H2 Air suspension checkup

[The_Mountain]

My H2's left rear corner sits about an inch or two lower than the right corner. It doesn't get lower if it sits overnight, and the compressor only runs for 10-15 seconds in the morning, and may do that once or twice more on a given day at most not counting the times it airs up after doing a 50mph+ run where the rear suspension airs down.

IOW, I don't *think* I have a bad airbag. So, am I pretty much guaranteed at this point to have a failing suspension level sensor on the left side, or is it possible I could hook up a scan tool, force the system to go through recalibration, and the truck would sit level again afterwards?

 

[The_Mountain]

In doing more research, I did find this:

From autorepairinstructions.com:

Trim Height Calibration Procedure – With Tech2 Scan tool in hand and connected, go to the air suspension section and under “Special Functions” you can find the calibration procedure, follow the instruction within the scan tool.

And then from another Hummer forum, slightly paraphrased:

I need to re-calibrate my rear air suspension. I have a tech II scan tool but all the instructions say I need Suspension Position Calibration Blocks, CH-47816. Anyone know where I can get these blocks or another way to calibrate without them?

The calibration blocks tool overall height is 5 3/16", and this distance is measured from the metal flange where the bumpstops are mounted to the corresponding bumpstop contact point on the axle.

So, in theory, you can use a jack to set the height, and then run the suspension calibration procedure. With this info in-hand, I'll see if I can borrow a scan tool and a jack, and see if that enables me to permanently correct the sag.

 

[Fish]

I haven't had that problem and I've never heard of all that calibration stuff...I replaced my bags last year because the original bags looked like they were about to give out.

If you disconnect the sensor from the suspension and manually move the sensor will it continue to air up and level out? If it does then maybe recalibration will work, if it doesn't maybe it's a bad sensor.

Just guessing here...

 

[twinmill28]

I didn't think my bags were bad because the truck only randomly dropped the suspension at odd times for no known reason. It finally got bad enough to realize the leaks started on the inside of the bag where it droops near the mounts when the truck moved up and down---so at normal ride height it seemed to hold air. Bags are amazingly simple to replace---just don't do it in the middle of summer on a 115 degree day, trust me.....