on proper new shocks. If they do not get and keep it back up where it belongs, then you have another problem. Do you know the history of this truck, how it was used? I suppose that it is possible that someone destroyed the springs,the mere fact that the air bags exist point towards overloading and abuse.
I installed these on my '13 instead of bags.https://www.tuftruck.com/product/ttc-1211-rear-suspension-coil-spring-kit/ In one step I increased the capability if not the RATING of my truck