My daughter borrowed my 98 Expy today and called to tell me that she returned to it and the back end was all the way down to the stops. I thought, no problem, I have been planning to replace the rear bags because they were original and I have a new set of Arnotts anyway. I decided to go through the regular checks and determined: The coupler under the master valve is good, the y under the spare tire was good, I jacked it up and also sprayed the bags - also appears good. Rather than have to run the pump all the time while checking (and waiting during the cool off time-outs), why couldn't I first determine if it was the front or back by removing one hose at a time from the dryer (plugging the open port), turning on the key while in 4wd lo and see if one end of the car will raise to the proper height. I did just that and nothing happened on the 1st hose, but noticed air escaping from the other. I switched hoses to pressure it and also nothing, and noticed that NO air was coming from the disconnected hose. I'm thinking that vehicles that only have rear bags only have 1 hose to the compressor. Ant ideas as to why this is happening?????

Another question - could I remove both hoses from the compressor, get a couple compression fittings and attach to my shop compressor, regulating it to 50psi. What is the maximum pressure I should use? This would provide a constant (and quiet) air source for troubleshooting. Would this work? I realize that I would need to leave the key in run position. Can I skin back the outer black covering to expose more white tubing or is the white tubing just a short piece? I don't want to create a situation where I consume some for the compression fittings and not have enough remaining to insert into the compressor dryer.

Your thoughts and ideas are GREATLY appreciated.

 

Gentlemen,

Any thoughts? I have made some time to work on it this afternoon and would appreciate your thoughts!

 

I got some compression fittings and attached bothelines to my shop air. Nothing happened at first and after several reconnections of the battery, the rear finally came up. I jacked it up in the rear, sprayed everything with soap water and can find NO leaks. I let the back end down and now it is WAY high.

It's beginning to make me wonder if it's an air leak after all. Thinking back, we took to the coast several weeks ago and twice the "check suspension" light came on. To get it to function again, all I had to do was to cycle the ignition switch and everything went back to functioning normal.

Could I have a problem with the rear height sensor? Or something else? How can I test it? Where do I go from here?

 

check the ride sensors...
There is also a tank like device on my 99 behind the left wheel.

 

Thanks Mark. Does anyone know the test proceedure for the ride sensors?

 

I have used but working spare ride sensor, I'll be willing to swap for your used rear bags once you install your Arnotts bags. My bags are fine, you dont need to rush.

Let me know and I'll ship them to you tomorrow (assuming you're in CONUS).

 

How about the relay behind the front bumper on the passanger side. With resetting the system and it working it sounds like it might be electrical. The relay is expensive but I don't know if there is a good fool proof way of checking them. The plug for the relay has been known for melting.

 

OP, if you search, I've seen members here who somehow bypassed the relay to 'jumpstart' the compressor, and deduce if the relay is in fact the issue.

I understand the relay is expensive, not sure about the sensors, but I have two of them (got it from a member who converted to conventional suspension set-up), so I can let go of one. I also have the new design spare connector (the one in the engine compartment which is the usual culprit for leaks causing the rears to sag, but I understand doesn't seem to be op's issue per his post).


Good luck.

EDIT: Realized I'm replying NOT to the op but somebody throwing an idea lol, so edited my post above accordingly.

 

Omahastro1 and Orleec - Thanks for the reply.

I can't come to reason with how it could be the relay as the compressor has been running what I believe to be properly. The delays I mentioned was also evident while I had the shop air attached, regulated to 65psi. If I'm overlooking something, please set me straight.

Bypassing the relay is very easy. Disconnect the plug at the relay and jumper together the 2 LARGE wires in the plug.

Also as a fyi - using shop air to troubleshoot works excellent. I made an adaptor (T) and attached an air line. Because I consumed some of the white inner line for the compression fittings, I had to skin back some of he black sheath to expose more tubing to reinstall into the Expy compressor/dryer.

Does anyone know the test procedure for the ride height sensors?