The shocks or the air compressor? That is the question.
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Page 1 of 2 1 2 LastLast
Results 1 to 15 of 30
Cadillac DeVille 1985 to 2005 including:
1985-1992 Fleetwood, 1993 Sixty Special, All FWD Forum Discussion, The shocks or the air compressor? That is the question. in Past Cadillac Vehicle Discussion; ...
  1. #1
    zergkiller is offline Cadillac Owners Fanatic
    Automobile(s): Cadillac Deville 2001
    Join Date
    Jul 2007
    Location
    Carrollton, Texas
    Age
    70
    Posts
    127

    The shocks or the air compressor? That is the question.

    Iíve tried to read the shop manual about this, and Iíve tried to make some sense from the posts on this forum, but I just donít understand for certain how this air ride suspension works. One thing that Iíve noticed is that the air compressor pump on the car runs quite a bit, and I donít think thatís a good thing.

    But Iím sort of guessing that there is a control system that pressurized the shocks in the rear to accommodate a different weight, and the compressor pumps the shocks up to make that happen. There appear to be levelers on the system, and Iím guessing they are the sensors, but when I read the shop manual, and look at the comments on this forum, I get all kinds of different opinions. Some people replace the air shocks with other kinds for their own personal reasons that I do not understand. I donít think I care either, but whatever. There are conversion kits and so on, and all that does is confuse me to the point that I wonder what kind of shocks I should buy.

    Today, I put the car on ramps and looked at the shocks. They have a layer of oil and road dust on them, plus wear patterns that tell me the rattling that is also going on is probably them. With 130K miles on the car, it doesnít surprise me that I need new shock absorbers. What to do, what to do? There are no codes. Iíve looked under the car about the rattles, and donít see anything broken. All rubber looks good.

    I just really hate it when Iím guessing a solution. The pump seems to turn on when I have my foot on the brake at a light, for example, so Iím thinking ďmanifold pressureĒ, but that could be decades back in ideas. AnywayÖRockAuto shows this:

    DELCO Part # 504547 {#88946635} AIR ADJUSTABLE USE T/W 19210500 IF OE ABSORBER HAS THREADED FITTING; Universal Adapter Kit Included Threaded Air line ABSORBER,RR LVLG SHK 4 DOORS; w/4.6N/Y(LD8); TWO PER PACK, EXC ELEC ADJ SUSP

    But then, this looks good too:
    MONROE Part # MA822 Air Line, Fittings, and Fill Kit not Included
    Rear; With standard suspension

    Besides these, there are all kinds of other options that donít look a thing like the ones I see.

    Would replacing the shocks stop the compressor from turning on? Is the compressorís running related at all to the shocks? What are the mysterious ďair bagsĒ mentioned in some of the literature?

    Tune in later for the surprise answers, and the completely unexpected mystery guest.

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with DTS floor shift)
    Join Date
    Jun 2004
    Location
    Woodstock Ill.
    Age
    66
    Posts
    73,345

    Re: The shocks or the air compressor? That is the question.

    Replacing the shocks will stop the compressor from turning on so often IF the shock boot has a leak in it. That's the rubber bladder ("air bags") at the base of the shock. If the leak is in a line or fitting, no changing the shocks will not stop it. The compressor only pressurizes the rear shocks.

  4. #3
    Submariner409's Avatar
    Submariner409 is offline If it won't run, stick on fender vents
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    74
    Posts
    44,569

    Re: The shocks or the air compressor? That is the question.

    The "compressor" is part of the rear ELC - Electronic Level Control - a system which functions solely to maintain rear suspension ride height in the event of added weight in the trunk or rear seat.

    Depending on the year and model, rear ride height is sensed by one or two sensors which are either integral with the shock absorber or separately mounted to the frame. The sensors send control signals to the compressor assembly - compressor, drier/filter, and exhaust solenoid - in order to send/exhaust air through lines to bladders integral with the shocks. This action controls rear height: it is NOT "air ride".

    The compressor is subject to moisture corrosion due to condensation caused by compression heating and cooling - the filter/dryer is supposed to control this, but sometimes becomes saturated, thus pumping moisture into the air lines and shocks.

    The shock bladders rot over time. The air lines are sturdy but they do deteriorate, causing leaks. No part of the system depends, in any way, on intake manifold vacuum.

    The OP needs to diagnose the system, focusing on air leaks, and perform the necessary repairs. The posts concerning switching to aftermarket passive systems reflect the inability of the car owner to maintain the car to Cadillac standards, due to either financial considerations or pure ignorance.

    The correct thread title should be "The shocks and the air compressor".

  5. #4
    zergkiller is offline Cadillac Owners Fanatic
    Automobile(s): Cadillac Deville 2001
    Join Date
    Jul 2007
    Location
    Carrollton, Texas
    Age
    70
    Posts
    127

    Re: The shocks or the air compressor? That is the question.

    Quote Originally Posted by Ranger View Post
    Replacing the shocks will stop the compressor from turning on so often IF the shock boot has a leak in it. That's the rubber bladder ("air bags") at the base of the shock. If the leak is in a line or fitting, no changing the shocks will not stop it. The compressor only pressurizes the rear shocks.

    Well that straightens out a good part of the confusion. Thank you Ranger.

  6. #5
    zergkiller is offline Cadillac Owners Fanatic
    Automobile(s): Cadillac Deville 2001
    Join Date
    Jul 2007
    Location
    Carrollton, Texas
    Age
    70
    Posts
    127

    Re: The shocks and the air compressor? That is the question.

    Quote Originally Posted by submariner409 View Post
    The "compressor" is part of the rear ELC - Electronic Level Control - a system which functions solely to maintain rear suspension ride height in the event of added weight in the trunk or rear seat.

    Depending on the year and model, rear ride height is sensed by one or two sensors which are either integral with the shock absorber or separately mounted to the frame. The sensors send control signals to the compressor assembly - compressor, drier/filter, and exhaust solenoid - in order to send/exhaust air through lines to bladders integral with the shocks. This action controls rear height: it is NOT "air ride".

    The compressor is subject to moisture corrosion due to condensation caused by compression heating and cooling - the filter/dryer is supposed to control this, but sometimes becomes saturated, thus pumping moisture into the air lines and shocks.

    The shock bladders rot over time. The air lines are sturdy but they do deteriorate, causing leaks. No part of the system depends, in any way, on intake manifold vacuum.

    The OP needs to diagnose the system, focusing on air leaks, and perform the necessary repairs. The posts concerning switching to aftermarket passive systems reflect the inability of the car owner to maintain the car to Cadillac standards, due to either financial considerations or pure ignorance.

    The correct thread title should be "The shocks and the air compressor".

    Well, one of the hints I read said that if the compressor runs all the time, it burns out, so I guess I'd better get a wiggle on. The job looks pretty ordinary, but from the two choices I have, I don't know which is which. Besides that, there are various kits and things to buy, and I saw one of the kits had a recharging kit with it. Do you have to replace the dryer at the same time? Is it a good idea to do that periodically?

    Thanks for your response to now.

  7. #6
    mtflight's Avatar
    mtflight is offline Cadillac Owners Connoisseur
    Automobile(s): 1999 White Diamond ETC
    Join Date
    Jan 2005
    Location
    Dallas, TX
    Posts
    2,531

    Re: The shocks and the air compressor? That is the question.

    Hey Zergkiller, I'm not far from you. I followed your post on fixing the HVAC mode actuator (was very helpful). I recently had the same problem as you, and replaced the rear shocks. I also replaced lines, and replaced the front too.

    The system is VERY simple. There's a height level sensor at the rear driver side wheel well that commands the compressor off or on. The compressor is connected to a dryer canister (that is $30 refurb from suncore, and >$90 new) The dryer is connected to 2 lines that are very robust and don't leak UNLESS they have been cut or severely damaged. The usual point of leakage are the shock absorber boots.

    The news is the original rear shocks are no longer made, so you're left with basically 3 choices.

    1) AC Delco -- you will pay a premium only to discover they are Gabriel HiJackers with a sticker on them that says AC Delco. If your lines are damaged... you would need to buy a kit that Monroe makes, else the OE lines are $130 (don't even think of paying for them at that price).

    2) Gabriel HIJackers (what I got)--I even replaced the lines which were included in the kit that I got for $77 shipped. basically this is what AC Delco chose too, which influenced my purchase decision.

    3) Monroe MA822 (cheaper, but probably substantially firmer than stock).

    Replacing the shocks is easy as pie, diagnosing the leak is not. Replacing the lines is easy if you go with Gabriels--everything you need is in the kit--EXCEPT the 1/8" pressure fittings (you will need 2!). I got them at Elliot's hardware in Plano off Park and Preston.

    If you want me to take a look at it, I'd be happy to.

  8. #7
    zergkiller is offline Cadillac Owners Fanatic
    Automobile(s): Cadillac Deville 2001
    Join Date
    Jul 2007
    Location
    Carrollton, Texas
    Age
    70
    Posts
    127

    Re: The shocks or the air compressor? That is the question.

    @mtflight

    Oh, you must be that mystery guest!! I knew those other two. LOL. They are so helpful it's just plain monotonous.

    Thanks for the offer of help. That's too cool. I hope I can do this alone, but your information will probably solve the thing. From what I saw, there is only one air tube going to each shock, not possibly two as they show in the shop manual. I'll send an email for contact info.

    I know where Elliot's is. They manage to stay alive in spite of Home Depot by having all kinds of obscure things the big stores don't carry. Sometimes, they have really neat stuff for gifts too. You wouldn't ever find it by yourself.

    Watch for my email. When I get all the parts together, I'll just start working. First I get the info, then the parts and then the gumption to do the work.

    Thanks again.

  9. #8
    maeng9981's Avatar
    maeng9981 is offline Cadillac Owners Connoisseur
    Automobile(s): 14 SRX, 12 Sierra, 00 SLS, 99 Deville 50-year Anniversary
    Join Date
    Mar 2009
    Location
    Dallas, TX
    Age
    23
    Posts
    3,126

    Re: The shocks or the air compressor? That is the question.

    Off topic, but I am really glad that I see a lot of Dallas people in this forum. And it seems like we all have some sort of ELC problems....haha

    I also went through a new(refurb) compressor assembly and just diagnosed a leaky shock. Once I verify the correct part I will order them and they will be installed soon.

  10. #9
    zergkiller is offline Cadillac Owners Fanatic
    Automobile(s): Cadillac Deville 2001
    Join Date
    Jul 2007
    Location
    Carrollton, Texas
    Age
    70
    Posts
    127

    Re: The shocks or the air compressor? That is the question.

    Iíve had a couple of p/ms with mtflight about that. Apparently, there are two choices.

    Gabriel HiJackers, available here:

    http://cgi.ebay.com/ebaymotors/ws/eB...m=270639417317 for $72, shipped.

    They come with replacement pressure lines, and a spring that Gabriel says you must use in the dryer to make things work correctly. His idea of replacing the desiccant in the dryer is a good one, since if the shock leaks, there will probably be moisture in it and that could damage the compressor later. The Gabriels also have the wrong fittings on them, and you have to find the correct ones. He required them to mate the OE lines (2) out of the dryer to the Gabriel lines. He says they were nothing specialó1/8", but Lowe's only had 1/4Ē.

    Mtflight suggests using silica gel pellets or a kitty litter called "MiMi Litter" at Walmart for around $4 for the replacement desiccant. MiMi Litter comes in a blue bag with red writing (not at Wal-Martís, but at many). Another idea might be to put the stuff in an oven at 250 deg. F. for a couple of hours. The drier may be rusted together, and in that case, a vice and strap wrench is suggested.


    Monroe makes replacements also, without the pneumatic lines or the hassle of replacing the spring in the dryer. MA822 (Monroe) $55 shipped!! This is the link for them:

    http://www.amazon.com/Monroe-MA822-M.../dp/B000C55T7W

    So for myself, Iím going to disconnect the fuse for the pump until I figure all this out. I think Iím going to use the Gabriels, but that gives me a couple of problems like the fittings, opening the dryer and finding the desiccant. I donít want to open the car up on stands and then have to go get parts if I can help it. And I donít have a vice.

  11. #10
    mtflight's Avatar
    mtflight is offline Cadillac Owners Connoisseur
    Automobile(s): 1999 White Diamond ETC
    Join Date
    Jan 2005
    Location
    Dallas, TX
    Posts
    2,531

    Re: The shocks or the air compressor? That is the question.

    Hey zergkiller I have my original dryer apart in case you can't open yours. You'd drop in the new spring and close it back up. The fittings are really easy to use. The trick is to get them together outside, not while under the car so you can see what you're doing and to use teflon tape. All could be done in 1 morning.

    The Monroe ma822 seem like they'd be easier to deal with. Domino1968 installed them on his Dts. But remember you have a leak that has probably already saturated the dryer so good idea to service it either way!

    Btw I also raised my rear ride height to get to like the Gabriels bc they weren't filling up all the way and deflating at declines with the car unloaded. I posted about that. It was a learning and troubleshooting experience all around.

  12. #11
    zergkiller is offline Cadillac Owners Fanatic
    Automobile(s): Cadillac Deville 2001
    Join Date
    Jul 2007
    Location
    Carrollton, Texas
    Age
    70
    Posts
    127

    Smile Re: The shocks or the air compressor? That is the question.

    @mtflight

    Oh! Change the ride height! Now I'm chickening out! LOL. I had it all figured out to buy the things, get them here, and then see about the fittings, find someone with a vice, and then do the job, but it's "change the ride height" is it? Are there any other little thingys I should know about?

  13. #12
    mtflight's Avatar
    mtflight is offline Cadillac Owners Connoisseur
    Automobile(s): 1999 White Diamond ETC
    Join Date
    Jan 2005
    Location
    Dallas, TX
    Posts
    2,531

    Re: The shocks or the air compressor? That is the question.

    Quote Originally Posted by zergkiller View Post
    @mtflight

    Oh! Change the ride height! Now I'm chickening out! LOL. I had it all figured out to buy the things, get them here, and then see about the fittings, find someone with a vice, and then do the job, but it's "change the ride height" is it? Are there any other little thingys I should know about?

    Nah, I only did it because the springs alone held the ride height by themselves, and the replacement shocks weren't filling up all the way. You may not need to do it. Either way it's easy as pie. See here http://www.cadillacforums.com/forums...ar-height.html

    And don't sweat it. I'll help you out if you get in a bind, really. I think it is an easier job than getting those cams in place for the HVAC actuator motor to fit. THAT was a frustrating couple of hours...

  14. #13
    zergkiller is offline Cadillac Owners Fanatic
    Automobile(s): Cadillac Deville 2001
    Join Date
    Jul 2007
    Location
    Carrollton, Texas
    Age
    70
    Posts
    127

    Re: The shocks or the air compressor? That is the question.

    Good lord, what beautiful cars! And a double <WOW> on the write-up. What a great job! I'll really have to be careful.

  15. #14
    zergkiller is offline Cadillac Owners Fanatic
    Automobile(s): Cadillac Deville 2001
    Join Date
    Jul 2007
    Location
    Carrollton, Texas
    Age
    70
    Posts
    127

    Re: The shocks or the air compressor? That is the question.

    I finally got around to updating this thread with the progress on the project. Since the last entry, I've installed the MA822 shocks made by Monroe, and they work perfectly although they are a bit firmer. The female connectors on the ends of the pneumatic lines will pull off if you turn the spring clips 90 degrees. I have removed, and cleaned the pump while I put the new dryer on, and since this was a second operation, this time I reached up into the wheel wells and took the tube ends off the shocks without even removing the wheels.

    I got the dryer from mtflight (the Cool mtflight), and I got to see the mods he has done to his car. The idea of getting upgrades from wrecking yards is pretty darned good. He has a heads-up display for the speedometer that he put in, plus a really neat console and big LCD display for his GPS/CD/TV arrangement.

    Theoretically, you could put in all kinds of goodies if you wanted to.

    But my pump still runs too frequently. It will run every 200 yards in the cold weather I am seeing now.

    The tube set for about $10 is only the ends of the tubes that engage the shocks. Then, you have to buy couplings to couple the new tubes and their shock connectors with the old ones that go into the pump housing. I guess I really don't like that solution. A new GM Part 88952486 harness is $124 here: http://www.gmpartsgiant.com/parts/gm-tube-88952486.html . This one has all of the connectors, including the one to the dryer. I'm saving the money to buy it.

    I called Monroe to confirm what mtflight told me, i.e. that I couldn't just disconnect the relay and shut the pump off with the Monroe shocks. Monroe told me they have to have at least 20psi in them or they will self destruct pretty quickly. The techie guy didn't even like 2 weeks without pressure.

    I didn't like the other suggestion of putting tubes in and a schrader valve to pump them up manually either.

    Other than these things, the only thing I can add to those who have already posted on this subject is that you need to undo the upper mounting bolt for the driver's side exhaust muffler and let it drop to get to the cradle the pump sits in. They both come out at the same time, since the pump sits in the cradle and has its own shock mounts and hold-down bolts.

    Wear some kind of eye protection.

    My thanks to all who have helped thus far.

  16. #15
    mtflight's Avatar
    mtflight is offline Cadillac Owners Connoisseur
    Automobile(s): 1999 White Diamond ETC
    Join Date
    Jan 2005
    Location
    Dallas, TX
    Posts
    2,531

    Re: The shocks or the air compressor? That is the question.

    Hey zerg, thanks for the kind note there. I think you already have a Monroe kit that has the tubing, so you just need the 1/8" pressure-fittings to couple your existing connectors.

    Every 200 yards indeed is too often for your compressor to run. Mine runs from time to time and I do hear it at stop lights, but I figure that's from stop and go and bumps changing ride height.

    Don't spend $124! The compression fittings are around $10 for all 4 you'd need if you want to just replace the tubing.

    Here's a video that illustrates a compression fitting for PVC pipe. It's basically the same concept, and I used 2 such fittings to mate the new tubing from my Gabriel HiJackers to the GM lines at the compressor/dryer. You would use 4, because you'd need to use your existing connectors at each shock absorber.



Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting