Converting back the Z55 Air Ride Suspension

[Joseph Garcia]

After considering the various recommendations from you knowledgeable folks here in the Forum, I am going to convert back to the original Z55 air suspension on my 07 Yukon XL Denali.

I will change out the entire front strut assemblies, as I do not know the condition of all their current sub-assemblies. I will change out only the air shocks on the rear, as it looks like the springs are new, and they are the correct part number for the Z55 suspension. I will also change out the compressor, as it is 14 years old, and I do not know its current condition.

Specific suggestions/recommendations on brands/part numbers for the front struts, and air shocks for the rear, and the compressor are welcome.

Also, if anyone has a link to an exploded view of the front and rear suspension and compressor assemblies, I would welcome receiving it, as I need to determine how much the original electrical and pneumatic components and connectors were hacked up, when the previous owner converted away from the Z55 suspension. As such, I believe that I will be searching for electrical connectors and air lines and pneumatic connectors, in order to restore the Z55 suspension system. I do believe that the original height sensors and rod assemblies are still in place on all 4 wheels.

Thanks in advance.

 

[OR VietVet]

Good luck with the upcoming work to get back to stock.

 

[kbuskill]

Dorman 949-099 is the compressor I went with...

https://www.dormanproducts.com/p-101394-949-099.aspx

It has a rubber "mud flap" covering over the top as well as the bottom to help protect it from the debris slinging off the rear tire.

It also has a thermal protection switch (circuit breaker) to keep the compressor from overheating and it comes with a lifetime warranty.

 

[adventurenali92]

Dorman 949-099 is the compressor I went with...

https://www.dormanproducts.com/p-101394-949-099.aspx

It has a rubber "mud flap" covering over the top as well as the bottom to help protect it from the debris slinging off the rear tire.

It also has a thermal protection switch (circuit breaker) to keep the compressor from overheating and it comes with a lifetime warranty.

It’s funny I’ve read lots of things on the arnott and dorman compressors and how dorman parts usually aren’t the best, and to go with the arnott compressor for these rebuilds. I used the dorman compressor for my 2006 when I did all new rear Z55 suspension, the compressor has been in the truck for almost 4 years I think, and not a single problem. Works flawlessly.

 

[gooffeyguy]

I replaced my compressor back in March and went with the Dorman. Advance Auto online and shipped to me had it the cheapest, something around $175

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[kbuskill]

It’s funny I’ve read lots of things on the arnott and dorman compressors and how dorman parts usually aren’t the best, and to go with the arnott compressor for these rebuilds. I used the dorman compressor for my 2006 when I did all new rear Z55 suspension, the compressor has been in the truck for almost 4 years I think, and not a single problem. Works flawlessly.

Dorman is hit or miss, it just depends on the part.

As an example, I wouldn't trust their plastic heater hose T-connectors BUT they are the only company who makes an aluminum Y-connector for the hoses between the water pump, surge tank, and heater core... and it is a solid piece and eliminates the plastic connector in that location.

 

[adventurenali92]

Dorman is hit or miss, it just depends on the part.

As an example, I wouldn't trust their plastic heater hose T-connectors BUT they are the only company who makes an aluminum Y-connector for the hoses between the water pump, surge tank, and heater core... and it is a solid piece and eliminates the plastic connector in that location.

Yeah that’s where I’m at too. Depends on the part. Lol.

 

[91RS]

Use the OEM parts, especially for the shocks. If you're going to do all the work to put it back to stock after the previous owner hacked it up, you want it actually ride/handle like it was supposed to. I know I'm in the tiny minority here but I think Arnott is crap compared to the OEM. I've seen a number of their shocks fail in very unique ways (ways the OEM ones could not fail in because of how they're made) and they do not ride like the OEM. I would only buy Arnott for an airbag only suspension, I do not like their shocks in any way, shape, or form.

 

[George B]

Use the OEM parts, especially for the shocks. If you're going to do all the work to put it back to stock after the previous owner hacked it up, you want it actually ride/handle like it was supposed to. I know I'm in the tiny minority here but I think Arnott is crap compared to the OEM. I've seen a number of their shocks fail in very unique ways (ways the OEM ones could not fail in because of how they're made) and they do not ride like the OEM. I would only buy Arnott for an airbag only suspension, I do not like their shocks in any way, shape, or form.

Would you care to elaborate on the failures you are speaking of?

 

[gooffeyguy]

Arnott rear air shocks are rebuilt OEM

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[avalonandl]

I installed AS-2708 Arnotts rear shocks and they work perfectly, RA was VERY fast on the credit for the cores.

 

[91RS]

Would you care to elaborate on the failures you are speaking of?

Mostly failure of the airbag attachment points, the airbags didn't blow or leak out just when you lifted the truck the top mount didn't stay and was pulling tight on the wiring and air lines. I've also seen one where the upper mount to the frame came completely apart and the shock beat the hell out of the aux. heater/ac pipes and caused a leak. The rebuilt OEM ones might be ok but if you buy new then everything is new. The OEM parts lasted 10+ years, what are you really saving? Replace them once and be DONE.

 

[George B]

Mostly failure of the airbag attachment points, the airbags didn't blow or leak out just when you lifted the truck the top mount didn't stay and was pulling tight on the wiring and air lines. I've also seen one where the upper mount to the frame came completely apart and the shock beat the hell out of the aux. heater/ac pipes and caused a leak. The rebuilt OEM ones might be ok but if you buy new then everything is new. The OEM parts lasted 10+ years, what are you really saving? Replace them once and be DONE.

Good points. I have a set of the Arnott remans and am hopeful they will serve me well. Several other members here have been running them for a while too. Fingers crossed.

 

[gooffeyguy]

The front struts I would go OEM.

The rear air shocks are so easy to get to and change out quickly. The lifetime warranty on the Arnott remans won my vote.

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[adventurenali92]

I scored a set of virtually brand new rear arnott shocks and OEM front auto ride shocks for my 2006 Z55 setup from another member about two years ago, I think august makes two years they’ve been in the truck, towing, back and forth on several road trips and daily driving with all my detail gear in the back and the arnott shocks have not given any problems since. I’ll vouch for the arnotts lol.

 

[HACK BLOCK]

best place for the rears are the arnotts on RockAuto its like 200 each then u get back $50 for the core and the fronts I don't remember seeing them any cheaper than 300 each but you would need your rpo code for what springs you have to get the correct part

 

[HACK BLOCK]

best place for the rears are the arnotts on RockAuto its like 200 each then u get back $50 for the core and the fronts I don't remember seeing them any cheaper than 300 each but you would need your rpo code for what springs you have to get the correct part

and the only 2 companies that sell the correct one are acdelco and Monroe. arnott doesn't make z55 front shocks. they are all conversions

 

[George B]

What progress have you made @Joseph Garcia?

 

[Shmel de Tex]

I used AC Delco for the front and Monroe for the back. One of the front AC Delco leaked and had to be replaced under warranty. No complaints about Monroe.

 

[Joseph Garcia]

What progress have you made @Joseph Garcia?

Still researching my options and associated costs.

At this point, however, I am leaning toward restoring only the auto-leveling portion of the Z55 suspension by using air shocks in the rear, as the total cost to fully restore the full Z55 suspension (electronic and air), using GM OEM parts, including front struts, rear air shocks, compressor, and control module, will probably exceed $3500, and this assumes that the height rods and wheel sensors are all still on the truck and fully operational. I simply cannot justify spending that amount of money on this truck for this specific work, as I do not believe that the incremental improved handling from the electronic portion of the Z55 suspension would be worth the incremental level of investment to include it.

For restoring the auto-leveling by replacing the front strut assemblies with new strut assemblies and replacing the current coil-over rear shocks with rear air shocks, and a new compressor and control module, I am currently looking at front strut assemblies by Arnott SK-2954, the rear air shocks by Arnott AS-3430, and the compressor by Arnott P-3430, and the control module by ACDelco 15095294. This can be accomplished for less than $1500. And, perhaps, I won't need to replace my existing control module.

I'm still researching and evaluating, but this is where my current mindset is.