Weird air suspension problem, any ideas?

Kuda

Registered
My usually trouble-free '97 LSC finally crossed the 100K mile marker this year (purchased in 2004 from the then-president of the National Lincoln Owner's Club). The all original suspension started sagging in the back over night, and the air ride suspension light occasionally came on. No big deal thought I, it's been a good 100K so it needs some love. Got all 4 new bags, new dryer, new compressor, new solenoids, and for good measure, new rear shocks, and had the local garage install everything. Seemed to go well for about 2-3 days, then had *exactly* the same issue: dropped in rear, light comes on intermittently and, when it does, the compressor doesn't kick on. Completely random too, no forecasting when it will work and when it won't. After chasing their tails for a couple of weeks, I picked it up from the local garage and took it to a local Lincoln dealership. The told me their computers wouldn't communicate with the suspension module (obsolete of course), so I tracked down and purchased a known good used module (TBSCShop) and shipped it to the dealership. Once installed...same exact issue. AND now they're telling me it wasn't the module, they just don't have the equipment to communicate with a car this old. After tossing over $2800 into the suspension to get it working, I'm at a loss now. I'm not interested in converting to springs, I'd really like to restore it back to it's former glory. Any ideas, or places in the Baltimore MD/Tri-state area that have the expertise to diagnose and really fix this issue? Any help is very much appreciated!
 

driller

El Presidente
Staff member
Paid Member
If it were me, I would suspect the air suspension relay. It sounds like the suspension could be triggering to energize the compressor but the solid state relay fails to do its job.

A quick validation test would be to catch the suspension system when it does properly inflate the suspension to normal height and shut off the air suspension switch in the trunk. This will prevent the system from activating to vent or fill the airbags and effectively determine if there is a leak that needs to be tended to. If the suspension stays up overnight (or during a short drive) withe the switch off, you can be reasonably assured there are no leaks causing any issues.

The relay is mounted to the inner passenger fender well behind the wheel liner near the suspension compressor. Last I looked, they were still readily available as they were used on many Lincolns besides the Mark VIII's.
 

Kuda

Registered
If it were me, I would suspect the air suspension relay. It sounds like the suspension could be triggering to energize the compressor but the solid state relay fails to do its job.

A quick validation test would be to catch the suspension system when it does properly inflate the suspension to normal height and shut off the air suspension switch in the trunk. This will prevent the system from activating to vent or fill the airbags and effectively determine if there is a leak that needs to be tended to. If the suspension stays up overnight (or during a short drive) withe the switch off, you can be reasonably assured there are no leaks causing any issues.

The relay is mounted to the inner passenger fender well behind the wheel liner near the suspension compressor. Last I looked, they were still readily available as they were used on many Lincolns besides the Mark VIII's.
Excellent tip! I'm going to give that a shot (turning off the switch). I'll also replace the relay, just in case. Thanks again!
 

Daddy'sRod1997

Registered
My usually trouble-free '97 LSC finally crossed the 100K mile marker this year (purchased in 2004 from the then-president of the National Lincoln Owner's Club). The all original suspension started sagging in the back over night, and the air ride suspension light occasionally came on. No big deal thought I, it's been a good 100K so it needs some love. Got all 4 new bags, new dryer, new compressor, new solenoids, and for good measure, new rear shocks, and had the local garage install everything. Seemed to go well for about 2-3 days, then had *exactly* the same issue: dropped in rear, light comes on intermittently and, when it does, the compressor doesn't kick on. Completely random too, no forecasting when it will work and when it won't. After chasing their tails for a couple of weeks, I picked it up from the local garage and took it to a local Lincoln dealership. The told me their computers wouldn't communicate with the suspension module (obsolete of course), so I tracked down and purchased a known good used module (TBSCShop) and shipped it to the dealership. Once installed...same exact issue. AND now they're telling me it wasn't the module, they just don't have the equipment to communicate with a car this old. After tossing over $2800 into the suspension to get it working, I'm at a loss now. I'm not interested in converting to springs, I'd really like to restore it back to it's former glory. Any ideas, or places in the Baltimore MD/Tri-state area that have the expertise to diagnose and really fix this issue? Any help is very much appreciated!
Hey Cuda, I just went through the very same dilemma as you this past week! However I brought my (97 LSC) chariot to my mechanic and told him my rear end dropped and became an instant Low-Rider, anyway he did the soap and bubbles test and found that the air bags were dry rotted, cracked and leaking. The right one was the worst out of the two, (But not too bad for a 24 year run). So I did some research and found a company by the name of X2 industries that has a wide selection of after market and OEM air ride systems going all the way back to "61" Continentals. I purchased a pair of air bags at the price of $273.00 flat no tax & free shipping! So after a week of diagnoses and trial and error my mechanic went through the schematics and found that the culprit was the rear sensor, so he thought! but it turned out to be faulty pins (5 pins) in the connector. So $500.00 + air bags later....

So the the moral to the story; check the little items that often go overlooked.

Peace from the the East! and have a good one!

P.S. I'm on L.I. N.Y.
 

Daddy'sRod1997

Registered
Hey Kuda, I just went through the very same dilemma as you this past week! However I brought my (97 LSC) chariot to my mechanic and told him my rear end dropped and became an instant Low-Rider, anyway he did the soap and bubbles test and found that the air bags were dry rotted, cracked and leaking. The right one was the worst out of the two, (But not too bad for a 24 year run). So I did some research and found a company by the name of X2 industries that has a wide selection of after market and OEM air ride systems going all the way back to "61" Continentals. I purchased a pair of air bags at the price of $273.00 flat no tax & free shipping! So after a week of diagnoses and trial and error my mechanic went through the schematics and found that the culprit was the rear sensor, so he thought! but it turned out to be faulty pins (5 pins) in the connector. So $500.00 + air bags later....

So the the moral to the story; check the little items that often go overlooked.

Peace from the the East! and have a good one!

P.S. I'm on L.I. N.Y.
 

billcu

Head Moderator
Staff member
Here's a link to electrically testing the compressor, solenoids, and vent valve if you're good with electrickery. If that all checks out and you replaced the airsprings and compressor, you might have a leak at one of the fittings. You could test for leaks by opening the solenoids one at a time, and running the compressor and have someone else check at the compressor and solenoids for leaks. I recently ran into this when changing out a compressor, one of the airlines wasn't fully pushed into the push to connect fittings, you can feel it leaking when the compressor is running.
Here's the link:
 
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