: 1999 Deville Rear Sagging

07-29-11, 10:00 PM
Hey guys, this thing has me scratching my head.

After much research on this board, i cant figure why the rear of the car sits at least 2 inches too low. we initially lifted the vehicle and sprayed soapy water on everything. The passenger side air shock was leaking, so we replaced it with a new delco unit. the compressor works fine, it turns on with the car for about 30 seconds although the two lines that lead to the air filter had rotted away, they were replaced as well.
The ride height sensor was also checked out and seems to be working. We disconnected it from the lever and swung the arm up and the air bags filled up. We lowered the vehicle and voila, it was at the correct ride height, although the ride was a bit rough.
This was only done for testing around the block. Shocks arent supposed to determine ride height so the only conclusion i get to are the springs. And the ride height sensor a close second in line.

New delco front struts are here and will be installed tomorrow. I also have a replacement set of rear springs from MOOG.

Zero codes on the dash, even the history. And the only difference from now and and when one of the rear shocks was leaking was i would actually feel the car bottom out with a load on the rear and hitting a bump. No i dont, i actually feel some suspension travel. I was reading through ALLDATA and the shocks have a disclaimer that they max out @ 7 PSI, this is what lead me to believe it was the springs.

Anyone have any ideas?

07-30-11, 10:16 AM
It's either the rear springs OR you can go to a Cadillac dealer and pay for an Electronic Level Control height calibration. They use a GM Tech-II programer/diagnostic setup and it does a reset of the rear ride height.

My ELC compressor sequence is: Key ON, 10 seconds later the compressor runs for a second or so to prove out and preload, then it only runs again if a load is placed in the trunk or rear seat. It does not, ever, run for 30 seconds.

2002 Cadillac STS - (all the personal car info is missing from our profiles ^^^)