New Z55 autoride rear shocks - caution note

[Geotrash]

Over the weekend I installed new rear OEM shocks on our 2012 Denali because the left side was leaking hydraulic fluid pretty badly. Installation of the new ones was a breeze, with one caveat: one of the airbags rolled over on itself, even though I let the truck down gently, preventing the airbag from pressurizing with air. (see before and after pics below). The solution was to jack up the left side from the frame, causing the left rear shock to fully extend, then turn the ignition key to on, causing the compressor to turn on with its self check routine. I could hear the airbag plump up, and then let the truck back down.

Glad I noticed it, but wanted to mention it here in a thread for others to run across in their searches, lest they end up with a premature airbag failure on a brand new shock, or don't get the ride quality they were expecting.

Cheers,
Dave

Before:




After:

 

[Doubeleive]

I take it you must have replaced the shocks with the vehicle jacked up instead of on ramps so it sits at normal level?

rear shocks should be done with vehicle at rest
front shocks you will want to jack it up
rear sway bar should be done with vehicle at rest
front sway bar you will want to jack it up

the vehicle dynamics are different front & rear

 

[Geotrash]

I take it you must have replaced the shocks with the vehicle jacked up instead of on ramps so it sits at normal level?

rear shocks should be done with vehicle at rest
front shocks you will want to jack it up
rear sway bar should be done with vehicle at rest
front sway bar you will want to jack it up

the vehicle dynamics are different front & rear

That's right, but I followed the steps in the service manual, which is what I suspect others are also likely to do. The service manual says to raise the rear of the vehicle and support with jack stands on the frame rails.

That said, I also raised and lowered the vehicle with a jack placed under the rear differential and initially just placed the jack stands under the frame rails for safety without resting the weight of the vehicle on them. I removed the wheels and also loosened the shock mounting bolts but could not remove them until I'd shifted almost all of the weight of the vehicle onto the jack stands under the frame rails, thus extending the shocks. Similarly with reassembly, I didn't have enough arm strength to compress the shock and put it into place with the weight on the differential instead of the frame rails.

Cheers,
Dave

 

[Doubeleive]

I just looked at the gm service manual it does say to do a whole bunch of unnecessary stuff, lol
and I may have done it the same way i have done too much other stuff to remember exactly, I don't remember if I took the wheels off or not

 

[Geotrash]

I just looked at the gm service manual it does say to do a whole bunch of unnecessary stuff, lol
and I may have done it the same way i have done too much other stuff to remember exactly, I don't remember if I took the wheels off or not

LoL. I'd need to be a contortionist to do it with the wheels still on. But I'm built more like a grizzly bear, so off came the wheels.