: How does ELC work?

02-13-12, 12:16 AM
I've searched and searched but didn't get a direct answer.

I drive a 1999 Cadillac Deville base model with about 120,000 miles on it. I've been having problems with the ELC system. Well I know my compressor works because when I first start up the car it turns on and airs up the shocks in the back. It levels out the Deville that ONE time until I turn off the car and start it again. In the meantime it'll lose air and the back will start to sag. Or I'll start the car and have passengers in the backseat it'll level out and by the time I get to my destination the back end will be low.

Well I figured the shocks were old and needed replacing so I opt to replace them with Gabriel model# G56664. Well I get them installed and I start the car and they air up faster than with the old shocks. Go for a test drive and things are smooth once again. So I thought problem was solved. After a few days the same problem starts to happen again. It airs up when I start in the morning, levels out, I get to work, park and then when it's lunchtime the back end is low again. The ride is smooth and the back end levels out maybe 75 percent of the time.

So I'm wondering how does the ELC work. Does it air up and hold air?? Or does it air up and hold air while I drive around and then release the air while the car is sitting?? I haven't been able to do the soap water test since the weather has been wet and cold. It's just been bugging me that the end still sags. I was talking with a friend of mine and he suggested I bypass the compressor and just add new lines to the shocks and air it up manually with a valve installed like the ones on a tire. Sounds like a good idea to me, has anyone attempted this??

Any thoughts/ideas/recommendations would be greatly appreciated.

02-13-12, 09:00 AM
ELC is supposed to compensate for extra loads in the trunk and/or rear seat. The rear should stay level or just a tad raked under all conditions at all times.

There are one or two height sensors, in one or both rear wheelwells, attached by a ball joint rod to the lower suspension arm(s). They feed signals to the system and compressor, which has a solenoid controlled pressure supply/release head. Included in the compressor assembly is a dessicant filter/dryer canister. This is a service item and is supposed to prevent condensation moisture from corroding the compressor (it eventually gets saturated and the compressor or head dies).

So - you get into the car and turn the key ON. About 8 seconds later the compressor runs for a second or so to preload the shock bladders and do a sequence prove-out. After that the compressor should only need to respond to load changes - the shock bladders stay loaded at all times. To completely test the system, get two assistants. Pop the trunk. You turn the Key ON - does the system do the pre-charge ? OK. Now all 3 of you sit on the open trunk lip. Does the compressor run and level the car ? If so, good........now all 3 hop off and you listen in the RR wheelwell for hissing air as the system once again levels the car by venting off the shock bladders. If all this works and the car still settles overnight, then you have a slow bladder, air line (most likely) or compressor head leak.

To find a leak get the car up on a lift and use a spray bottle of dish liquid soap solution to wet the lines and bladders - bubbles = leak.

Talk to Chris in Parts at Rippy Cadillac over there >>>>

02-14-12, 10:10 PM
EDIT: - moved my question to DeVille forum

02-16-12, 09:37 PM
Where can I source the air lines at? The dealership parts house told me that the lines were discontinued. Ordering parts online has been a real drag since I have to wait for them to arrive, install and then sometimes I get defective parts and the whole return is a real pain.. more waiting.

Is there a way I can bypass the factory lines, factory compressor/drier and manually air up the shocks?? I stopped by Oreilly's and asked for an airline kit and the guy was quick to say that it wouldn't be compatible with my shocks.

Thanks for hearing me out. :D

02-16-12, 11:39 PM
Dig into the AirLift site. They have been making every kind of air suspension parts for at least 60 years. Used their products in three mid-60's GM midbody cars.

www.airliftcompany.com (http://www.airliftcompany.com)

02-27-12, 03:36 AM
After searching around I found an airline kit AK 29. Napa had to order it for me. What is in the box is two six foot lengths of air shock hose with the factory shock fittings with clips on it and the other ends are compression type fitting that go into a T with a tire valve stem on it. Well I installed it and it worked, I could manually fill the shocks but man the passenger side was leaking air! I used soap and water and it was bubbling like crazy. I learned a thing about the factory fittings on the shock too. They have two O-rings on it and you use the L shaped plastic boot to press them on the shock and then you put the clip in place and it holds everything together. I had a friend install them for me and when I was disconnecting them to install the new lines, the factory clips were sliding back and forth. But after I figured out how you install them they DON'T slide back and forth and they are secure once the clip is in place.

So I'm wondering now if I could replace the O-rings on the lines from the compressor? Because the O-rings on the AK 29 kit are more robust than the factory ones and I'm thinking maybe that was part of the leak I was having with my ELC system. Well I'm pissed that one of the new Gabriel shocks I just bought is leaking. It's a pain to order online then have to return them. :rant2:

Hope this helps anyone out there.