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.