Suspension Problems

[Cliffyoung]

I have a 1993 Lincoln Mark viii which has problems with its suspension. Everything with the suspension seems to work except it over-inflates the bags which makes the ride very stiff. I took it to the Ford Lincoln dealer in Baxter, MN. They didn't tell me what was wrong with it except that parts are no longer available and they recommended replacing the air suspension with a coil system. I don't think they knew how to work on it or how to diagnose the problem. I have the car at a shop that restores older cars. The technician there said that he put it up on a rack and felt the bags. He said they were extremely hard. It was on the rack for two days before the bags bled off their pressure. He then lowered the car and it rested on the floor in a lowered position. He then started the car and the air suspension started up and raised the car, however the bags again over-inflated. He said it seems that everything seems to work except it over-inflates the bags. I have had the car for 20+ years and I want to restore it and keep the air suspension. Can anybody give any advice as how to determine what is wrong with the suspension. Also, it appears parts are available. Is there any recommendation as to where to look. I apologize for being wordy but I am not very knowledgeable on this issue.
Thank you
Cliffyoung

 

[tixer]

Welcome, Cliff! And greetings, from St. Paul. It's always great to see another Minnesotan on here.

There are others here far more knowledgeable on the suspension system than I, but I got to your post first. So here we are.

The first thing I'd look over are the ride-height sensors. You'll have three. One for each front wheel, and one for the rear. It's about 7" long, and has a plastic "accordion" bit on it. These attach with a "ball and socket" affair at each end. If one has become disconnected, it could certainly explain your problem.

If they look good, check over the associated wiring and connectors. I suppose there's a chance one could fail, although I've never seen it myself.

It's also worth noting that the shock absorber built into the front air-struts can "bind" as it ages, which could also explain the harsh ride. It may be worth trying the 'ol "push on the fender" suspension test on each corner, to see if you can track down the offending part.

Do keep in mind that when fully inflated, they should be pretty hard. They're supporting 3,800 lbs, after all. If your ride-height is correct, I'd guess things are actually working as they should. If it's truly putting too much air in the bags, you'll see the car in "4x4 mode"

Obviously, a "stock" car would be a better example of this, but here's what I have available at this moment..

Exhibit a: "Too Full"



exhibit b: "Juuuust right"

 

[ONLYTONY]

On all my cars, I get 27-28" measured from the ground to the fender well. I don't understand how the bags bled off pressure. If one front sensor popped off, just that wheel will be way up. Back sensor would make the rear of car high. If all wheels go high, I'd be thinking module maybe.

 

[driller]

I have had the car for 20+ years and I want to restore it and keep the air suspension. Can anybody give any advice as how to determine what is wrong with the suspension. Also, it appears parts are available. Is there any recommendation as to where to look.

Welcome Cliff!

I hope the group here can help you out. My thoughts...

First, the air bags are nothing more than an air "spring" and when properly inflated to the correct height would not by themselves give a "harsh" ride. The front shocks which are integral to the front air bags are likely worn out, particularly if they are original which I gather from your post they likely are.

The rear shocks are independent from the air bags. Are they original? Have you noted any 'clunking' sound emanating from the rear suspension? Usually such a symptom is a worn top shock bushing. They are after all, 20 years old.

And therein lies the problem, the age of the suspension components. I have seen far to many people complain about the air suspension and then go the route of coil springs and new shocks and rave about how much better the ride is. The fact is if the air suspension was properly repaired as well as replacing the old shocks, the ride would be much better. Replacing worn out suspension components simply makes the ride better all around.

And furthermore, there are several other suspension components and bushings to wear that would negatively effect the ride quality as well. That's a whole 'nother subject.

I would first determine if the suspension is operating as it is designed to. Check for proper ride height. Then perform a leak down test by driving the car normally then parking and shutting of the suspension switch in the trunk. See if it leaks down overnight, a day, two days or a week.

Lots of help can be found in the Technical section by following the "Lincoln Tech" link at the top of the page.

By the way, new front OEM airbags are obsolete, but I have been hearing encouraging news from others on the Westar brand now available at most parts store chains.

 

[billcu]

I agree check the height to see which wheel has the problem first.

When I bought my green 94, both rears were overinflated due to a vent valve problem. The fronts vented ok but the rears were too slow to vent, then the system timed out.

The stock parked height (from the 94 service manual) measured from the bottom of the wheel rim to the bottom of the fender wheel arch is 24.5" front, 24.25" rear +- .5".

The gen 2 Manual gives you more tolerance.

 

[Lvnmarks]

Hello Cliff, I as well live in Minnesota and I have a specialized tester that I can hook up to your car and test each component and search for error codes.

I would be more then willing to bring it up to you as I'm in the Mille Lacs area frequently and take a look at it for you.

I want as many of these cars on the road as possible, hopefully we can find a solution.

 

[Cliffyoung]

I want to thank the responses which I got concerning the suspension problems with my 1993 Lincoln Mark viii. The responses were most helpful and informative. The problem was with the struts. I replaced them with new ones. I got them from CARiD at a cost of $354.00 each. They were made by Westar. The ride is really nice compared to what I had before. Other things which I had done was have the ball joints replaced and I also found that the Anti-sway bar was broken. That was also fixed. I just got the car back just a few weeks ago. I don't drive it in the winter time so I put in my garage and disconnected the battery. Next spring I will start on fixing or replacing other things on the car, such as the radio, transmission, a voltage leak and then finally I'll have it repainted. Anyway thanks for the help and have a merry Christmas. Cliff

 

[tixer]

That's great news, Cliff! I'm glad your'e back "up" and running. It sounds like the car got some much needed maintenance.

I'll bet you're already thinking about getting it back on the road come spring...

 

[billcu]

Glad you got it fixed Cliff, it's great that you stayed with the air suspension. Let us know how the Westar airsprings work out, as they seem to be the only option lately.

 

[driller]

Good news to hear. I've been hearing mostly good feedback on the Westar brand.

And for those of you who didn't know, CARiD is a sponsor of the forums. :wink2-green