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Please help: Air suspension/compressor solenoid


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22 replies to this topic

#1 hammer008

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Posted 27 August 2004 - 07:34 PM

Problem: 1990 Subaru Legacy LS Wagon AWD.

My rear suspensions are flat with no air and the compressor is pushing air through but not enough to inflate the suspension. I just checked the compressor and the selenoid where the 5 air hoses come together looks cracked :banghead: and there is a small leak.


Can one buy just the 5 air hoses selenoid or should I buy the whole compressor?

#2 The Dude

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Posted 28 August 2004 - 07:42 AM

[quote name='hammer008']Problem: 1990 Subaru Legacy LS Wagon AWD.

My rear suspensions are flat with no air and the compressor is pushing air through but not enough to inflate the suspension.


I'm sure that someone who can really help you will post later. In the meantime, let me say that others in your position have REMOVED the air suspenstion system and replaced it with traditional struts. It would probably cost you more than the value of your entire car to repair the air inflation, IF you could even find the parts. So, unless you are a weathly eccentric guy with a lot of spare time on your hands, wait for someone to post specific conversion details.

#3 hammer008

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Posted 28 August 2004 - 10:44 AM

Good news and bad news...

1. I have managed to lock the air in the struts by removing the 2pin electrical connector and removing the air hose attachment.


problem::::::It just goes HIGHER AND HIGHER about to explode!!!! because of the heat generated by the struts. It is SCARY. So I guess the compressor also controls the maximum pressure.

This air suspension is has really beaten the heck out of me. I just wanted my original Subaru...I not sure if I have any more money to get regular struts....have to save for tuition.

#4 hammer008

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Posted 28 August 2004 - 11:36 AM

Good news and bad news...

1. I have managed to lock the air in the struts by removing the 2pin electrical connector and removing the air hose attachment.


problem::::::It just goes HIGHER AND HIGHER about to explode!!!! because of the heat generated by the struts. It is SCARY. So I guess the compressor also controls the maximum pressure.

This air suspension is has really beaten the heck out of me. I just wanted my original Subaru...I not sure if I have any more money to get regular struts....have to save for tuition.



To prevent explosion, I put the 2pin connector back and reattached the air hose. It went down...thank goodness. Although the suspension is at the right height, the ride is really rough.

I am now thinking of getting regular struts.

#5 canajun2eh

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Posted 29 August 2004 - 06:30 AM

I think your problem might be that the O-rings that seal the air lines to the solenoid valves need to be replaced. They will get hard with age.

When you replace the O-rings, you need to apply a little grease to them to help with the air seal. You can use Lithium grease or even Vaseline. You should apply grease to the O-rings even when you've not replaced them and have just removed the air lines to inspect things.

I believe you need 18 O-rings to do the whole system. 2 at the back, 6 in the engine compartment, 4 for the drier end of the air lines to the struts, 2 between drier and discharge solenoid on air tank. Your dealer can order them for you, or you can try to get similar ones from a local parts source.

The bulk section of my local hardware store has O-rings that are the correct size. If you can't get an exact match (4 mm diameter), get ones that are a little smaller -- 5/32" is close enough and is a standard US size. Thickness isn't all that important either. Specialty stores that deal in fasteners or plumbing supply places might also have the O-rings in stock.

You should order the air line removal tool while you're at the dealer. This little plastic thingie really makes things a lot easier. Subaru part number: 926520000. I use this on my XT6, but I think it's the same one for your Legacy.

#6 hammer008

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Posted 29 August 2004 - 08:36 PM

Thanks that is a great reply. I opened up the wheel well to change the 0 rings and lo and behold...the fasteners for the air hoses are all cracked!!!!! Do I need a new compressor...it seems to be pumping and there is air coming out..Do I need a new tank as well???

#7 canajun2eh

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Posted 30 August 2004 - 05:38 AM

If the plastic fingers of the air line connectors are cracked, you definitely should use the recommended tool. This tool is designed to spread the fingers evenly and just enough to allow the line to be withdrawn. If you use something else, you'll break the fingers for sure.

The tool I mentioned is similar to the ones made by Lisle and sold at Canadian Tire. http://www.lislecorp....cfm?detail=553 Unfortunately, the smallest in the set (5/16") is still too big.

You can live with one of the four fingers broken, or even with two as long as they're opposite each other.

Be sure to use grease when you put everything back together.

Be very careful when working around the tank. The pressure switch is fragile. I've managed to break two of them. They're still available from the dealer, but they're not cheap.

#8 hammer008

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Posted 30 August 2004 - 08:54 AM

Is changing the pressure switch easy to do? I noticed that the connector to the compressor is different from the rest?

#9 canajun2eh

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Posted 30 August 2004 - 07:07 PM

Yes, the pressure switch is easy to change. It just screws into the tank and is tightened with a wrench. It has an O-ring, and you use some grease on this. Why would you want to change the pressure switch if it's not broken?

I don't know what you mean about the connector to the compressor being different. Are you talking about the electrical connector?

The dryer (the thing with 5 air lines) is plugged directly into the output of the pump and is held in place by a spring clip. There's an O-ring (different from the rest) in there. Use grease. Always use grease when assembling any air suspension lines or devices.

When I gave you the count of 18 O-rings, I only counted the ones on the air lines. I didn't account for any of the others, since their sizes vary.

When you buy replacement O-rings, try to match the size as closely as possible. Don't buy rings larger than the ones you're replacing. In most cases, the slightly smaller ring can be stretched to fit. Thickness isn't critical, because the O-rings will be compressed anyway. Home Hardware, Canadian Tire, and Home Depot are all good sources for the O-rings.

#10 hammer008

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Posted 30 August 2004 - 09:14 PM

Yes, the pressure switch is easy to change. It just screws into the tank and is tightened with a wrench. It has an O-ring, and you use some grease on this. Why would you want to change the pressure switch if it's not broken?

I don't know what you mean about the connector to the compressor being different. Are you talking about the electrical connector?

The dryer (the thing with 5 air lines) is plugged directly into the output of the pump and is held in place by a spring clip. There's an O-ring (different from the rest) in there. Use grease. Always use grease when assembling any air suspension lines or devices.

When I gave you the count of 18 O-rings, I only counted the ones on the air lines. I didn't account for any of the others, since their sizes vary.

When you buy replacement O-rings, try to match the size as closely as possible. Don't buy rings larger than the ones you're replacing. In most cases, the slightly smaller ring can be stretched to fit. Thickness isn't critical, because the O-rings will be compressed anyway. Home Hardware, Canadian Tire, and Home Depot are all good sources for the O-rings.


Hmmm, Seems that the part where the 5 air lines come together is a bit different on my Legacy wagon. It looks like a deck of cards and is separate from the compressor.

ANyhow, I have taken your advice and replaced all suspect 0-rings with that great tool that you mentioned (thanks) and of course using silicon grease. Lo and behold the rear suspension rose to my glee!

But....the DArn front suspension stayed down???? Checking the front solenoid..found that they were not opening to allow any air in???? Can this be the computer?? or connection???

#11 canajun2eh

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Posted 31 August 2004 - 05:08 AM

On my XT6, there's a test connector near the driver's side (left) strut tower in the engine compartment. The 4 solenoid computer connections are available for testing here.

Since the computer grounds one side of the solenoid valve when it wants the valve to open, you should see 12 volts to ground on the test connection when the computer says "valve closed". This is so because the other side of the solenoid valve is always connected to to +12 volts when the ignition is on. If you don't see this, you might have a bad solenoid coil or a wiring/connector problem.

You can force the solenoid valve to open by grounding the test connection. That shouldn't hurt the computer. If this works, you know the valve is good. If it doesn't, the valve is stuck closed.

If the computer never calls for the valve to open, you probably have a bad electrical connection between the computer and the height sensor built into the strut.

I'm afraid I can't help you any further -- I don't have a wiring diagram for the Legacy air suspension system. I'm still trying to get my XT6 system to work properly.

Good luck.

#12 hammer008

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Posted 31 August 2004 - 08:38 AM

On my XT6, there's a test connector near the driver's side (left) strut tower in the engine compartment. The 4 solenoid computer connections are available for testing here.

Since the computer grounds one side of the solenoid valve when it wants the valve to open, you should see 12 volts to ground on the test connection when the computer says "valve closed". This is so because the other side of the solenoid valve is always connected to to +12 volts when the ignition is on. If you don't see this, you might have a bad solenoid coil or a wiring/connector problem.

You can force the solenoid valve to open by grounding the test connection. That shouldn't hurt the computer. If this works, you know the valve is good. If it doesn't, the valve is stuck closed.

If the computer never calls for the valve to open, you probably have a bad electrical connection between the computer and the height sensor built into the strut.

I'm afraid I can't help you any further -- I don't have a wiring diagram for the Legacy air suspension system. I'm still trying to get my XT6 system to work properly.

Good luck.

I opened it manually using 12V directly from the battery and now the suspension is as smooth as butter....it seems the ECU is not opening the front solenoids...so I guess I have to open them manually from now on...I just hope it does not leak because I don't like pumping the shocks with my bike compressor...someone told me that it will last for about 8-9 months...I hope so...in the meantime here are the diagrams that you may find usefull....AGAING THANKS FOR your help....could not have made the car drivable without your HELP!!!! :),
here are the wiring diagrams...

http://home.cogeco.c...1/soobpneu1.jpg
http://home.cogeco.c...1/soobpneu2.jpg
http://home.cogeco.c...1/soobpneu3.jpg
http://home.cogeco.c...1/soobpneu4.jpg
http://home.cogeco.c...1/soobpneu5.jpg
http://home.cogeco.c...1/soobpneu6.jpg

#13 spideyz

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Posted 01 September 2004 - 12:26 PM

My 89 with air struts had a self diagnostic setting that would flash a dash light with a morse code, like the EA82 ecu. Not sure if the Legacies have the same but it might. If you compressor is trying to fill the shocks then you shouldn't need a new compressor or tank. Good luck.

Keith

#14 hammer008

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Posted 01 September 2004 - 05:40 PM

My 89 with air struts had a self diagnostic setting that would flash a dash light with a morse code, like the EA82 ecu. Not sure if the Legacies have the same but it might. If you compressor is trying to fill the shocks then you shouldn't need a new compressor or tank. Good luck.

Keith

I don't know about the morse code...sometimes the button does not blink at all...

The compressor and the tank is good...what is problematic for me is the part that 5 air hoses come together seems a bit flakey...works sometimes when I spray some silicon or wiggle it...but not for long. Unfortunately they don't sell the part that connects the 5 air hoses separately from the compressor....at least at the dealer. Further, the "part" I was able to find in the junk yards were all cracked as well...oh well and don't want to dish out $550 for another compressor right now.

Forgot to mention that the ECU was not opening my front solenoids either...but I think that is because of a slow leak mentioned above.

#15 spideyz

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Posted 01 September 2004 - 05:44 PM

You should be able to convert to "regular" struts for less than $500. Way less if you can find a decent JY car to part out. No air shocks = no anoying problems. If the regular shock goes bad, your ride is just not as smooth as it might be until you can afford or have time to swap it out.

Keith

#16 hammer008

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Posted 01 September 2004 - 05:52 PM

You should be able to convert to "regular" struts for less than $500. Way less if you can find a decent JY car to part out. No air shocks = no anoying problems. If the regular shock goes bad, your ride is just not as smooth as it might be until you can afford or have time to swap it out.

Keith


Actually, I am driving happily now with "manual" pumping of each strut with a bike pump. So far I have driven about 300km without a problem...very smooth...smoother than my lexus es300 believe it or not nothing can beat an air suspension!!!...just disconnected the fuse for the compressor.

I am hoping that these air struts will last another 5 years since all 4 are relatively new. I just can't control the height or have any self leveling...small price to pay I guess.

#17 YAH93S

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Posted 15 September 2004 - 02:56 AM

So how did you go resolving this issue? I have a '93 Legacy (Liberty in Australia) and the front shocks - sometimes just one, sometimes both - are sporadically letting themselves down overnight (usually, seems to take ages).

I've just found this forum and have read some posts about the air suspension "issues" people have had. Haven't yet found one the same as mine, but plenty still to trawl through! If you can point me to any pertinent threads i'd be grateful.

I'm hoping it is going to be something more like your o-rings job than a replace 2 or 4 air struts job.

Cheers,
Leon
(March'93 Liberty/Legacy AWD 5sp GX wagon - my first subaru and loving it)

#18 86subaru

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Posted 15 September 2004 - 06:35 AM

well on my 88 turbo full time 4wd a/t wagon , the front drivers side had a hole in the bag so i replaced both fronts, now the back is leaking all the time , so i am going to replace the back with regular springs and shocks , because i have burned out 2 alt's , it is a real pain , alittle o- rings, which auto zone has a pk with 1 in it , good luck

#19 c150L

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Posted 15 September 2004 - 12:37 PM

Not sure, but the 5 hose solenoid you mention sound much like the black air dryer that is mounted to the outlet of the compressor. That is held on with 1 screw and one flat metal retaining clip. I may have one here I could part with. PM me if interested. I also have some PDF files that may help you repair, troubleshoot, understand your air suspension, but would need to email them to you.

#20 c150L

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Posted 18 September 2004 - 11:29 AM

So how did you go resolving this issue? I have a '93 Legacy (Liberty in Australia) and the front shocks - sometimes just one, sometimes both - are sporadically letting themselves down overnight (usually, seems to take ages).


Cheers,
Leon
(March'93 Liberty/Legacy AWD 5sp GX wagon - my first subaru and loving it)


Leon,

One thing caught my eye in your post. I have learned on my 89 XT6, that the fronts take forever to lift when totally flat. The rears will come up almost imediately. The fronts I took out of my XT6 (it's going somewhere, cheap!) are replacements and never leaked down. The ones they replaced, leaked down over night until I slimed them. This bought me about 3 more months before they blew out completely. Only thing I found to make the fronts go up faster was to jack that corner enough that the strut was just starting to extend. I would have to assume that the air inlet port, inside the strut, is partially blocked off when the fronts are totally compressed (retracted) by perhaps a rubber cushion that is built into them to keep them from bottoming out, metal to metal, when completely flat.

#21 hammer008

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Posted 19 September 2004 - 08:16 PM

Not sure, but the 5 hose solenoid you mention sound much like the black air dryer that is mounted to the outlet of the compressor. That is held on with 1 screw and one flat metal retaining clip. I may have one here I could part with. PM me if interested. I also have some PDF files that may help you repair, troubleshoot, understand your air suspension, but would need to email them to you.



The one on mine is completely separate from the compressor. It looks like a black deck of cards with a total of 6 attachments 1 from compressor, 1 from the air tank and 4 from the wheels.

#22 c150L

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Posted 20 September 2004 - 11:32 PM

Your black deck of cards, does it have electrical going into it? Is there another black bottle looking thing on the compressor that may be the air drier? Guess I have not yet heard of this type of distribution block as you have mentioned. (Can not think of anything else to call it. Deck of cards with 6 inlets I can picture though.)

#23 hammer008

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Posted 22 September 2004 - 12:13 PM

Your black deck of cards, does it have electrical going into it? Is there another black bottle looking thing on the compressor that may be the air drier? Guess I have not yet heard of this type of distribution block as you have mentioned. (Can not think of anything else to call it. Deck of cards with 6 inlets I can picture though.)



No electrical connectors that I can see without taking it out. Again, I am pretty sure the air hose coming from the top of the deck of cards is coming from the dryer.

Anyhow, I am happy now with my suspension...although I have to "self-inflate" with my bike compressor....but no big deal since it has not leaked any air so far and somebody mentioned it will last for about 9 months...before I pump the struts again. I could live with that.




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