Rear AIR Suspension Concern

[tvlunn]

Looking for someone who might be able to help with a rear air suspension issue:

1- Purchased 1998 Expedition new - has 120K actual miles
2- Exceptionally maintained and garage kept
3- Never wrecked or in an accident

About two weeks back, the rear end was drooping because both air bags had "leaked" down.

Started truck and rear of truck immediately came back up to its proper position (so pump is functioning)

Let truck sit for two days and all was still well!!!

Then drove truck to town and back - the morning after, all appeared well. However that afternoon the rear end was drooping once again. Started the truck and the rear end of truck came back up to its proper position.

Then everything went well for almost a week and then the rear air suspension lost air once again. Starting the truck resolved the problem once again.

Obviously, something is failing. Has anyone else experienced this same issue?

I may have to wait until things get worse, but what is the most likely culprit?

Thanks so very much!

 

[Ron1978]

Looking for someone who might be able to help with a rear air suspension issue:

1- Purchased 1998 Expedition new - has 120K actual miles
2- Exceptionally maintained and garage kept
3- Never wrecked or in an accident

About two weeks back, the rear end was drooping because both air bags had "leaked" down.

Started truck and rear of truck immediately came back up to its proper position (so pump is functioning)

Let truck sit for two days and all was still well!!!

Then drove truck to town and back - the morning after, all appeared well. However that afternoon the rear end was drooping once again. Started the truck and the rear end of truck came back up to its proper position.

Then everything went well for almost a week and then the rear air suspension lost air once again. Starting the truck resolved the problem once again.

Obviously, something is failing. Has anyone else experienced this same issue?

I may have to wait until things get worse, but what is the most likely culprit?

Thanks so very much!

There are solenoids that operate for each end and side, it help keep the load level, sounds like yours is sticking alittle, I had about same issue at first, I finally spent way to much money and just sold it, " I should have just done coil over conversion and been done"

 

[tvlunn]

Thanks Ron!

If I'm not mistaken, there is a solenoid located on top of each air bag?? You're thinking one of these might be the issue by not sealing properly at times??

I'm aware of these solenoids and that does make sense that one may be failing, sticking or not sealing properly. If I had a leak, such as a minute puncture in an air bag or air line, that would leak at all times ……. not just sometime! But, a solenoid could surely show its face as an intermittent issue!

Anyway, I was hoping someone who had the exact same type issue in the past would respond. I just don't want to start simply replacing parts as that could get expensive. It's difficult to troubleshoot something when the issue is intermittent. Surely, I'm not the first one to encounter this particular type issue.

Thanks again!!!!!!!!!!!!!!!!!

 

[Machete]

Yup. When one thing goes on these air rides it’s the beginning of the end for the entire system. This is why many of us convert to coil over.

 

[tvlunn]

Just looking at the air bags, I can tell 21 years of wear is beginning to show. However, they still look to be in pretty good condition and there is no obvious sign of excessive wear OR a small leak for that matter .................... but it's probably time to change them out anyway.

My thinking is one of the bags must have an extremely small crack or tear and that is where it sometimes leaks air …......… that or possibly one of the o rings on the solenoid valves is allowing air to escape at times.

1) So, do I get aftermarket bags OR is it best to get OEM parts?

2) If most aftermarket parts are just as good, any specific brand better than the other?

 

[Ron1978]

Just a idea

 

[Ron1978]

This is what I would try, it's going to save you money

 

[Ron1978]

This is what I would try, it's going to save you money

View attachment 29676[/QUOTE

You can search for a 2wd setup as well

 

[01ExpeditionXLT]

I have an 01 XLT 2WD (+180k) with self leveling (rear only) and redid my air ride last summer. It was incredibly easy to replace the air springs, solenoids and compressor. My system had been trouble-free for 17 yrs and all of the components were original pieces from 01.

I went with Arnott A2148 air springs, Westar SO-7591 solenoids and replaced the OEM compressor with an Arnott P-2213 that was being clearanced (couldn't walk away from that deal!). I found a new ride height sensor (F75F-3CO34-AC) and replaced mine even though it wasn't giving me any issues (I'll keep it as a spare). I did have to take it to the dealer to have them "recalibrate" the system when it would generate random "CHK SUSPENSION" light on the dash, but they couldn't find any errors when they hooked it up to the scanner and it has been trouble free ever since.

You mentioned that both sides are deflating equally - that leads me to believe that you have a leak in each bag/solenoid which wouldn't be unreasonable after 21 yrs.

 

[tvlunn]

OK - I replaced BOTH air bags with OEM replacements. The replacement process was extremely easy! After 21 years the old air bags were obviously worn, but they didn't appear too bad considering their age, etc. I could not locate a small or minute tear on either one.

So, unless you've read my earlier post, you will recall the entire back end lost air on 3 different occasions, before I got around to replacing the air bags. So far, after about a 10 day period, all still appears well.

It just seems odd to me that BOTH bags were leaking. Am I correct in my thinking that if ONE bag has a leak, it will only affect that side of the truck OR are both bags somehow tied together and if one leaks, the other will also loose air as well? I'm thinking that EACH solenoid seals off its respective air bag and that air bag can only loose air if their is a leak OR the solenoid is commanded by the computer to release some amount of air.

 

[Mike Joros]

YES, both sides of the suspension are connected together through your 20+year old hoses and valves.

Next time you have a leak in (2 weeks from now) listen to what other users are saying and change to coil shocks. These things are notorious for leaking (it is a money pit). I played with my air suspension for 1 year and $1K later switched to coil shocks. Definatly not worth fixing air ride on these old trucks unless have a backup vehicle and unlimited time fixing them. You will see.. some other hose or valve or master pump o rings will dryrot or give out shortly...

 

[NDNplanner]

Just this last weekend I took my kids off roading into the desert to look for jack rabbits, lizards, snakes and such. We came around a blind corner and hit a big pit of sand which stopped us in our tracks. This would have been no big deal under normal circumstances however my self leveling air ride shocks made the situation worse as my Expy decided it needed to level itself out and sunk the rear end all the way down to the frame leaving me even more stuck then necessary. After hours of shoveling i was no better then where I started. Luckily a kid came by in his F-150 and pulled me out after being stuck in the sand for a few solid hours after sun down. The second I got home I ordered an air-to-coil conversation kit off Amazon.com for my rear axle and have been happily ever after ever since. A few days later after I got everything converted over we drove back out to that exact same spot and redeemed ourselves with the gods of 4x4. My lesson learned to pass onto others... ditch the air ride and go with the tried and true coils. You will never regret it.

 

[nobycane74]

Looking for someone who might be able to help with a rear air suspension issue:

1- Purchased 1998 Expedition new - has 120K actual miles
2- Exceptionally maintained and garage kept
3- Never wrecked or in an accident

About two weeks back, the rear end was drooping because both air bags had "leaked" down.

Started truck and rear of truck immediately came back up to its proper position (so pump is functioning)

Let truck sit for two days and all was still well!!!

Then drove truck to town and back - the morning after, all appeared well. However that afternoon the rear end was drooping once again. Started the truck and the rear end of truck came back up to its proper position.

Then everything went well for almost a week and then the rear air suspension lost air once again. Starting the truck resolved the problem once again.

Obviously, something is failing. Has anyone else experienced this same issue?

I may have to wait until things get worse, but what is the most likely culprit?

Thanks so very much!

To be honest OP and a lot of people here are giving great advise, so I will piggy-back some of theirs as well....
MY 01 EXP EB (2WD) had the air suspension leveling system too...mine eventually just gave out due to age about 4 years ago at 79K. As being the original owner, it was way to costly to replace the system as it is.
So I converted over to coils like a lot of people have done....and trust me (and others) it was well worth it, the ride becomes a lot tighter, sturdier and nicer all around. It makes a lot of sense why FORD ended up getting rid of Air Suspension Leveling Systems on the Expeditions in early 2000's...they were a PITA and kept failing earlier on.