I was wondering if ride height can decrease due to weak coil springs? The vehical is 11 years old and is currently using the original struts and springs. Does anybody have a good point to measure from and or know what the factory spec's call for?

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LocoWBL

Springs will sag over time, yes. Are you having issues? I don't really think there is a factory height "spec", they just used certain springs.

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Bye Bye:

RIP sandrock

1. Park the vehicle on level ground.
2. Inspect the tire pressure. Ensure that all tires are inflated to the proper pressure.
3. Inspect the fuel level. Verify that the fuel tank is full.
4. Ensure that there is no extra weight in the passenger compartment or the trunk. The trunk must be empty except for the spare tire and the jack.
5. On vehicles equipped with Electronic Level Control (ELC) , ensure that the ELC is operating properly.
6. Place the front seat in the rear position.
7. Bounce the vehicle three times at the front and at the rear in order to normalize the suspension.

8. Measure the distance between the lowest point on the ball joint housing and the centerline of the control arm bolt. This distance (3) should be 30 - 50 mm (1 3/16 to 2 inch).

9. Measure the distance from the bottom of the control arm wheel bearing face to the centerline of the outboard control arm bolt. This distance (2) should be 76 - 96 mm (3 - 3 3/4 inch).

10. Measure the distance (1) from the ground (2) to the front underbody points (4). This distance (1) should be 164 - 184 mm (6 7/16 to 7 1/4 inch).

11. Measure the distance (1) from the ground (2) to the rear underbody points (4). This distance (1) 213 - 233 mm (8 3/8 to 9 3/16 inch).
12. The maximum variation side-to-side and front-to-rear is 19 mm (3/4 inch).

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*Gone, but not forgotten* - Black 2000 SSEi, HIR Headlights, Angel Eyes fogs, 3rd brake light overlay, hi-flo cat, 180 degree thermostat, HS 1.9 rockers, LSx yellow springs, Intense FWI, PCM, shift kit, push rods, and 3.4 Pulley. ZZP Power Log.

It seams lower because the floor jack use to slide under the k-frame when I would be raising the vehicle now hits the bottom edge of the k-frame. Even my wife has asked if it's sitting lower and she almost never notices any change in vehicle ride, performance ect.

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LocoWBL

Looking into the ride height I found that unbeknownst to me that there are air shocks in the rear of the vehicle. We purchased it new so they must be factory equipped but I’ve never seen the fill point. Where is this located?

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LocoWBL

The air in the rear shocks is controlled by the auto level sensor/compressor. There is a sensor that tests the ride height and sparks up the compressor as required. I'm not sure where the compressor is located but I would imagine you could trace the air lines to it. On my '03 the compressor kicks on about 15 seconds after it's started and runs maybe 10 seconds depending on the load in the trunk. You should be able to hear the compressor run if you have someone start it and stand at the back - I can hear it from the driver's seat.

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Kurt
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'03 Bonneville SE
'07 Yukon XL
'00 K2500 Crew

Maybe that was what I was assuming to be the fuel pump all this time.

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LocoWBL

How can the auto leveling system be checked to verify that it is performing correctly?

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LocoWBL

Turn the key to run (without cranking) after about 10 seconds the compressor should kick on and run fora short time then shut off

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2000 ssei gone but not forgotten

Current fleet:
2009 G8 v6, 2009 Avalanche LTZ, 2013 Volt

Sometimes while the vehicle is running but I’m stopped I hear it run for about 30 seconds. This seams to occur most often when I’ve been at highway speed and slowdown or stop. It’s hard to pin down being it’s an intermittent noise and it’s coming from behind me. I’m still wondering if I’m confusing it with a fuel pump starting to fail.

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LocoWBL

If the fuel pump stops when the car is running, the car will stop too. So you likely are not hearing the fuel pump.

The compressor is located in the fender area behind the passenger side rear tire. When you turn the key to on, it should take 30 to 45 seconds for the compressor to turn on and will run for 5 to 10 seconds. The fuel pump will turn on immediately, and just run for a few seconds.

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*Gone, but not forgotten* - Black 2000 SSEi, HIR Headlights, Angel Eyes fogs, 3rd brake light overlay, hi-flo cat, 180 degree thermostat, HS 1.9 rockers, LSx yellow springs, Intense FWI, PCM, shift kit, push rods, and 3.4 Pulley. ZZP Power Log.

I don't ever think I've heard the compressor on my car run that long. I think it cycles for a certain amount of time and turns off if the programmed ride height is not achieved. Maybe your air lines are leaking or the seals in the shocks are worn and they won't pressure up any more.

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Kurt
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'03 Bonneville SE
'07 Yukon XL
'00 K2500 Crew

I was thinking the same thing regarding the seals on the shocks.

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LocoWBL