How to Troubleshoot the Air Suspension on a Ford/Mercury Grand Marquis

by Allen Moore
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The air ride suspension on a Mercury Grand Marquis gives the vehicle a remarkably smooth ride. Standard shocks are enhanced with air bags, similar to the style used in large tractor trailers. The system is controlled by a computer, which turns an air compressor on and off to maximize rider comfort. However, as age and wear set in, every component in an air ride system is susceptible to failure. When this happens, you might just wish you never owned the car, as air ride repairs can be some of the most expensive repairs you can make to your Mercury.

Step 1

Use the flashlight to examine the air shocks in the front and rear. The shocks are equipped with a ride height indicator. In very rare cases, this indicator can be damaged, giving the air ride system a false sense of the proper ride height. If any of your indicators are bent, missing or otherwise misaligned, have that corrected before continuing your troubleshooting efforts.

Step 2

Start the car and listen for the air ride compressor to kick on. If the compressor does not turn on, check the fuse and replace it if necessary. If the fuse is not blown, you will need to replace your compressor. If the compressor seems to run fine, but cycles often, you need to inspect the system for a leak.

Step 3

Lift the hood and locate the air compressor. With the engine running, spray the soapy water on the connections where the air ride lines go into the compressor. If you see any excess bubbling, you have a leak. If you do not find a leak at the connections, follow each line to its end, spraying each line as you go, continuing to look for bubbles that will indicate a leak.

Step 4

Spray the air bags and air struts at each corner of the vehicle while continuing to look for a leak. Once you find your leak, replace that component. When replacing air bags or struts, it is always best to replace them in pairs. So, if the right front strut is bad, replace both front struts. If the left rear air bag is leaking, replace both rear air bags.

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