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Rear Air Suspension Compressor Mod?

Discussion in 'OEM' started by Instrumental, Mar 6, 2016.

  1. Instrumental

    Instrumental Well-Known Member

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    I'm wondering if anyone has ever done or knows of a replacement compressor for the rear suspension. Maybe I should explain.

    Not shockingly I have a compressor that runs but no longer builds pressure. In looking for a replacement, I'm not amused by the prices. However, I keep seeing universal pumps in the 75.00 to 100.00 range, that's not so bad. Is is possible to rig one of these to work?

    Currently, I added a T and a schraeder valve to manually inflate the bags for my needs. I'd like to a tie a compressor into this setup be able to have more control over my ride setting, especially when towing, that's my biggest issue right now.

    So, I figure 2 options. 1st and most preferable, is it possible to use the wiring from the factory pump to control a universal pump? My thoughts are that the sensor is till in place, and if the computer is sending power to the pump to increase pressure, it can tell the new pump that. Not sure how the release of air to lower would work...

    2nd option, a simple switch I can control in the back. In this case, where's a good place to get power from? Also need to figure a vent option for this too, unless that's a feature the pump would have built in.

    Fire away!
     
  2. northcreek

    northcreek Well-Known Member

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    First you must realize that the brains of the air ride is in the compressor unit, it is a stand alone system.
    There is much here in past threads on all of your questions if you search.
    If you want to keep the air ride and not convert to springs I would suggest a proper replacement compressor unit. You will be hard pressed to configure a system that will function as well with no thought on your part...Mike
     
  3. Instrumental

    Instrumental Well-Known Member

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    Yes, I think I've read every post on here and quite a few on TV as well.

    I did not realize the brains were in the pump, that kills my first idea and does explain some of the high price.

    I figure I can't be the first person to experience this, just fishing for ideas.
     
  4. AWD V8

    AWD V8 Well-Known Member

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    Don't know if this helps but a coil spring conversion costs way less than just the compressor. You still have the bags that will fail, and possibly the level sensors.

    I don't regret my coil spring conversion.
     
  5. Instrumental

    Instrumental Well-Known Member

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    My problem with the coils is I tow several trailer of varying weights, and there's nothing better then the airbags for that.
     
  6. Sparky

    Sparky Moderator

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    I know some people have used helper bags in coil springs, but I don't know if that really makes much sense to convert to coil springs just to throw helper air bags in them when you've already got bags. Although, I guess with that setup you would normally run around with the bags depressurized, then only add air when towing.

    Aside from the OEM compressor setup I don't think there's much other option for an automatic system since as pointed out the brains are all in the OEM compressor. Maybe there is a why to retain the brains but just tap into the compressor power output that is normally internal and reroute to the new compressor? You would essentially have two compressors this way, although the original wouldn't be hooked up anymore aside from the brains part. Just a thought.
     
  7. Instrumental

    Instrumental Well-Known Member

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    Sounds like a good putzing around project. I think I'll rig up a manual system for now, just having the compressor built in will beat having to fire up the garage compressor and haul out the hose and whatnot every time I need to add air. Not to mention needing it when not at home...
     
  8. Wooluf1952

    Wooluf1952 Well-Known Member

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    Just a thought: Have you tried the outlet used for filing tires from the OEM compressor inside the truck?
     
  9. Instrumental

    Instrumental Well-Known Member

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    In what respect? I used it to check pressure, and I can't get it quite to 40 psi. It pumps air, but not enough pressure to move the fear end up.
     
  10. Wooluf1952

    Wooluf1952 Well-Known Member

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    OK. I thought if the compressor worked, maybe just the lines were bad and you could use the compressor to manually fill the bags.
     
  11. Instrumental

    Instrumental Well-Known Member

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    It holds air great with the schraeder valve I added, so the bags and lines are good to go.

    Gotta do some research on the pumps and controls for them. I don't want it to nickel and dime me up to the price of an OEM pump!
     
  12. therealsethallen

    therealsethallen Well-Known Member

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    I did a coil spring conversion back when I got my Saab in late summer of last year, My compressor works, quite well at that. If you want it I'd be willing to part ways with it, check your PMs.
     
  13. Instrumental

    Instrumental Well-Known Member

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    Picked up the following parts this weekend, gotta find time to install shortly.

    I have to say, I'm kind of getting to like the idea of the manual setup. We were putting a boat and jet ski in the water last weekend at a shallow ramp, so I pumped the shocks up nice and high to give a better angle to launch. Worked great!

    Anyway, here's the pump and a gauge/switch setup to control it. I especially like the release button to let the air out.

    [​IMG]

    [​IMG]
     
  14. therealsethallen

    therealsethallen Well-Known Member

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    I can't say I'm in agreement there. Maybe it's the sterotypical lazy American in me but I'd never want constant fiddling with my air suspension. I put in TrailBlazer factory suspension and never looked back.
     
  15. northcreek

    northcreek Well-Known Member

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    Looks like a nice retrofit .Wondering, what did the setup cost and where are you going to mount it?...Mike
     
  16. Instrumental

    Instrumental Well-Known Member

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    Well, I've had it with a Schraeder valve for a month or two now, and I rarely mess with it. Typically when I'm hitching something up to level it back out, and then release the air when I'm done back to normal ride height. Again, my towing needs make this important for me. If I wasn't, I could see the appeal of removing the bags.
     
  17. Instrumental

    Instrumental Well-Known Member

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    I'm about 100.00 in right now. Could be less then 70 without the gauge, but I like the convenience factor of the release valve. Planning to mount it in the compartment by the pump switch, it'll fit, so that's plan A.
     
  18. therealsethallen

    therealsethallen Well-Known Member

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    I tow my camper, I have helper bags in my coils.
     
  19. Instrumental

    Instrumental Well-Known Member

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    Got started tonight. Removed the compressor and the hoses running into the rear compartment so I could run what I need through there. Found the power i needed from the factory harness, then proceeded to blow the fuse I should have pulled by letting them come in contact with each other. Oops. Well, needed to bring it down to a 10 amp anyway.

    So, at this point I've wired and mounted the compressor, including the switch on my gauge. I need a couple of fittings to make the remaining connections, trip to the local store where the guys actually work on cars is in order, but at this point the hard stuff is done.

    [​IMG]
     
  20. northcreek

    northcreek Well-Known Member

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    Yeah but, wouldn't you want the control station up front with you? I have a similar setup on my motorhome and you will find that temperature and just driving will change the pressure, I often adjust on the fly....Mike.
     
  21. Instrumental

    Instrumental Well-Known Member

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    That WOULD be convenient, but then I'd have to run an air line and power all the way to the front, or find a place for the compressor in the front, more work that I want to deal with. I anticipate doing most of my adjusting after hitching up or when I unhitch. That'll do for me.
     
  22. northcreek

    northcreek Well-Known Member

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    Good point! :thumbsup:
     
  23. Instrumental

    Instrumental Well-Known Member

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    Just finished the job, got some great help from the local NAPA on the fittings I needed to get all the components to share air with each other. So far so good, holding air and easily adjustable as I hoped.

    [​IMG]
     
  24. Bow_Tied

    Bow_Tied Well-Known Member

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    Nice mod. How's it working?
     
  25. Instrumental

    Instrumental Well-Known Member

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    Wow, late reply by me! Working great, did a 3,000 mile trip towing a popup this summer, all good. Also did a few trips around Michigan towing boat, no problems. Found it convenient at a shallow ramp to put the rear end up higher in the air to facilitate getting the boat on and off the trailer. Can't do that with the factory auto level! (I'd still rather have it)
     
    Bow_Tied likes this.
  26. mfnman88

    mfnman88 Active Member

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    Hey. first post here. Just bought an 08' Saab with almost the exact same situation. Drove 45 minutes on no air. (only got the back end off the ground a couple times)
    You mentioned Michigan so I checked your profile. I bought mine in Canton and drove south almost to the border on 23. Your place was closer. lol. Thought you'd enjoy that.
    Anyway, just wondering if you had any quick insight as to max PSI for the bags, and if anyone knew how the ride height sensors were wired. I'm wondering if I can mimic your system but piggyback the power through those sensors so it would would act as a cut-off switch when I got to "stock ride height." That way I'd be able to have the switch up front since I wouldn't need to run the airline for a gauge.
     
  27. northcreek

    northcreek Well-Known Member

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    Those sensors are just that, they are not limit switches. They are relaying position information to the brains of the system which is located in the OE compressor. Mike.
     
  28. mfnman88

    mfnman88 Active Member

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  29. northcreek

    northcreek Well-Known Member

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    I don't know about the signal type but, remember that you have to bleed off as well as supply air to the bags.
    The OEM unit does all of this really well, if it were me I would ask Santa for a new compressor unit.:twocents: Mike.
     
  30. Johnnyringo

    Johnnyringo Member

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    Can't seem to find what year and model you're working on. Where is the compressor compartment in the photo located?
     
  31. therealsethallen

    therealsethallen Well-Known Member

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    His truck is a 2007 Saab 9-7x. The compressor compartment only has a switch and a fitting for the accessory inflator. On the Short-Wheelbase Trucks the Air Ride Compressor mounted to the frame rail above the resonator. The EXT/XL Trucks have it on the passenger side frame rail, although it is blocked by the spare tire.

    The GMT800 Equipped with the Autoride System have the compressor in the engine bay, again bolted to the frame rail. 2007+ GMT900 Style trucks don't have that system.
     

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