99 Seville STS rear air ride low ?

SevillianSTS · #1 (**permalink**) 11-03-09, 04:01 PM

My buddies STS seems to sit a little higher than mine in the rear.
Then when you put stuff in the trunk to go on a road trip, my car seems to sit noticeably low.

Unloaded: when you start the car the compressor cycles once and stops. Sits just a little low.

Loaded with cargo: The compressor runs, stops and then usually runs again, and possible more... but by then I am usually driving. Sits Noticeably lower than normal.

At my last oil change my dealer said my air lines all look ok.

Should I replace the lines first, or is it pretty common for the compressor to be bad. I guess it could also be the rear struts.

Any advice ?

Thanks in advance.

Ian-STS99 · #2 (**permalink**) 11-03-09, 04:17 PM

Check the rear struts for leaks. Also check the DTC for codes, if you have a RSS code of C1738 the compressor is telling you there is a fault with it and it needs looking at.

SevillianSTS · #3 (**permalink**) 11-03-09, 04:44 PM

Do I need to do a soapy water test, or should I be able to hear it if I take the wheel off, on the struts?

stsgus · #4 (**permalink**) 11-03-09, 06:22 PM

Check the air hose coming out of the compressor. I just replaced my compressor, when I took out the old one, the hose was so terribly dry rotted its no wonder why my compressor failed.
I have 98sts. Its alot of fun r/r the air ride compressor. Just hope its that and not the control module, that thing is $1200 ish just for the part......

I dont think they could of used a crappier air hose......

strutmaster · #5 (**permalink**) 11-04-09, 01:38 PM

It could be a number of things going wrong with that suspension...if the compressor's going bad, it got overworked and is getting burnt out from leaky struts. You can start replacing parts to try and fix it, but you'll end up spending a lot more money than you want to. I would suggest doing a conversion to a coil spring and get rid of the air in the rear all together. Probably save you some headache!! Check out Strutmasters; they have good prices (a lot less than the dealer!) and the kits have a lifetime warranty...either way, good luck! Let me know how it works out for you!

Ian-STS99 · #6 (**permalink**) 11-04-09, 03:18 PM

Hmmm @ the above posting !!!

Monroe also does replacement struts / shocks, these being passive and active, the active set is half the price if the OEM parts from GM/Cadillac.

submariner409 · #7 (**permalink**) 11-04-09, 03:31 PM

His car does not have Ford's air bag suspension. It is a normal coil spring/suspension arm setup with drag link which uses air bagged rear shock absorbers to control rear level as in: rear seat passengers and trunk loads. There are no rear McPherson struts as are used in the front suspension.

The system uses a small air compressor with a dryer/filter intake/exhaust setup so it responds to various loads and is controlled by a height sensor and connector arm in the RR wheelwell.

If you remove, modify, replace or defeat the system you then revert to a standard shock absorber setup which will not level the rear of the car in response to loading. Not that it's all bad; you just lose level control. It is entirely possible to install a manual set of Air Lift bags and control rear height manually. Air lift has been around for a very long time.

SevillianSTS · #8 (**permalink**) 11-05-09, 12:39 PM

Thanks for all the input guys... I am planning on keeping the compressor setup.
Car is still driveable, just can't load up the trunk too much.
Think I am going to check the lines over real well, and them eventually replace the compressor. I'm sure I could probably even sell the old one on ebay to get a little back.

My last question though is, how likely is it that the struts are leaking? rather than it be a bad compressor.
And yes, I know it could possibly be a little of everything.

submariner409 · #9 (**permalink**) 11-05-09, 03:44 PM

The rear shock absorbers have integral air bladders - that's what performs the level control - and they dry out and get cracks over time. Entirely possible they're leaking.......any type of shock or air bag, even coil springs, eventually gives up. Imagine the beating they take while controlling a 4,000# car and it's a wonder they last as long as they do.