Town Car air suspension height sensor replacement and adjustment

Town

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Ottawa Ontario Canada
The 2003 and up Town Car models use a single height sensor mounted to the left lateral watts linkage (in front of the rear axle on driver's side) and the frame above the rear axle. Ford calls it a rotary height sensor to differentiate it from the earlier Town Car models that used a straight telescopic sensor. Once the sensor is adjusted for the car then there is usually no need to adjust it again. So it is expected that these procedures will be needed in conjunction with replacing the height sensor.

Attached is the procedure to replace the height sensor on a 2006 model that should be the same from 2003 through 2011 models.

The suspension ride height is measured between the top of the axle under the frame to the underside of the frame. The distance is approximately 4.75" although 4.5" to 5" is within tolerance. This height will be about 29.25" from the underside of the rear fender to the ground with the car unloaded on a flat surface. The actual specifications are given in the attached document.

To adjust the suspension height you just adjust the position of the height sensor according to the attached adjustment procedure. Since you are unlikely to have the special tool to measure the distance from axle to frame underside and the sensor voltage you will be limited to using a tape measure for the distance and making adjustments on the sensor mounting bolts and checking the resulting ride height once the suspension has adjusted itself to that sensor height setting. It may take several ties to get it right.

Be very careful with each step to switch off the air suspension before working on the car and switch it back on once clear of the car to check your result.

Good luck.
 

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Town

Senior Member
4,398
126
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Ottawa Ontario Canada
1998 to 2002 Town Car air suspension height sensor adjustment

The 1998 and up to 2002 Town Cars use a straight height sensor. If it is being replaced then it needs to be adjusted to the marked position of the old sensor or adjusted according to the attached procedures. Sometimes the height sensor can get folded over and prevent the suspension from raising to trim height.

Replace the ride height sensor according to the attached replacement procedure. Adjust the position of the ride height sensor according to the attached ride height adjustment document. The rear suspension ride height is given in the attached specs document. It is 5" plus or minus 0.3". That is the measurement from the top of the axle tube to the underside of the rail tube immediately over the axle. Since electronic tools to plug into the air suspension module are not expected to be available the adjustment of ride height will be by trial and error. There is an allowance of a half inch in the height of the rear fender lip (at the axle center line) to the ground comparing left to right sides.

Good luck.
 

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24000rpm

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Town, when you are adjusting the height, you are talking about the height on both sides , correct?
there's no way you can adjust just one side and leave the other side alone, I suppose?

The 2003 and up Town Car models use a single height sensor mounted to the left lateral watts linkage (in front of the rear axle on driver's side) and the frame above the rear axle. Ford calls it a rotary height sensor to differentiate it from the earlier Town Car models that used a straight telescopic sensor. Once the sensor is adjusted for the car then there is usually no need to adjust it again. So it is expected that these procedures will be needed in conjunction with replacing the height sensor.

Attached is the procedure to replace the height sensor on a 2006 model that should be the same from 2003 through 2011 models.

The suspension ride height is measured between the top of the axle under the frame to the underside of the frame. The distance is approximately 4.75" although 4.5" to 5" is within tolerance. This height will be about 29.25" from the underside of the rear fender to the ground with the car unloaded on a flat surface. The actual specifications are given in the attached document.

To adjust the suspension height you just adjust the position of the height sensor according to the attached adjustment procedure. Since you are unlikely to have the special tool to measure the distance from axle to frame underside and the sensor voltage you will be limited to using a tape measure for the distance and making adjustments on the sensor mounting bolts and checking the resulting ride height once the suspension has adjusted itself to that sensor height setting. It may take several ties to get it right.

Be very careful with each step to switch off the air suspension before working on the car and switch it back on once clear of the car to check your result.

Good luck.
 

Town

Senior Member
4,398
126
63
Ottawa Ontario Canada
Town, when you are adjusting the height, you are talking about the height on both sides , correct?
there's no way you can adjust just one side and leave the other side alone, I suppose?
Yes the height sensor is for both sides so the height sensor covers both air springs. Your difference in height on rear suspension is likely due to:
1. uneven surface when measuring;
2. a front suspension coil spring fracture or similar;
3. a stuck air spring solenoid valve (with suspension switch on raise the rear of the car until the venting stops then lower the car, a stuck solenoid valve will keep air in that spring so height difference will be reversed);
4. blocked balance hose between the two rear air springs (same test as 3, but may not be completely blocked so do the test quickly and don't wait for complete venting);
5. weaker rubber in one spring compared to the other (measure diameter of each spring while loaded).



Measure from the ground to the underside of the wheelarch on the wheel centerline for all 4 wheels. Ensure the bodywork is in good condition for those measurements. Compare side to side measurements for the imbalance, where a half inch difference is considered normal.

Good luck.
 

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