FAQ: Automatic Leveling Control (ALC) Concerns

My guess is there may have been a leak somewhere in your system at one time. Rather than replace all the lines, the pump, connections, etc., they took a shortcut and coupled the shocks, essentially creating an air bridge to hold pressure. Clever solution, actually. You could set the ride height by raising the rear end before installing the air line. In theory it would hold for quite a long time.

You know the system works, so maybe try reconnecting the lines from pump to shocks, then hunt for leaks. Might be a simple fix.

Yes, I'm positive it's been modified. I will try to snap some pictures soon. I agree it's not really needed during daily driving without having a large load in the back, which I rarely will.

That sounds exactly right AA, it does in fact seem to be acting like an air bridge. As long as I don't have a load in the back, it's fine as is for now.

I'm considering just installing the AK29 kit and removing the pump/level sensor and try to sell them. But I'll see I can make that kit work the compressor in a way.

im Having A Simuliar Problem I Hear My Compressor Running I Just Dont See My Car Rising I Looked At My Shock & I Think There Old & Leaking So Can I Buy Replacement Air Shocks i keep Hear y`all Talk About ak29 Kit What Is That ?

There is definitely a leak. If you act quickly, you can disconnect the air pump before it burns itself out. There's probably a fuse, or relay under rear seat. A good direct replacement for our shocks are the Monroe max-air - read earlier posts in this thread for model # and other options.

The ak29 kit is a low cost bypass valve that lets you fill your shocks with an air pump. The automatic leveling feature doesn't function, but you can control the level of the rear end by adding or releasing air, like adlusting pressure in a tire. Most people do this because their pumps failed. It's also convenient if you want to experiment with different ride heights for handling purposes.

Aaron,
Can the AK29 kit also be used to repair all or part of the original air lines?

From my showroom thread, how does the level of the rear look? This is how it usually sits. Seems normal to me, or slightly high.

Quote :

Aaron,
Can the AK29 kit also be used to repair all or part of the original air lines?

It might work. Depends on where the leak is at. If a line is cracked, you could use the lines in the ak29 kit to patch - line diameter is the same. Or you might try some hard vacuum line from the local parts store. It seems like a very similar product, comes in different diameters.

LARRY70GS wrote:

Aaron,
Can the AK29 kit also be used to repair all or part of the original air lines?

l used that kit to do a repair while on the road a couple weeks ago. Needed only the fitting end and a foot of tubing, replacing the short section by the shock. I used a plastic compression union fitting to "splice" the tubing together. Aaron used one of the same unions a couple years ago, from me. It's an ok temp fix, imho. I still want to replace both my lines completely, back to the compressor. Haven't looked yet at what is needed on the compressor end of the tubing. I also do not know if the lines in the kit are long enough to do that.

THANX MY COMPRESSOR ONLY RUNS NO MORE THEN 1O-15 SECONDS & ITS BEEN DOING THAT 4 YEARS I THINK IMMA GET THOSE MONROE MAX AIR SHOCK I WANT EVERYTHING TO WORK AS IT SHOULD

Dave, thanks again for sending that coupler - still holding up well after 5 years. It seals great, never leaks any air.

Cool, I thought you were going to use it as a temp fix. I'm surprised it's still holding. I had to install one also, but the line pulled out of one side after a day. I re-tightened it and so far it's ok again after a few days. Wouldn't mind just leaving it in place indefinitely.

BigRay1125 wrote:

THANX MY COMPRESSOR ONLY RUNS NO MORE THEN 1O-15 SECONDS & ITS BEEN DOING THAT 4 YEARS I THINK IMMA GET THOSE MONROE MAX AIR SHOCK I WANT EVERYTHING TO WORK AS IT SHOULD

Actually... if the compressor is running only 10-15 seconds at start-up you probably don't have a major problem. If there is a bad leak the compressor will run ~45 seconds then cut off. So you probably have a slight leak.

According to the FSM, the compressor should run for 3-5 seconds, after a 17-35 second delay, every time you start the car. Mine does so.

Mine runs for 3 seconds also, unless it's sat for a day or more, then it runs maybe 10 after startup.

@ BigRay - what you probably want to do is use a watch to actually time the compressor run, see how long is it really. You probably also want to get under the rear and look at the shocks. If they look oily it is time to replace them. If the rubber bladders show cracks, they should be replaced but you have time to shop around a little.

If you replace them with MA-822 Monroes or the KYBs (I forget the number) they plug right in if you have the factory lines still. Typically a push-on fitting with a wire bail that clips onto a ridge on the air nipple on the shock itself. If your air shocks were replaced before by someone who installed an aftermarket line kit (typically a screw on fitting). You can get Delco shocks from Rock Auto with new mounts already attached (judge by the pictures on the site). For my car there are 2 delco choices shown one with mounts and one without. If you are replacing mounts the Delcos with mounts are more or less the cheapest way to go. If you are reusing old mounts then the KYBs or Monroes. It will most likely cost you more to get the Monroes or KYBs and as well get new mounts separately, but not so much more that I would not do it. In my experience the OE mounts were much larger than the replacements so although I bought replacements I reused the OE mounts this time. In another ~150,000 miles I might have to go ahead and use the new mounts (this is my 3rd shock replacement and the first time I did not use the OE GM shock).

You may have read elsewhere that I recently replaced my air shocks with KYBs. They ride nice but it's a little weird. Its a smoother ride than any with the OE shocks. But the ride is firmer overall - I mean, maybe I was due for fresh dampers but the KYBs are, well, supple.

As for the replacement it's pretty easy. You will probably need new hardware for the nuts/bolts on the bottom though. You'll need 1-1/2 to 2" long grade 8 or better bolts with nuts and washers, or speednuts, use the old ones as a guide. I talked to a local Goodyear mechanic about it, he said they replace the bolts and speednuts with coated (black or chromate) common grade 10 hardware as a matter of course when they do these.

Albertj

You may also want to check the rubber hoses on the compressor it self...
when i got my car one of the lines (looks like a vac line) had rotted away
its worth a look. its usually the shocks that go bad and in turn burns out the
compressor.

Did a quick search and found nothing on the topic. Has anyone turned their auto air suspension into an adjustable one? I was thinking of some kind of variable resistor mounted on the dash that controls a solenoid valve after the air storage tank that could be used to dynamically adjust the psi of the air shocks. It would have to let amounts of air pass and escape and be controlled with a remote interface.

I am not clear on this but I think the OEM shocks are adjusted by a height sensor? I am sure this could be reconfigured from the sensors to a variable dial that controls the psi level in the shocks,,right?

There is an armature mounted on the left rear suspension that activates a switch to turn on the air compressor when the rear end is low. The arm moves as the suspension is compressed from weight, or if there is too little air in the shocks (an air leak will trip the switch continuously). It's an on/off, not a variable motor speed control.

A simple set-up would consist of an "up" switch up front that would raise the rear, and a "down" that would release pressure (solenoid, valve). A pressure gauge could give you a status update in PSI, or if you are good with circuits, you could use an electronic pressure sensor to drive a signal fed to something like the AeroForce Interceptor. The AeroForce has two aux sensor inputs that can be used to calculate values based on user-created formulas. For example, you could convert PSI to ride height, or a percentage from min to max positions.

Keep in mind, the OEM air pump wasn't designed to be operated much more than when fueling up, or when people or luggage are adding weight in back. By controlling it freestyle, you might decrease the life of the unit. A few of us have had units burn out when air leaked from the lines or shocks.

It's a good idea, though. The AeroForce would run you $250 or so, but you would use it for all kinds of monitoring (might cause you to put the Torque app back in your pocket).

I really like AA's idea if you don't want the stock ride height - a manual three pole switch wired directly to the pump would be a cool way to go. Up for up, down for down, middle for no change... you would probably not need to use it much. Remember that the OEM design is to run the pump and exhaust once per startup to exercise both valves regularly.

My car is riding too high (measured the gap from the top of the stock size tires, up to the wheel well molding, and it's a 5" gap) I had the same shocks installed. The front feels bouncy could it be because its too high in the back?

Could I let out some of the air in the lines myself? It's bugging me. Thanks

If the airlines were plugged into the shocks before the car was lowered back on the ground and back suspension compressed, it could keep the air in shocks from escaping and keep the back lifted higher than desired. I was told to let the car down first then plug the airlines in to avoid this. Not saying it's the solution, just a possibility to consider.

Lisa P wrote:

My car is riding too high (measured the gap from the top of the stock size tires, up to the wheel well molding, and it's a 5" gap) I had the same shocks installed. The front feels bouncy could it be because its too high in the back?

Could I let out some of the air in the lines myself? It's bugging me. Thanks

The front will feel bouncy if you have OE struts even if new. They are valved to allow a soft ride and not transmit shock from pavement cracks. Even worn gabriels and kyb's are stiffer.

As for the rear - when the car is parked the rears are supposed to vent down to about ambient atmospheric pressure. There is no pressure sensor, though. The only measure is the angle of the arm that follows the attitude (height) of the rear end.

If you had the car in the air and connected the airlines then there would be a volume of air trapped at ambient temperature and pressure. But not enough to hold the car up after a drive cycle - when the computer opens the vent valve to reset attitude (about a couple minutes after you turn off car and park) it should have settled to proper height. Actually, it should have hit proper height during the initial drive because the solenoid should have opened to vent the system down after several minutes into the drive.

So the only thing I can think of is you have a stuck or failed vent valve or maybe the vent valve is somewhat sticking and you are driving very short trips.

Albertj

...or your suspension is binding somewhere - bad shock, misinstalled spring.

And just throwing this out there, my experience is having the back high results in less front bouncing. I have orig front struts and crappy roads. After retrofitting the rear air shocks so I could manually control their pressure, I run around with 75 PSI in the back, very stiff and high. I find this majorly tames front bounce. (Though once I go coilovers its all a non-issue.)

Karma wrote:

And just throwing this out there, my experience is having the back high results in less front bouncing. I have orig front struts and crappy roads. After retrofitting the rear air shocks so I could manually control their pressure, I run around with 75 PSI in the back, very stiff and high. I find this majorly tames front bounce. (Though once I go coilovers its all a non-issue.)

Hi Karma

Yeah thinking about it, pumping up the rears would tend to pre-load the front struts and reduce bounce if only due to the constant additional down force. Also if you were running Monroe sensatracs it would tend to get the strut position into the stiffer zone.