Can anyone tell me where to start troubleshooting the air suspension on my 97 Expy....The compressor seems to be working fine because it pumps air back into them when i start it up, it just bleeds down after i have it in park.

 

They all do that. When the truck is off, the back sags back down. As long as the rear pumps up and stays up, you are OK. If the pump runs constantly after pumping up, then you have a problem.

 

Run it up to trim level....

Leave your car on then turn off the air switch at the far back Passenger corner.

Turn it off. It shouldnt bleed down like normal. If it does after sitting for a few hours/days then you got a leak.

 

It does bleed down when the switch is off. The problem i am having is, when i get home and park it it will bleed down in a matter of minutes and sometimes it doesn't bleed down at all....Other times it will bleed down and then a few minutes later it will pump back up and stay. I heard there was some kind of silonoid for or on the air bags that could go bad and cause the air bags to open and relaease the pressure ...any idea of what i'm talking about?

 

My 00 does the same thing. It starts to bleed down imediatley after I shut the truck off. I think it supposed to stay at trim level for abit after the truck is shut off. Everything else works just fine and my compressor doesn't run very long to pump up the system ( it's loud and I still have the original bushings and bracket so that's probably why) and once it's at trim level the compressor never kicks in again.

I was thinking I had a silinoid gone bad also but I don't want to start tinkering with the LLS because as I stated, it's working fine on my truck.

 

There is a solenoid on each of the rear air bags. They are replaceable and can be bought at the two suspension places that were posted in your other 2 threads.


In structions could probably be found in a search for solenoid replacement.

 

The suspension is supposed to lower the truck when you shut it off to allow for ease of exit from the truck.

 

Yeah but if you pump her up...shut off the switch under the dash. Itll hold pressure w/o bleed. You can sit it for a while or even drive it and check for leaks that way.

 

About the solenoids, I called strutmasters and they told me it was a dealer part. I called the dealer and they told me $89 each if they are located on the bags itself and $49 if they were located on the frame. I don't even know exactly what the solenoids look like to be able to see where they are....anyone have a pic or can explain what they look like....and also are they easy to change?

 

I have often taken the advice of the Forum, purchased the part, then looked for a part that matches the new one in my hand. Sounds cheezy, but has saved me hundreds of $$$

 

I'm assuming you all have 4-wheel LLS?

I have rear-only LLS and it doesn't bleed down at all.
It always maintains the same height.

 

No I have rear wheel LLS...I have another question...If i turn off the suspension switch and the truck stays lifted, does that mean i don't have a leak and my problem could be something other than a leaking connector,line, or bag...

 

If the rear stays up and the pump doesn't run to keep it up, it is likely that your bags are OK.

 

Every once in a while, on long road trips, the passenger side cut off switch will get bumped (feet, bags, luggage on floor, maps...) and when it does, the suspension light comes on; usually, this happens (to me, anyway) when I'm on a turnpike or highway and have to drive a bit to get over to the side of road and turn it back on. Point is, during that driving, even with a lot of cargo or people weight, the truck (4wd LLS) still stays pumped up with the switch off, which always suprised me, I would have thought it would have run down to the rubber stoppers, but it stays up. Another thing I have noticed (related to your observations) is that when I park the truck in the garage after driving it, if I lift the hood and listen carefully, I can hear the new compressor I put in last year start to bleed down a bit, a short hissing noise, sounds like air is escaping, but it only lasts for 15 sec or so, it must be normal because the noise stops and the truck settles level. Just some of the performance characteristics that I have observed. Seems to run fine, though. However, we are approaching a seven year old car (mine's a 2000) and I am not convinced that there are'nt some small leaks in those rubber bags in the back LLS part. The rubber can't stay viable forever. Haven't found any leask yet, but I'm buying a set of air bags just in case, from Strutmasters or whatever vendor everybody recommends here. Hope this helps.

 

well the compressor isn't going to run if i have the switch turned off right