MarksMarq

I’ve been through about this forum and found only a couple of questions about air springs so here’s my question—
94 Grand Marquis with 35,000 miles and air springs sits about 1” lower on the right rear side than the left. It seems to level out when the engine is running. I’ve noticed that the compressor runs occasionally when the car is just sitting in the garage. Do I have an air spring problem or is this normal? The bag seems to be OK so could it be a leak somewhere in the plumbing to the right side? I’d appreciate any suggestions.

Bert

There has to be a leak in that circuit that gets overridden when the car is running. If it's the valve leaking internally, you'll have a hard time checking without removing things. If there's an external leak, try spraying the lines and spring with soapy water to see if you can pinpoint the leak. If it takes a long time, it'll be hard to find and would be a vary small bubble.

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Bert

MarksMarq

Thanks Bert. I did some actual measuring and the car is about 1" lower on the right rear that the left rear whether the engine is running or not. When I turn off the engine and get out of the car, both sides drop about 1/2 inch. Does this mean something different than a leak?

Bert

The height is almost always different from side to side. Can you see the difference when looking at it from behind? The best way to get an accurate reaging is from the bottom edge of the wheel (rim) to the fender well. Not to the ground. I don't remember the specs from side to side, but I think that's within limits. I'll see if I can get more info.

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Bert

MarksMarq

The difference is apparent to me and a couple of others have commented on it. This car is like new inside and out and it's worth it to me to fix some of the minor problems it has. It has pretty much been sitting in the garage for the last 14 years until I bought it in January.

After sitting overnight the measurement from the bottom of the rim to the top of the fender well on the right side is exactly 23" and on the left side is exactly 24".

I appreciate you help--

Bert

A noticable difference isn't right. Have you looked under the car to see if the air bags look the same. Sometimes they get folded wrong and they have to be removed and refolded. There could also be something bent underneath.

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Bert

MarksMarq

Both bags look fine. Do you know if the compressor fills both bags together with equal pressure or separately? Could the right bag just need more pressure? Do the solenoids control the pressure in each bag? Could it be a bad solenoid?

MarksMarq

Does anyone have experience replacing air springs? Will it inflate normally after installation? The Chilton manual says to use a special tester and I wonder if I really have to do that? If so, I guess I take it to the dealer.

Bert

I think it would be a good idea to take it to the dealer for replacement. Here's the instructions from the manual The refill procedure uses a special Star tester to finish the job. That's about all I can help with since I only worked on te Police versions and have no experience with the air suspension.
Removal
SPECIAL SERVICE TOOL(S) REQUIRED
Air Spring Removal Tool T90P-5310-A

1.Turn air suspension switch OFF.
2. Raise vehicle on a hoist as outlined. Suspension must be fully down with no load. All 4 wheels
3. Remove heat shield as required.
4. Remove spring retainer clip.

WARNING:
DO NOT REMOVE AN AIR SPRING UNDER ANY CIRCUMSTANCES WHEN THERE IS PRESSURE IN THE AIR SPRING. DO NOT REMOVE ANY COMPONENTS SUPPORTING AN AIR SPRING WITHOUT EITHER EXHAUSTING THE AIR OR PROVIDING SUPPORT FOR THE AIR SPRING.

5. Remove air spring solenoid valve.
6. Remove spring piston-to-axle spring seat.
Insert Air Spring Removal Tool T90P-5310-A between axle tube and spring seat on forward side of axle. Position tool so that its flat end rests on air spring piston knob. Push downward, forcing piston and retainer clip off of axle spring seat.
7. Remove rear spring.

Installation
1. Install air spring solenoid valve as outlined.
2. Install air spring into frame spring seat, taking care to keep solenoid valve air and electrical connections clean and free of damage.
3. Connect push on ring spring retainer clip to knob of spring cap from top side of frame spring seat.
4. Connect air line and electrical connector to solenoid valve assembly.
5. Install heat shield to frame rear spring seat, if required.
6. Align air rear spring piston to axle seats. Squeeze to increase pressure and push downward on piston, snapping piston to axle seat at rebound and supported by shock absorber.

CAUTION:
Air rear springs may be damaged if suspension is allowed to compress before spring is inflated.
7. Refill air rear springs.

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Bert

MarksMarq

Bert--

Thanks for the feedback. What's your suggestion? Should I fix the air springs or just replace them with coil springs? This is a 16 year old car.