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Hello USMB, I need help with GL-10 Air Suspension


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Hey guys, new member here.  I recently aquired a silver 87 GL-10 turbo wagon with air suspension and the 3 speed automatic.  I essentially got the car for free so I figured if it ran, I'd spend some time and a little money trying to get it running good so I'll have a winter car.  It sat for probably 2 years, at least, up in the woods of the northwest.

Encouragingly the car started right up with a jump, and it actually drove over 180 miles down to where I live without any needed repairs.


So far, the problems I’ve found with the car are limited to the push-button 4WD not engaging( which may be a bad button is all) and more importantly...the air suspension will not lift the car.


When I turn the key to ON, the compressor starts running and continues to do so for about 8-10 minutes then shuts off.  After it shuts off, the light begins to blink on the dash indicating that there is an error.  I’ve found very little technical information on this system that I can effectively use to properly troubleshoot the problem.
The little that I have found has informed me that the behavior I just described usually occurs when a leak is present in the system.  Because the ride height does not change after 8-10 minutes of the compressor running, the computer assumes there is a leak so it shuts off and projects an error code to the driver.


I also read somewhere( and I could have this wrong, please let me know) that the computer will always try to raise the rear of the car BEFORE the front.  So, with this in mind I removed the plastic and carpet from the back of the car and checked the air lines for holes.  I found out that mice had literally severed the air line going to the passenger-side rear wheel.  I bought a couple air-line bridges(blanking out on what they’re actually called) and patched the line.  As of right now that’s the only defect I can find in the air system.  After fixing that though, the system still does the same thing.  It runs for 10 minutes without any change in elevation, and then shuts off leaving me with nothing but a blinking dash again.


What I’m hoping for is for someone who has had experience with these air systems to suggest some things to try.  Or that possibly someone who has a technical shop manual for the 80’s GL’s could take a gander at the pages detailing air suspension troubleshooting and post some suggestions...maybe even some scans :)

One observation that I’m not sure is important, is that my dad unhooked the middle hose from the compressor that goes to the tank.  We noted that he was able to blow air INTO the compressor...which seems like something irregular.  But I’m not sure.  Maybe it needs a new diaphram?


Help me out.


Oh and before everyone starts chiming in saying that I should just tear out the air suspension.. I’m not going to put that much work into this car lol  Plus, everything seems to be in good condition, the car has 150,000 miles.


Thanks in advance guys. 

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The system could still has a leak somewhere but I think the problem is the compressor is just worn out. Still runs but no air pressure to amount to anything. Had the same problem years ago with an XT6. Easy way to test all the struts for leaks is to jump each solenoid and apply compressed air from a reliable source. Just jump 12 volts to on side of the solenoid. When the strut inflates, only takes seconds, remove the 12 volts and the solenoid will close. Use a split plastic straw to remove the upstrream air line. You don't want to break those little locking tabs. 

 

Just from memory that center hose is the one that pressurizes the tank. Compressed air when needed flows from the tank, through the compressor manifold and then to each strut. The tank has a pressure switch. Designed to activate the compressor when the tank pressure is low. Once I worked out the bugs in my system, loved the ride and never considered switching to conventional struts. 

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Try wiggling the lines where they connect on the struts. there are 2 o-rings, which wiggling them sometimes makes them seal. try some silicone grease on them. There should be a height sensor in the rear struts, check the connections.

 

Should the struts themselves be failed, you can retrofit conventional springed struts in their place. There are probably no more oem NOS stocks available anymore

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I just junked mine... SAD.............as everything was perfect right down to the turbo and five speed and lock in front diff.. Just the whole under carriage was swiss cheese and I say this lightly.. The North East and it's climate eat Subarus for breakfast, lunch and dinner... My short comings.. should of hot hydraulic oiled it before setting it aside to fix my McLaren...

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The system could still has a leak somewhere but I think the problem is the compressor is just worn out. Still runs but no air pressure to amount to anything. Had the same problem years ago with an XT6. Easy way to test all the struts for leaks is to jump each solenoid and apply compressed air from a reliable source. Just jump 12 volts to on side of the solenoid. When the strut inflates, only takes seconds, remove the 12 volts and the solenoid will close. Use a split plastic straw to remove the upstrream air line. You don't want to break those little locking tabs. 

 

Just from memory that center hose is the one that pressurizes the tank. Compressed air when needed flows from the tank, through the compressor manifold and then to each strut. The tank has a pressure switch. Designed to activate the compressor when the tank pressure is low. Once I worked out the bugs in my system, loved the ride and never considered switching to conventional struts. 

Thank you much for the information.  I'm planning on doing the test you suggested today to see if there are leaks.

Couple more questions if you have a moment  to answer.  The solenoid that I hook up power to, it's on the strut correct?  Meaning that the test is checking to see if there are leaks in the air bags themselves.  Could I possibly, if I wanted to check the integrity of the entire system, unhook the middle hose from the compressor and blow air to all four struts?  Or possibly do each one at a time so i can have 12 volts hooked up to the strut but apply the air to the hose right where it comes out of the compressor.  The goal is to test the air lines as well.

I don’t know if that would work or not, let me know.

Also, if after checking the integrity of the airbags and air lines, I find that there are no identifiable leaks...I would then conclude that it’s the compressor?

And if it’s the compressor...is there a part for the compressor that I can just replace?

Or did you have to buy a whole replacement compressor?

 

Thanks again for all the info guys.

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any EA82 struts swap right in.  but the air struts do perform great when working properly.

 

* easy solution is to install an adapter on the top of the front air struts and inline with the rear strut air lines so that you can simply air them up with a compressor.

 

sometimes jacking the car up off the ground so the air bags can extend will get the system working properly.  though yours seems like it probably has issues from sitting.

 

front struts can leak - they typically leak where the lowest part of the air bag rolls over on itself and up against the strut body.  if there's any corrosion or rust on that part of the strut it'll wear through the air bag and leak.  jack the car up and get the struts extended to look for rust, corssion, debris, warn air bags, leaks.  it's a good idea to clean, sand, and paint that area if necessary to prevent it from happening. only have to do it once really.

 

the compressor is prone to:

1.  wearing out

2.  the plastic fittings on the drier (built into the compressor) crack at the base, bleeding off any air pressure

 

#2 is the most common problem i've seen on subaru air suspensions.  i find it hard to get good condition driers with those plastic fittings not cracked.

 

there are also 5 identical orings on one side - all air lines and one larger oring connecting the integrated drier into the compressor.  they can leak as well.

 

in general you get a used compressor and replace yours if it's bad (John got one from me for instance).

 

if it's not the compressor an oring or solenoid may be leaking (or another air line you haven't traced down yet).

6 orings on the compressor, one on front struts, 2 at each front solenoid, 1 on each rear solenoid air line, and the air tank has air line and pressure sensor orings on it.

Edited by grossgary
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specifically for compressor - verify first if it's the compressor or drier fittings cracking.  you won't be able to distinguish between the two until you remove it and look.

 

but yes, just replace it.  get a used one, new would be insanely expensive.  someone on here may have one, i've got a few XT6 units that are probably identical.

 

or www.car-part.com

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Thank you much for the information.  I'm planning on doing the test you suggested today to see if there are leaks.

Couple more questions if you have a moment  to answer.  The solenoid that I hook up power to, it's on the strut correct?  Meaning that the test is checking to see if there are leaks in the air bags themselves.  Could I possibly, if I wanted to check the integrity of the entire system, unhook the middle hose from the compressor and blow air to all four struts?  Or possibly do each one at a time so i can have 12 volts hooked up to the strut but apply the air to the hose right where it comes out of the compressor.  The goal is to test the air lines as well.

I don’t know if that would work or not, let me know.

Also, if after checking the integrity of the airbags and air lines, I find that there are no identifiable leaks...I would then conclude that it’s the compressor?

And if it’s the compressor...is there a part for the compressor that I can just replace?

Or did you have to buy a whole replacement compressor?

 

Thanks again for all the info guys.

Thr front solenoids are located on the firewall side of the strut towers. Rears are part of the strut. Think of the solenoids as faucets. When open, air flows from the compressor tank to that individual strut. When closed the air is trapped in the strut. You could apply pressurized air at the compressor fitting but will prove nothing if the solenoids are not open. Best way IMO to check each strut is to open the solenoid for that strut and apply air from another source. If the strut inflates and stays inflated, you know the strut and solenoid are good. The way I finally figured out my problem was a weak compressor is I removed the airline at the strut and with the compressor running, you can hotwire it at its relay, and held the line near my cheek. All I felt was a wisp of air, not what I expected. I probably could have generated greater pressure blowing through a straw. 

 

Another idea: Use some sort of pressure gauge at the compressor and verify how much pressure it is generating. Don't have a FSM anymore but maybe someone knows what its output is rated at. 

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Alright guys, again I want to thank you for the growing amount of information.  All of it is helping.

 

I have an update:

 

I unhooked the air line that connects the compressor/manifold to the air tank from the air tank and put pressurized air through the entire system.  When I did this I heard a loud hissing from within the car. Ended up finding another place where mice had completely severed an air line.  I didn't find it before because it was located in a place between metal and plastic that I thought was to tight for a mouse to get to.  Won't make that mistake again lol.

Anyway, I bridged it and then tried turning on the compressor again.

What happened was I was sitting for probably 5 minutes next to the car and didn't think I saw any difference.  Discouraged a bit, I pushed the height button to see if anything would happen and when I did...I heard a bunch of air go..somewhere.. and then saw the rear end lower.  

At this point I got all excited because the car had indeed lifted.

 

Anyway, fast-forward to now and the situation is like this.  Last night I drove it to the store and when I got there and turned off the engine the car was tilted.  The passenger side of car seems to lift, albeit slowly, and actually hold some amount of height.  While the drivers side does not.  Also, although I have not thoroughly tested this, pushing the height button while the car is trying to lift seems to quickly bleed air out of the system.  I have no idea why seeing as pushing the button is supposed to raise the car.

 

I also sprayed some soap water on the compressor where the 5 air lines come out and 1 maybe 2 of them slowly bubbled.

 

Any theories? 

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K so i got up this morning and both rear struts were pumped all the way up and held all night.  I also stood on the back bumber and pumped them down a couple times and they seem to hold.  What's weird is that when I push the height button, they seem to almost completely depressurize.

 

I'm stripping the rest of the interior tomorrow(mouse spoob and piss), so I'll check the rest of the lines, oil the seals and run some more tests.

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cool, getting closer!

 

*** have you tried jacking the front suspension up off the ground?  this sometimes gets air struts to air up that otherwise won't. 

 

how did you pressurize the struts from that line?  that's awesome!  like what attachment or otherwise did you use?

 

air isn't getting to or staying in the strut - i'd find that leak and i don't think the depressurization points to anything to help diagnose that.  that could just be some fail safe, limp home mode it does when it sees height sensors not adding up.

 

if you have air struts that won't air up and bubbles indicating leaking fittings - why do you not suspect that's the issue?

we can't see the car so we're limited in scope but seems like a good place to start - there's a symptom and there's a leak...

 

if it's of the 5 connections at the drier assembly, they each have an oring.  replace the orings.

or if that plastic fitting is cracked i've thought in the past some kind of epoxy or high quality marine grade sealant/adhesive  might hold.

 

the orings are removed with careful use of screw drivers pliers or build a tool. think of a straw that's cut down it's length with a slot so the straw can "open up", like the letter C as a cross section.  snap it over the air line - then press down into the 4 fingers of the tabs holding the air line in place.  i have one made out of plastic, very handy to have for those tabs which can easily break off.

 

i suppose to test you could swap the air lines if you suspect the fittings - swap two and two, the two "good ones" with the two "bad ones".  if the fronts then pump up and the rears do not, then that may indicate the fittings as the issue....seems like you'll find the leak another way though.

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Hey guys, well I'd like to think i finally diagnosed the problem with the Air Suspension and it's as one of you suspected.  The compressor would seem to be shot.

 

https://skydrive.live.com/redir?resid=DFD1989804E0C97C!963&authkey=!APlFqHEdTBB50q4

 

The above link is to some pictures I took with my phone of the compressor and dehydrator. 

 

The picture of the inside of the compressor is AFTER I blew out a ton of packed dust and rust out of it.  Soooo I'm thinking maybe I can get away with a rebuild kit.  Or I'm going to need a replacement.

 

So if anyone knows where I can get a rebuild kit for this and posts a link, much thanks to you. 

 

Also, if anyone here has a good condition/working compressor assembly that they can sell me, let me know :)

Edited by Turbone
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i've never heard of a rebuild kits. i've disassembled them before and they are so weak in design i doubt they have rebuild kits.  you can probably simply just clean everythign up and put it back together, make a gasket out of that sheet gasket you cut to shape yourself if need be.  though i don't recall there being a gasket.

 

paypal $42 to my username here at yahoo.com and give me an address and i'll ship one next week.

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I just junked mine... SAD.............as everything was perfect right down to the turbo and five speed and lock in front diff.. Just the whole under carriage was swiss cheese and I say this lightly.. The North East and it's climate eat Subarus for breakfast, lunch and dinner... My short comings.. should of hot hydraulic oiled it before setting it aside to fix my McLaren...

 

Junked it?!?! Wtf, I'd given you a couple hundred over scrap prices and picked up...

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Hey guys, I decided to put the compressor back together without the the dehydrator beads and without all the stuff that was plugging all the airways to see if the car will jack up. Any idea where this larger spring goes? I have two springs that were part of the compressor unit and I don't remember how or where the bigger of the two fits into it.

 

picture of what I'm talking about in link.

 

https://skydrive.live.com/redir?resid=DFD1989804E0C97C!982&authkey=!ABtYTvG9Qo96yf4&ithint=folder%2c.jpg

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  • 3 weeks later...

Hello fellow USMBites. So bit of an update on the car.  I bought a new compressor from Gary, got it in the mail, jerry-rigged some dehydration pellets in a stocking within the dehydrator/air-distributor, and started up the car.  No candy :/

The car still isn't lifting.  

I'm almost at the point of selling it to be honest.

Winter is officially here where I live, the nights are below zero and the snow is going to be here any day now.

 

Anyone got any last suggestions? 

Edited by TurboAir
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My only guess at this point is the individual solenoids aren't opening. The solenoids have to be open for the air to reach the struts. Underneath the door sill, driver's side, there is a control unit that activates the solenoids. I have a couple and Gary also probably has some. PM me your email address  and I can send a few photos of the control unit.

 

Another option is all 4 solenoids are frozen. Not very likely. 

Edited by john in KY
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  • 3 weeks later...

Alright, this is what I got guys.

 

Hooked up 12 volts to all four solenoids and, as far as I can tell, they all work.

 

I also hooked up a test light and identified that there seems to be power going to both rear and front solenoids even when the key is off.

When i turn the key on, the light on the test stayed on.

 

I've also seemed to identify( or more confirm) that the front struts are closed when i turn the key on.  I say confirm because the book says that the computer will always try and raise the rear of the car first.

 

I had the key on and applied 12 volts to one of the front solenoids and air started going into the front strut.

 

 

 

What I'm trying to figure out is that....if the solenoids work, the compressor works(i'm assuming it was good as I bought it from a USMB member and it turns on and runs), the o-rings are greased, and the bags hold air.....why the hell isn't the car going up?????


I did find some water when I unhooked the front airlines where they hook into the solenoids......which could be from running the air system with the dehydration unit being fucked (as it was).  But i haven't found anything that seems to be messed up.

 

 

I've never had exposure to a working pneumatic system before...if I unhook an airline while the compressor is going should it be blowing out with tons of pressure??? or is mine normal (being that I can easily hold a thumb over an airline even though air is passing through it).


Any last ideas guys? 

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if you need the vehicle to run - honestly you should convert to coil overs.  air suspension is not worth it for most people.  it's often like this - troubling to troubleshoot. 4 readily coil overs struts and you'll never be here again...it's the best option for most people.

 

1.  when you put the key in - does the air compressor turn on?  it should fire up immediately on a dead system...

2.  how long did the compressor run the first time you started the car?

3.  jack the car off the ground while airing up the steruts.  this can get the struts to extend after being slammed for a long time.

 

once you removed the old compressor, you're positive you installed the one i sent you?  that has happened before.

 

the pump should be fine but anything is possible on a quarter century old part.

 

*** You said you heard air moving when applying 12 volts to a solenoid...so that means the compressor is getting air into the tank.

But it may not be enough.  I'm not sure how to test that...

 

I'm curious for you to answer #2 above - when you first started the car what happened?  compressor turned on...for how long....then what...any blinking lights after 10 minutes?  the compressor shuts down after 10 minutes as an overheat protection. 

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I have two different pieces of hardware to manually inflate the struts: 

1.  is simply an adapter that threads onto the top of the front struts and then a schrader valve fittings screws on top of that.  so you simply have a schrader valve (think tire) that you can drive right up to any air compressor and fill the struts with. 

 

2.  the other is an inline Tee - you cut the plastic air line and each end of your cut line screws into compression style plastic fittings - and there's a T at the top with a schrader valve as well.  again - simply use any air compressor to air up each strut.

 

I can't verify size or part number but mine (#2 above) look exactly like this:

http://www.amazon.com/Monroe-AK18-Air-Shock-Accessory/dp/B000CD5QHM

 

doing a quick google search shows another option:

http://hildstrom.com/projects/easrd/index.html

 

basically - just splice into the air line at the front strut to get a direct way to air up the struts. The T fittings are nice because then it doesn't disrupt the stock system while you work on it.

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- Yes

 

if you need the vehicle to run - honestly you should convert to coil overs.  air suspension is not worth it for most people.  it's often like this - troubling to troubleshoot. 4 readily coil overs struts and you'll never be here again...it's the best option for most people.

 

1.  when you put the key in - does the air compressor turn on?  it should fire up immediately on a dead system...

2.  how long did the compressor run the first time you started the car?

3.  jack the car off the ground while airing up the steruts.  this can get the struts to extend after being slammed for a long time.

 

once you removed the old compressor, you're positive you installed the one i sent you?  that has happened before.

 

the pump should be fine but anything is possible on a quarter century old part.

 

*** You said you heard air moving when applying 12 volts to a solenoid...so that means the compressor is getting air into the tank.

But it may not be enough.  I'm not sure how to test that...

 

I'm curious for you to answer #2 above - when you first started the car what happened?  compressor turned on...for how long....then what...any blinking lights after 10 minutes?  the compressor shuts down after 10 minutes as an overheat protection. 

- yes the compressor turns on as soon as I turn the key on(not when I just put the key in).  What do you mean this happens on a " dead system"?

-The first time (and everytime after that) the compressor ran(runs) for 10 minutes and then shuts off, followed by the blinking error light on the digital dash.

 

- I'm sure I put the compressor in that you sent me.



After all this i may just convert to coils :/ .... I just thought it would be nice if I got it going.

 

In the event that I do go the coil route, does anybody have a link to a step by step guide to converting a pnuematic suspension to coil over??

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