Air Suspension Help

[quicker]

Guys,

I wanted to post this scenario/history to see if any of you could give me some direction on where to start troubleshooting this.

Background: 2009 Expy Max with rear air suspension and auto leveling (coils in front). PO had replaced some compenents under warranty a while back. I have had the truck for 3yrs and no issues with air suspension. 200k miles.

So.... here goes:

I have towed a travel trailer with the truck and had no issues. I tend to turn the air suspension off when towing because it seems like the auto leveling feature kept pushing the truck too high when loaded.

A couple of weeks ago I hooked onto a trailer (rugged dump trailer) and noticed that the truck squatted severely. I didnt tow the trailer far, just a couple of runs across town. I believe I had turned the air suspension off as I normally would when towing but when I noticed the squat I turned it on to see if it would bring the truck up some. The compressor came on as expected but it didn't raise the truck and then I got a "Check Air Suspension" warning on the message center on dash.

Life got busy and I didnt end up getting it checked as once I unhooked the trailer the truck came back up to level.

Then last week I hooked onto the camper and again noticed excessive squat. But the torsion/weight bars dealt with most of the squat so I headed out on the trip.

After returning the truck again came up to level (unloaded).

Then I loaded the truck up with kids and gear (no trailer) and noticed excessive squat.

After this short trip when I unloaded the truck did not come back to level. see first attached pic.


then this morning I start the truck and its was at this same squated level and the pump started. Then the check air suspension warning comes back on and the truck looks like its all the way down on the bump stops. Now when I start the truck I dont hear the pump start. see 2nd attached pic.





So... where do I start troubleshooting? Seems that both sides are deflated equally so it doesnt seem live a leak on just one side?

Any advice appreciated. I am considering switching to coil rear suspension but now I'm almost un drive-able and if there is a quick fix to this I am more inclined to do that first and then spend the money on coils later.

I'm still on the fence on coils also as I really cant complain about the air (until now ha!) as it has worked well and been very useful with a truckload of kids and gear.


Thanks in advance.

 

[bobmbx]

Looks like a trip to the dealer is in your future. You have an air leak, or the compressor isn't working. Or both. Or your sensor is bad. I don't think the towing you described has anything to do with it.

I had a Lincoln Continental that had bad sensors on the front, and often at the most inopportune times, the front would suddenly puff itself all the way up to the stops, then drop to the bottom. That was both unnerving and dangerous. Granted, it was a total air suspension system, no shocks or springs on the back. Just rubber "donuts".

 

[quicker]

So just an update, the compressor is still coming on when I start the truck and runs for a while and then stops. I removed the headlight and can't see/hear any leaks around the compressor but the compressor does get ridiculously hot before it stops but I assumes that because it is running a little longer than normal.

 

[ExpeditionAndy]

Here is my experience with the previous generation. I had an 05 with full air suspension. I noticed that the compressor seemed to run more and more but other than that everything seemed okay. One day I noticed that I felt like I had no suspension and like I was driving around on two basketballs. I figured I had a leak. The dealer did the diagnostic, sensors were good, connections were good, bags were good, compressor was bad. I had the compressor replaced and it was like brand new. The compressor would come on every so often run for less than 30 seconds and shut off. If I pulled on to a slight incline at a traffic light the compressor would run to raise the rear to level the truck.

Personally I liked the system. The ride was good and If they had offered it on the 17 I would have ordered one with the air suspension. If it was my truck and I planned on keeping it longer I'd fix it rather than change it. If you are only going to keep it a couple of more months do what you need to do so you can drive it.

Best to bite the bullet and take it in and have the dealer diagnose if for you and then you can decide what to do.

Just my nickle's worth of advice.

 

[docraymund]

Don't risk damaging your compressor by overheating it. Turn it on, wait till the truck is lifted, then turn it off. If it squats after a few days, you have a leak. You can spray soapy water on all parts to locate it.

 

[quicker]

thanks guys. at this point it wont lift the truck off the bump stops at all. I'll stop into the dealer and see if they can diagnose the problem and go from there.

 

[1997SCEBFEX]

as described above, pretty sure you have a bad compressor &/or leak. my trailering experience and literature noted to turn off air suspension system, connect trailer etc., then re-energize. did this for several cross- country trips with no problem.

on the old systems like my '97, we have an "air union coupler" that feeds the rear bags only and prone to fail. a twenty something dollar part under the master cylinder. I have replaced that once in ownership, then the compressor 4 years later.

hot-absolutely. the air system pressure is several hundred pounds and just like a garage/home compressor, they heat up doing what they do.

hope you get it figured out.

 

[kenf]

HI, Went through this with my 07 expy. First i disconnected the battery let it sit for 30 minutes and re-connected. Did this to reset everything in the truck. I did have a slight leak as the suspension was low in the morning. They usually leak at the dryer input. Its a small orange o-ring . You can twist of the dryer ( 1/4 turn) and replace or turn it over and re-insert the dryer. The dryers are cheap and I changed mine as there was a lot of moisture in it. The rear air lines are easy to disconnect just pressing the metal ring and they pop out. Well this worked for 2 more years then another compressor failure as I had a rear sensor go and the compressor pumped till it died. So swapped out for coil over shock, nice ride but not as firm for towing as its like a normal passenger car and with the weight of the truck its ok with bumps but can get a little bouncy over wavy surfaces. Good thing is I do not have to worry again about it. I do like it. Anyways live in Quebec Canada and our salt and bad winter weather is bad for this type of weather especially the suspension levellers in the rear.
Good luck

 

[limitedex]

Hey OP, sorry for the bad luck.

If you're interested I have lightly used coilovers that replace your air bags I could sell. I went back to my air suspension once I learned you CAN lift the rear with stock air suspension. So I basically have no use for the aftermarket coilovers.

Here's where I got em. (Mine is NOT EL)
http://www.strutmasters.com/product...on-el-rear-suspension-conversion-kit-fu3rb-2/



Email if interested.
[email protected]

 

[quicker]

ok heres the update. The saga (or the stubbornness) continues. I took the truck to dealer today to get them to diagnose. I explained the situation and that I didn't want them to spend a lot of time chasing this if it didn't look like an obvious fix.

They checked for codes and checked for leaks (visual not smoke test) on the hoist. Nothing obvious. I spoke with the tech and he said he was fairly certain it was the compressor. I didn't feel like paying them to do anymore diagnosis at that point.

Question: has anyone ever used the aftermarket compressors? Rockauto has them pretty cheap but not sure about the quality. But a fraction of the cost of the dealer supplied compressor.


So tonight when I got home I decided to pull the compressor out. I remember reading somewhere that if you remove the output line from the dryer you can't use the same fitting to put it back in so I left the output line on and removed the dryer from the compressor. Ran the compressor and it was putting out air (without the dryer connected) but it was hard to tell how much. Removed the cylinder and everything was intact (no broken connecting rod or anything). The rubber seal on the piston looks old and dry so that could perhaps be the problem in that its not pushing enough air.

While I had it apart I used my shop compressor to drive air into the input of the dryer to see if I could get any activity on the back end air springs. Regulator was set at approx 100-110psi but when I tried to force air into the dryer nothing happened it just built up when using blow gun with rubber tip and came out violently when I removed the blow gun. So pressure seemed to be building but just wasn't going anywhere.

I tried this with truck off, with key on and with truck running as I remember reading somewhere that the key needed to be on for the solenoid to allow air into the air spring.

Question: Any idea why the air wouldn't go into the air springs through the dryer when I was manually applying the air? Is it possible that the air dryer is completely plugged? Did I need to do something different to get the air to go into the air springs when applying air manually?

Thanks in advance guys.