Air Help - in General

Having Ford or Lincoln Air Suspension Problems? Air suspension is such a specialized area, that only 1 in 20 mechanics are good at diagnosing these systems. What does that mean? Most of the time they basically throw parts at the vehicle until they either get lucky and fix it.....or the customer runs out of money! Here at American Air Suspension, we can assist you in diagnosing the air system and supply you with the best affordable replacement airbags, air compressor, dryer and solenoids if you are set on keeping the air suspension. If you're looking for a less expensive, longer lasting solution, we offer Air Suspension Conversion kits for just about any make and model so you can quickly and safely convert your vehicle to a conventional coil spring suspension system.

Vehicle Specific Air Suspension Help:

General Air Suspension FAQ's:

How do I disconnect an airline?


The airlines are held in an air suspension dryer or solenoid by means of a little brass collet on each airline. This collet allows the airline to go in easily, but the 4 little jaws dig in making it difficult for the line to pull out.


The way the factory designed the airlines to be released, is to push the little orange collar(which puts pressure on the collet) in towards the dryer with one hand, while at the same time.....pull the line out of the dryer/solenoid with the other hand.

disconnecting an air suspension line

NOTE: While this was the way it was designed to work, in reality, if the air lines have been in the collet long enough, the 4 little jaws of the collet may have "dug in" and may require a little more effort to remove. If you try the normal route to remove the lines and it gives you a hard time, try pushing the line in with one hand while pushing the orange collar in with the other hand. This will "usually" help release a stuck collet jaw. Keep in mind, if your car is say '93 or so, those collets have been "dugg-in" to those lines for a long time. It may take a few times to get it.

How do you Leak Test?

What should you leak test?

To be successful in diagnosing your air suspension problem, you have to first figure out what to test. While everyone wants to think that the reason their 50K SUV is going down is because of something cheap & simple like a leak at the dryer or solenoid, in reality, this just isn't the REAL problem!

If you look in a Ford shop manual, it says in black & white that the line connections were never designed to be totally leak-free. The reason they don't care if they have a small leak at a line connection, is because of the solenoids. These vehicles have a solenoid on each air spring that acts as a gate for air and are normally closed. These solenoids are a very good, dependable design and very rarely fail. Air is held in the Lincoln Air Bags by a solenoid and it is designed to remain in the airbag until the module signals a solenoid to open. At this time, the air will either go in the airbag or back out.....depending on what the module is trying to accomplish. The module(brain) makes ALL the decisions based on the info that the height sensors have given it.

While these systems are designed from the factory to be able to make any adjustments for an hour or two after shut down, they are also designed to go to sleep or shutdown after this time. During this off-time, the system won't make any adjustments and really doesn't give a hoot what the car is doing.


If the vehicle you're working on goes down after the vehicle has sat a while, turn on the ignition to see if it'll pump back up. If the air suspension compressor IS able to pump the car back up, focus your efforts on the Lincoln Air Bags or the 2 solenoid seals the size of your pinky, that seals the solenoid to the airbag.

Forget about any leaks in the airlines, where the line goes in the solenoid or dryer, as a leak in the lines just makes the system less efficient and will only increase raising the time of your vehicle.

In other words, if it can pump up, apparently any leaks in the lines weren't severe enough to cause any problems. Also, if the system usually pumps up the vehicle in say....20 seconds, it may now take 25-30 seconds because of the leak at the line connection!

If the vehicle you're working on goes down after the vehicle has sat awhile, turn on the ignition to see if it'll pump back up. If it DOES NOT pump back up, first find out if the Lincoln air suspension compressor is running.

If the Lincoln air suspension compressor IS running, a pretty severe leak at a line connection and/or weak compressor maybe at fault.

If the Lincoln air suspension compressor is NOT running, focus your efforts on why it's not coming on, as a bad air suspension compressor relay maybe dropping the ball or the module is seeing a problem in the system and is trying to shut down the system.

Keep in mind that ALL the Lincoln Air Bags have their own solenoid. The solenoid acts as a gate for air and no air should go in or out unless the solenoid is opened up by the module. By turning the suspension switch off, you're disabling the solenoids, thus no air should escape....unless of course there's a leak.


By far, the easiest way to test for a leak on a Lincoln Airbag, is to allow the car to vent down after shutting off the engine and opening and closing the door.

IT IS VERY IMPORTANT TO MAKE SURE THE CAR HAS LOWERED PRIOR TO TURNING THE SUSPENSION SWITCH OFF, OR THE TEST WON'T BE ACCURATE! Your goal is to get the vehicle to sit at the height it sat at most of it's life.

Dry Rotted Lincoln Airbag

If nothing else, wait 5 minutes after you turn the ignition off...then turn the suspension switch off. The car should have vented by then.

After this, turn the suspension switch off and measure the height of the 4 corners of the car with a tape measure and write it down. Now drive the vehicle for a few days. If the vehicle has a leak, the car should go down after driving.

NOTE: Depending on the severity of the leak, it may take more than one day to leak down. This is the case more times than you would think.

By all means, if the car goes down after 10 minutes of driving, turn the switch back and resume your journey. You have answered your question.


It's been my experience as a former Ford/Lincoln factory trained and certified technician, that if the solenoid has never been removed before, most likely the leak isn't from the o-rings that seal the solenoid to the Lincoln Airbag. Now if the solenoid had EVER been removed before, the o-rings should have been replaced at that time. If you have an old o-ring that has never seen the light of day and all of the sudden, after 10 years of being cooped up, it is released from tension, it will expand. If reused, it WILL eventually cause a leak . It might take a day, a month, or even a year, but it WILL leak at some time down the road.

In other words, if you replace your Lincoln Air Bags, make sure you replace the 2 x o-rings that seal the solenoid to the airbag. If you don't, it's not a matter of IF it will leak, but more like WHEN. It would be in your best interest to also replace the little o-ring that seals the air line to the solenoid at the same time. Because this o-ring is AFTER the actual sealing part of the solenoid, if this o-ring leaks, it will only affect the operation of the system while the solenoid is opened, like when the module is making a height adjustment. Not while sitting overnight!


Leak testing the airlines of a Ford or Lincoln is fairly straightforward. By simply spraying a soapy water solution, comprised of a shot of dishwashing soap & water, this will show you where small air leaks are. You just look for the bubbles.

REMEMBER, leaks at the airlines, whether it's the line going in the solenoid or dryer, just makes the system less efficient and will only increase raising the time of your vehicle. In other words, if the vehicle can pump itself up, apparently the leaks in the lines weren't severe enough to cause any problems. Also, if the system usually pumps up the vehicle in say....20 seconds, it may now take 25-30+ seconds because of the leak at a line connection! This is because the compressor has to make up for the air leaking out plus build pressure and raise the car.

Why do I have a leak where the dryer goes into the compressor?

A leak on the compressor flange, where the dryer nipple locks in the head, is usually an indication of an overworked compressor. This is usually due to a leak(s) in the system.

> Melted Oring

If the compressor assembly is not allowed to cool sufficiently in between cycles, the head on the compressor may reach 450+ degrees. This is extremely hard on the sealing o-ring and dryer nipple. The o-ring can be taken to a hardware store and matched up with a standard o-ring if need be, but it is better to use an orange "neoprene" type o-ring that will endure higher heat than normal rubber.

To replace the sealing o-ring, remove the phillipshead screw securing the dryer to the compressor assembly, then turn the dryer clockwise about an eighth of a turn, then pull the dryer out to unlock and remove.

Replace the o-ring and inspect the dryer for damage, then perform a leak test....or you'll be doing this again in a short time.

Even after replacing the collet and orange collar, the line still leaks. Why?

This is a very common misconception. Neither the orange collar nor the brass collet seals the air line. There is a small o-ring approx. half inch deep in the hole the line goes in that actually seals the air line to the dryer or solenoid. The picture below shows the order of each part going into the hole.

#1) O-Ring #2) Nylon Washer #3) Brass Collet #4) Orange Collar

Does it matter which air line goes in each hole of the dryer?

No. The dryer acts as a common manifold for the air suspension and there's no special order for the lines to go into the dryer. However, some lines can "fit" better in a certain hole than it does another, so try to insert the airlines where they're relaxed in their holes as much as possible. By doing this, the single o-ring that seals the line won't be in a bind and will seal better. If an airline has tension on it, like being pulled in one direction, the line can't seal like it was designed too.

Why does the air suspension act up more on colder days?

The thing that probably throws more people off track than anything else, is the effect of the weather on an automotive air suspension system. Keep in mind the rubber air bladders used for these airbags are only 2mm thick. The warmer it is outside, the more pliable the rubber is and better able to "seal" itself. The cooler the weather, the harder the rubber gets and less able it is to seal itself. This difference in temperature doesn't just mean winter time either, it also includes just the sun going down. If you checked the weather every night, you would find most of the time that the system leak down coincided with the cooler nights. Also, depending on the outside temperature and the stage of the leak, it may only leak 1 or 2 nights a week early on. This is also why you may never notice a leak down problem in the early stages of a leak while the car is garage kept. Being partially blocked from cooler weather goes a long way sometimes. One thing is certain though, with age the leak(s) will always get worse. While you may think you can cheat simply by parking the car during the winter as a way around this problem, you'll find out sooner or later that the leak just gets worse will time. In other words, as time goes on and the leak gets worse, you'll start noticing leak down problems even in warmer weather.

Whether the vehicle is a Ford, Lincoln, Mercedes, Lexus or whatever, a change in the weather(cooler) leads to more air suspension system misdiagnosis than anything! It is also the #1 reason why the first thing a novice or untrained tech will want to replace is the module(brain) or the sensor(s). Their thought process is....."if it does something really goofy one day and not the next, it has to be a failure in the electronics". In reality, the problem is NOT in the electronics at all, as it's usually a mechanical leak.
With age, the rubber air bladders used on air suspension equipped vehicles will dry rot and the part of the bladder that dry rots the most is the area of the rubber that is "on the fold" most of the time. When it's warm outside, the rubber is more pliable and better able to seal itself. When temperatures drop however, the rubber gets hard and can't seal itself as easy as it once did. A small leak will ALWAYS turn into a big leak the colder it gets. Keep in mind ANY leak will get a little worse day by day, but you'll never experience as rapid a change than you will with a temperature

Where is the air suspension compressor relay located?

What does it mean when the Front and/or Rear goes down overnight?

In a nutshell, the module(brain) will go to sleep an hour or two after the vehicle is parked. If the a corner or one end of the car goes down after this time, you have a leak. This leak can only be from one of three places, one(#3) of which is very rare.

#1) Leaking Front or Rear air spring.
#2) The air is blowing past the seals that seal the solenoid to the air spring. (if the front air spring was replaced prior, but the solenoids weren't resealed, most likely this is your problem)
#3) Internal bypass, where air bleeds through the solenoid. (Very rare)

After bottoming out, the rearend went down and won't come back up. (Compressor NOT running)

A Lincoln/Ford air suspension height sensor is mounted to the vehicle by way of a ball-stud, top and bottom. This ball-stud allows free movement of the sensor whether the car is up or down. If you're having this problem, the very first thing to look at is the height sensor.....mainly where it snaps on its ball-stud. The way the sensor is designed, it's made to pop off rather than break. With all that being said, if the sensor has popped off, snap it back on and keep an eye on it. "IF" it pops off again, make plans to find one in a junkyard. The little metal tension tab could of been damaged and can be replaced easily from one sensor to another.

Why do you recommend converting on a 03-Up Navigator or Expedition?

Lincoln Navigator air suspension problems

Most weather-related air problems only start showing up later on, approximately 10 years of age. Due to the design of the system, some vehicles will encounter similar problems well before the 10-year mark. Probably the worst one is the 2003-on Lincoln Navigator or Ford Expedition. While the earlier versions (2002 and prior) used a "sealed for life" type airbag(air spring), the Navigators and Expeditions now utilize an airbag that slides over a strut, with the only thing sealing it to the strut is a few o-rings. With this type of design, it is even more susceptible to temperature changes than other vehicle. Not only does it experience leaking problems when the rubber deteriorates, the sealing o-rings will have a hard time keeping the air in when the metal strut contracts due to colder weather. This is the reason why IT IS CRITICAL to use New Ford OEM airbags if you're determined to stay with the air suspension. Even then, if the New Ford part is a few thousands too big, you'll still encounter the same problems when it gets cold. This is the reason why we recommend converting your Navigator to a coil springs. It's the only way you'll be able to count on that vehicle!

How do I Re-Seal My Solenoids?

First of all, TURN OFF THE SUSPENSION SWITCH in the trunk and put the car on jack stands.

NOTE: Put the jack stands under the frame, not under the lower control arm!

Disconnect the 2-pin electrical connector and then disconnect the air line by pushing the orange collar towards the solenoid, then pull the line out. (if the line has never been removed before, the brass collet may be dug-in to the line and may require some patience on your part)

To remove the solenoids, just remove the safety clip that keeps the solenoid from accidentally twisting. You can do this with a flat head screw driver.

Twist the solenoids till they stop. The solenoid has a 2 step removal process. ALL THE AIR IN THE AIRBAG WILL MOST LIKELY RUSH OUT VERY QUICKLY AFTER THE FIRST STAGE IS DONE! If they've never been off before, you may have to help it with a screwdriver or something. The solenoid SHOULD stop at the first stop. I have seen it where it popped off and hit someone in the head, so be careful. At least turn your head when you twist the solenoid.

After the air has stopped rushing out, twist it again and pull it out. Pull off the old bigger o-rings and replace them with the new ones THAT HAVE BEEN LUBRICATED WITH PREFERABLY DIELECTRIC GREASE. Install 2 new o-rings while keeping the nylon washer in between(see pic below)the o-rings.(That's right, the same stuff Ford uses on spark plug wires) The dielectric grease doesn't seem to attack the rubber like vaseline. If you don't lubricate them with something, they will twist and probably won't seal as good as the old ones, which means you did all this for nothing.

To replace the o-ring that seals the airline, first remove the orange collar. Then carefully remove the brass collet(it's easily crushed) and remove the little nylon washer, then the old o-ring. See picture below

How to re-seal a solenoid

Install the new smaller o-ring in the hole of the solenoid, making sure it's flat and seated then the little nylon washer. Make sure both are flat and seated. Install brass collet and then the orange collar.

After these o-rings are replaced, install solenoids, plug in air line and 2 pin connector and remove from jack stands.

NOTE: Install the air lines into the dryer DRY!

We DO NOT recommend using ANY type of lubricant when installing the air lines into the dryer for 2 reasons:

#1) The lines are held in by way of a collet. The small jaws of the collet hold the airline into place. If you put a lubricant on the line, the line could pop out and would result in a major leak, which would allow the front and/or rear of the vehicle to lower all the way down to the bump-stops and most likely do serious damage to the compressor.

#2) The heavy duty o-rings we use on our dryers are made to last 3 times longer than a stock factory o-ring but are NOT designed to be in contact with ANY foreign substance! In other words, using a lubricant on the lines on installation will almost certainly cause reduce the life of the sealing o-rings, thus causing a leak.

In the rear, one side is higher than the other?

FIRST THINGS FIRST. While it may seem the problem is just in the rear, it is possible one corner in the front being high is pushing down on the opposite corner(s). Picture in your mind a rectangular piece of plywood, with a pivot point in the very center. If you were to "pull up" on say the RF corner, it would push the LR corner down. Same thing if you pushed the RF down. It can make the LR corner go up. With this in mind, we recommend measuring all 4 corners and write down your readings. While you may find the difference between the left & right on the back being 3/4 of an inch, the reason could be because the front is off a full inch. In other words, focus your time on the WORST END! The closer you bring the worst end under 1/2 difference side to side, the better off the rear end will be.

While most Fords & Lincolns have a sensor on both sides of the front, they usually only have 1 sensor in the rear. The system tries to keep the rear end up as an average. When one air spring/strut is leaking worse than the other, the vehicle may lean one way or the other.

While most likely the problem is a leaking airbag on the lower side(see note below), it is possible the lower side is leaking some of the pressure from either where the line seals the solenoid -OR- where the solenoid seals the Lincoln Airbag.

It is EXTREMELY common for an airbag to be installed without taking the time to reseal the solenoids. If the solenoids aren't re-sealed, it's not a matter of if it will leak....its more like WHEN! Also, if the 1 small o-ring that seals the airline to the solenoid is not replaced, one airbag can receive more air than the other......even though they are plumbed and wired together.

We've even seen a few that had a leaking "blow-off valve" in the rear( Navigator & Expedition only). Because this valve is on the RH side, if there's a problem with the valve, it'll usually affect the RH side air spring.(because the leak is closer to the RH airbag)

NOTE: As a general rule with air suspension, we recommend replacing the Lincoln Air Bags in pairs. They are the exact same age. If one is leaking now, the other will shortly.

I replaced my airbags and it's still leaking down. What now?

This IS the #1 complaint we have when someone replaces their airbags on a Ford or Lincoln! No matter if the Lincoln Air Bags were installed by a shade-tree or professional mechanic, this still holds true. Trust me, we hear it all the time......"but my mechanic is soooo good, they've been working on my cars for blah-blah-blah. Anytime a solenoid has been attached to an airbag for a length of time, THEY MUST be re-sealed if they're removed. This is the golden rule especially if the Lincoln Air Bags are being replaced!! Failure to re-seal the solenoids WILL result in a leak, sometimes worse than the original leaking airbag problem!

My air suspension compressor is noisey, does that mean it needs to be replaced?

Not necessarily. If the compressor noise has recently gotten louder, yeah, it's most likely on its way out and should be replaced. If the compressor has been making the same noise level for years, most likely it's fine and may last for many more years just like it is. Noises can come from tolerances inside the compressor and may be from a small part being as little as .001 out of tolerance.

How do I repair an air line?

Important thing to remember, the air line is NOT the 1/4 black part. The actual air line is the 3/16 "white" air line in the middle! If you have an abrasion, melted area or broken piece of air line, the best thing to do, is to simply repair the air line. Most mechanics that haven't worked on these systems a lot, instantly want to replace ALL the air lines in the vehicle. While this is one way to do it, it's for sure not the most efficient cost effective way. To replace the air lines, you'll need to source the parts one of three ways:

New from the dealer. The new part may not be very expensive, but replacement cost will be very labor intensive. (get ready for an expen$ive overall bill) NOTE: Make sure to check on the availability of new replacement parts beforehand, as most are discontinued from Ford within 5-10 years.

Used out of a Salvage Yard. Unless you find a yard with a donor car that's been stripped to the bone already where not much is in the way, the yard man will have to remove all the air lines from the donor car. The cost of this will be included in the cost of the used air lines. NOTE: Most yard guys really don't care about the integrity of the part, so they'll probably wind up pulling and yanking(breaking) the air lines! What you'll probably end up with, is at least one break in the air lines that you won't be aware of until it is installed in your car! In other words, you've paid the cost for replacement parts, the labor to remove, the labor to install......now you're no better than when you started out.

Repair the air line. Depending on how much of the air line is damaged, sometimes you can repair the air line without adding any line. This, would of course count on how much slack line you have available. (if the bad part of the line is close to a curved part)
3a) To repair the vehicles air line without adding line, simply cut out the bad part of the air line, cut back approximately an inch of the black protective sleeve on both ends of the line. You should have at least half of an inch of exposed air line on both lines now. Use a single union to join the 2 lines together.
3b) To repair the vehicles air line by adding line, you'll need two unions. Cut out the bad part of the air line, cut back approximately an inch of the black protective sleeve on both ends of the line. You should have at least half of an inch of exposed air line on both lines now. Using the two unions, splice in the additional piece of line. Make sure to put something over the repaired area, as the bulk air line won't have any protection.

Why does my car leak down after an unrelated repair?

So you go to get the oil changed and/or tire rotation on your air suspension equipped vehicle. Later on that day or maybe the next day, you notice the rear-end of your ride is down. You're outraged! ....."What did that mechanic do?.....I'll bet he didn't turn the air suspension switch off!" If that was your reaction, most likely you're wrong. Truth be known, your old dry-rotted airbags(technical term is air springs) were stretched out and instead of leaking badly a month or two from now, it's leaking worse now.

Who's fault is it?

The fact is, the airbags were old and needed to be replaced anyway. Putting the vehicle up on a lift where the suspension is extended all the way, simply stretched out the dry rotted rubber. In a nutshell, the mechanic didn't cause the leak, he just accelerated a leak that was already there.....just by doing his job.