2004 Town Car very stiff rear suspension

felitopaz

Junior Member
8
0
1
Corona, CA
I replaced the airbags and installed new KYB gas shocks about a year ago. Recently I noticed that the rear suspension is very stiff specially when i go over a speed bump. The rear of the car feels like it's jumping off the ground. I removed and checked the shocks and they are in excellent shape. I am leaning towards the airbags being "OVER INFLATED" Any advice would be appreciated.

THANKS
 

Town

Senior Member
4,394
118
63
Ottawa Ontario Canada
This Tech forum is for posting solutions to issues. You will get more helpful info in the Town Car forum here: Lincoln Town Car Forum (1981-2011)

The air pressure in the air springs gives the body ride height. More air pressure causes the rear suspension to raise the body. The ride height is controlled by the suspension module based upon a signal (below trim height; trim height; above trim height) from the height sensor on the rear axle. It is possible that the height sensor has failed but then if the air springs are over inflated the body would look noticeably higher at rear.

Does your car look noticeably high at the rear? What year is your car?

We have a tech article here: Town Car air suspension height sensor replacement and adjustment which gives the correct ride height for a Town Car measured from the top of the rear axle to the underside of the frame rail over the axle.

What tire pressures are you using? Normal are 32 psi front and 35 psi rear. Could the tires be inflated to the max pressure on the sidewall which may be 44 psi or 51 psi. That would account for a very rough ride.
 

Town

Senior Member
4,394
118
63
Ottawa Ontario Canada
Air springs are not created equal. The rubber membrane is supposedly more supple on the Motorcraft parts. But I don't understand why the air springs became hard after a year of acceptable operation.

Steel coil springs are not created equal either. The air suspension light will be on all the time since the 2003 and up are wired differently to older models where you can cut a wire so the suspension light does not come on.

Good luck with your decision. I would suggest you post a thread in the Town Car forum to get more input from those who have installed steel coil springs. To my eye the rear appears higher than normal which is confirmed by the Ford spec showing the rear rides higher with coil springs than air springs.
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felitopaz

Junior Member
8
0
1
Corona, CA
I check the air pressure on tires and the rears were about 35/36 PSI. I lowered the pressure to 32 PSI and the stiffness went away. You were right. Thank you so much.
 

VicOwner2018

Member
46
5
8
It's amazing what a few lbs. difference in air pressure can do.

I have a bone stock '02 Crown Vic with the factory-spec Michelin tires.

Two lbs. air pressure too high and it's a very bumpy ride. Lower it the factory-recommended setting and it rides like a magic carpet.
 
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