So I think I have a leaking rear suspension on the left of my ‘18 Armada SL 4x4. When driving it lifts and rides fine, however after sitting for an hour or so the sag is very noticeable, a couple of inches, and it’s only the left side of the vehicle. I’ve searched online and haven’t found any solutions. Maybe I haven’t looked in the right place, but would love to hear from someone if they’ve had this issue before. Next weekend I plan to put it on stands and take the wheel off with soapy water to see if I can’t locate any bubbles to help better identify the issue. I know taking it to the dealer would cost hundreds of dollars so I rather save the bucks and fix it myself. I’ll be sure to take photos and keep this post updated when the issue is solved. Thanks in advance for any help!
If the compressor is coming on everyday, it most definitely has a leak; and if it sags after sitting for an hour, it is. My compressor comes on maybe once every 2 weeks.
If not the dealership, find a reputable shop that utilizes a full range scan tool and have them scan the truck. A pocket scanner like those used at the local auto parts store won't be able to diagnose or read "C" related DTCs. You can also spray some soap+water on the air line connections on the shocks and air compressor to rule out any leaks.
Thanks for the tips. I believe the compressor kicks on daily, honestly haven’t noticed here recently. I’ve done a bit more digging and I’ve read on a few threads how the height should be between 35 and 36 from bottom center of tire to center of wheel well. After a long drive I checked tire pressure and set all to 35psi and measured each tire, ground to top of wheel well. On the front I have 35 3/4 both left and right, on the rear right I have 36 1/4 and the rear left I have 34 5/8. It took maybe 5mins to check tire pressure, doubt enough to drop 3/4” for a small leak. I drove for about 35mins so ample time for compressor to do its job. I’ve read of a rear height sensor, I assume that adjusts both sides. Kind of curious if there is an adjustment for each side. I planned on this weekend to jack it up and check for leaks but I completely forgot it’s Memorial Day weekend and have family coming over for the weekend so I’ll have to postpone. I’ll continue to dig little by little and post until this problem is resolved. Any recommendations on a scan tool for around $500 that can read advanced diagnostic codes? Been wanting to grab one for a while but haven’t had an excuse to tell the wife why it’s needed until now.
There is only one pump and one ride level switch (on driver rear, rear control arm spring bucket) that determines and sets the air pressure on the shocks as a pair.
Having one side lower than the other suggests a leak in the line to that side's shock or the air "bag" of the shock.
Other things i've ran into that could also be a cause:
If you live in the rust belt, your driver rear, front control arm could have rusted the shock mount clean/partially off or the entire arm blown out like a jiffy pop. So just the spring is holding up that side.
The driver rear , rear control arm spring bucket could have rusted out and is sagging