1998 Expedition 4x4 5.4L Eddie Bauer


Hello everyone,

I have searched the tech folders and the other posts regarding this issue but haven't found any technical assistance.

I have my father's Expedition (see above description) and the other day when pulling into the Coast Guard base, I was at the guard gate and suddenly I heard a loud air burst noise with a steady loud release of air. I jumped out and walked around the truck and all tires looked normal. I then jumped back in drove another 500 feet and parked. About three hours later I went back to the truck and the back end had fallen. I drove it home and jeez evey bump in the road was exaggerated and everything in the back bounced all over the place.

I have been reading other posts on here and it looks like it can be the rear air shocks, the compressor itself, or a hose line. I read about a soapy water test but wanted to ask do I spray the soapy water all over the air shocks themselves and along as much of the air hose I can see?

I haven't been under the truck yet, but will do this today. I read somewhere that the compressor is under the hood under the windshield fluid reservoir..is this correct? I had the window down then the burst happened and I think it came from the rear and not under hood. The switch for the compressor is behind the front passenger kick plate? Is that correct?

I will try to find a split in the air hoses or air shocks themselves. is it a hard repair? I saw online...maybe rock auto replacement air shocks without hardware for about $45 each and a kit made by Suncore? I don't know how much longer I am keeping this truck and figure I just want to replace the standard air shocks for now... if needed. Is it a hard repair to pull out old air bags and insert new ones? I imagine you pull out the deflated old ones and install the new ones while they are still deflated then hook up hoses to the new ones and hope your compressor fills them? Any suggestions or anyone done this already? Thanks in advance for any info, advice, or suggestions you can give.

One last thing.....the air compressor would kick in periodically while driving. It would usually fill the shocks when first started and for first 15-20 seconds then periodically while driving. Is this normal or is compressor only supposed to come on when first starting engine..... should it have held the pressure until shutting off truck again? Maybe that indicated that for a while I've had a leak somewhere. Any fuses or relays I need to check? I'm sure though with the air burst sound, it wasn't a relay or fuse.

Sincerely,
Andy

 

Just to keep the confussion down, the rear shocks on your Expy are not air shocks. They are conventional shocks. The rear of the vehicle is supported by the air bags.

I'd suggest that you get out and get under it so you can see what you have. The soapy water test you mentioned would be a good thing to do at the same time. You may not have as big of a problem as your imagination is painting.

And don't overheat the air compressor as that shortens its life and overheats the compressor relay. (That relay alone can ran $115 +).

 

The compressor should only come on when the truck is first started, or when switching to 4WD Low. The system should hold the pressure virtually indefinitely.

 

I have heard the compressor kick on long past start up. This usually happens when passengers are added/discharged or a load has shifted without shutting off the engine. This has been normal for my truck since purchase in 2003 w/ 25k miles.

I've been investigating the bag to spring conversion for a while in preparation for an air suspension problem with my '01. Just how bad (read expensive) a failure I experience will determine whether I repair the existing system or do the complete conversion.

One conversion kit vendor states that installing their product rates as difficult as doing a complete brake job. I've linked a video that demonstrates a rudimentary install. You can probably find a video specific to the kit you end up with.

 

I just completed an air to coil conversion on my 2000 Navigator. I bought a kit from Monroe that included springs / shocks for rear, and coil-overs for the front. It was $250 at Advance (they had it in stock), had I been patient, I could have ordered it online from RockAuto or shocks.com for right at $200. I didn't have time to do it myself, so I had it installed. Labor was about $250 for the complete job. Total conversion cost, including labor, was $500. I don't really notice much difference in the ride. I also don't tow much, so I'm not too worried about the load leveling feature, though if I did I'd likely just buy stiffer springs (which I'm sure would have a negative impact on ride quality). Overall, after a couple road trips with the conversion, I'm quite happy. Now, to get that pesky check suspension light to go off....

 

There was no mention of a change in driving parameters such as adding or deleting passengers. Changes to the weight on the suspension obviously will add or delete air from the system. I figured that was something overly obvious to even the most simple minded.

 

Thank you.