ANOTHER thread about front air suspension drama...

izackary

izackary

Nomad
OK, here is why I'm starting a new thread. I try to be good about searching, but I couldn't find a close enough topic to my scenario, so here goes:

Today I put a deposit down on a '96 LSC which obviously needs some front suspension work. I say obviously because the front tends to drop rather quickly. And by quickly, I mean the front lip below the bumper cover is nearly kissing the ground while the back looks normal. In fact, the driver side looked to be slightly higher, maybe by a half inch, but then it was parked a bit off-kilter, too. Keying the ignition on causes the compressor to kick on and lift the car back up to normal height. However, 20 minutes later the car has obviously dropped some; I will cycle the ignition and listen to the compressor run another 20 seconds or so. I haven't yet got the car home so I can inspect it closer, but do leaky airbags fart out air THAT fast? All I have read is if the compressor is lifting the car up like it should be, it will sit overnight and drop maybe 2 inches. Maybe that is just on newly cracked bags? I am hoping it will just be O-rings or something stupid, but am prepared for it to need 2 new front assemblies. Monday I should have the car at the house, at which point I will go at it with the soapy water and such.

Preliminary thoughts, anyone?
 
LSC HUNTER

LSC HUNTER

New member
Mine started with the drop over night sometimes and then over the next two seasons, and why I parked for winter early I would shut the car off and get out to hear the air leaking from the fromt left bag. If I grabbed the fender and pulled up a bit it would roll the bag enough to seal it up and not let it fall on its face in 10 seconds.

New bags required.
 
Mad1stGen

Mad1stGen

Booster
Anybody hoping that 16 yr old airbags do not leak is crazy ;)

Either the rubber bladder or the top mount is letting the air out.
O-rings might let some air thru, but only if the solenoids were removed recently.
Actual lines have nothing to do with this.

I'll buy a beer at Carlisle if it's something else ;)
 
SCTBIRD1173

SCTBIRD1173

Mark my Bird!
I'll have to +1 to LSC Hunter's post. My suspension is all original 102K and my LF bag leaks BAD. When I was getting it ready for Carlisle I saw all the dry rotting at the fold in the bag and found the leak. Sometimes I shut the car off and I can hear the bag hissing right away, other times it'll stay up for a couple days. I'm replacing the entire system with all new Ford stuff since I'm only doing it once. The car will never see anything like it did the first 100K of it's life.
 
izackary

izackary

Nomad
So I picked up the car today. Interesting detail: I parked at work at 1 this afternoon, and switched off the air ride in the trunk to see if there would be any difference. Lo and behold, I get back to the car just past 4pm and the front is STILL standing. I drive about 6-7 miles (some highway), and the front is down a little bit, maybe from highway venting? (I forget if it still vents with the switch off...) In any case it is a good step forward from where I was at this morning. Especially seeing the car was marked down from $2995 to $2300 as-is! :)
 
budpytko

budpytko

Super Senior Associate
It proves to me that the leak IS in the bag after it shrinks to park height..... the leak is in the folds of the bag.... where they all are.
 
izackary

izackary

Nomad
Hang on, so the suspension leaks like a sieve just parked, ignition off with air ride on...but with the switch off it holds air just fine, but you say it's the bags? It doesn't make sense to me that the leaks will be where the folds are, not if it drops from parked height to the ground with the switch on. Wouldn't the folds be straightened out in that case, too?
 
B

billcu

Head Moderator
It depends when you turn the switch off.

If you turn it off before it vents to parked height (leave door open when you turn the car off, then turn switch off) you have a better chance of them not leaking too much overnight.

Have fun playing "it only leaks when..." . :D
 
izackary

izackary

Nomad
I may have gotten a little closer today...I found out if I shut the car off, open the door, allow the vent to start, then flip the switch, it keeps venting. And venting. Etc. However, I started it back up, turned the switch on to pump it back up, then flipped it off with the car running, THEN turned off the ignition, it stayed up so far. I'll see later when I get back to the car if it is still up. But overnight, it only dropped a half inch on either side, attributable, I am sure, to the drop in temp.
 
izackary

izackary

Nomad
So when the air ride switch is left on, the compressor is allowed to vent, which may exposed folded cracks, while the vent solenoid sticks open? Doesn't it shut once the compressor begins pumping? So it might stick closed but not stick so much that it can't be forced shut by flow of pumped air or something...? (Don't mind me while I think it through out loud...) ;)
 
driller

driller

El Presidente
izackary said:
Doesn't it shut once the compressor begins pumping? So it might stick closed but not stick so much that it can't be forced shut by flow of pumped air or something...? (Don't mind me while I think it through out loud...) ;)
Click to expand...
If it sticks, it will stick partially open or it will stick shut.

If it sticks shut, the suspension will not vent.

Pretty easy deduction from there.
 
izackary

izackary

Nomad
OK, I think I'm catching on. I never had to investigate the system this thoroughly before. My old car's air ride broke 3 times, all obvious faults. Front height sensors, plus the compressor quit on me. I suppose the next step would be to see when AAS has their compressors back in stock....

If I am understanding this better, (thanks for everyone's patience with me, by the way!) what is likely happening is that turning off the car with the air ride on like normal causes the compressor vent solenoid to open so it can vent to parking height, however mine is sticking open, so once parking height is reached, the car continues to vent? But with the switch turned off before the ignition, it is disabling the ability to open said solenoid once the ignition is turned off afterwards?

But why then, do the rear bags not drop to the ground? Are they on a different channel in the lines or something? Or like I proposed before, the front vents enough to expose cracked folds in the front bags?
 
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B

billcu

Head Moderator
izackary said:
I may have gotten a little closer today...I found out if I shut the car off, open the door, allow the vent to start, then flip the switch, it keeps venting.
Click to expand...
Opening the door shouldn't allow the vent to start, closing it does.:)

I'd drive it with the switch off for a while to check for leaks now.
 
izackary

izackary

Nomad
billcu said:
Opening the door shouldn't allow the vent to start, closing it does.:)

I'd drive it with the switch off for a while to check for leaks now.
Click to expand...
I thought I had yesterday with my highway jaunt, but I will try again. (Yesterday the car was quite low when I parked after that drive.)
 
izackary

izackary

Nomad
So apparently the air ride is behaving itself today, probably only to spite me since I have the splash shield off (partially) inside the passenger wheel well to try and listen for the leak. All day, the suspension has not leaked, but while I've been waiting, I took a couple pics.

This is the passenger side bag while the car is parked at full height (from what I can tell).



Despite the light cracking there, NO air has been leaking, still. Here is the yucky-looking compressor assembly: :(



The sound deadening fabric there is very damp. I'm sure it could be wrung out like a dish sponge. In fact the same padding at the very front of the splash shield is also quite damp, but keep in mind it rained all day yesterday. In any case, I don't like that so much moisture is right there at the compressor; obviously it has seen better days!
 
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