Hey guys I'm new to this forum and to Fords air leveling suspension...I hope someone can help me out here. I just bought a 1997 Ford F250 non-Super Duty, I see that both air bags are fully inflated all the time and it rides like a brick. I have never dealt with these before, what should I look for first? The truck sits up too high in the back right now...is there a common probelm that these encounter? The truck has 140k miles on it, otherwise in great condition...Any suggestions would be greatly appreciated.

 

To my knowledge there was never an air suspension system on the OBS f250. look for the air lines and follow them to the the valve and you should be able to deflate them a little. Firestone and air-ride make these units for the rear of trucks.

 

I know this is a factory set-up, theres a light on the dash that says "Check Suspension"...I've looked into it a bit more and there are 2 electric "sensors" (1 on each side from leaf spring to frame) that must tell it to inflate or deflate. Theres also, from what I've read, a little control unit somewhere on the truck that must process the feedback and run the compressor accordingly. If anyone knows how to start troubleshooting this I'd love to hear some ideas.

 

This would not be the 97 OBS, it would be the 97 new body style light duty truck and they did have an option of this including the two sensors on the rear springs as described. I just looked at all data and it looks like you can turn off the system with a switch by the right hand kick panel.

Turn the air suspension switch to the off position. WARNING: BEFORE REPAIRING ANY AIR SUSPENSION COMPONENTS, DISCONNECT POWER TO THE SYSTEM BY TURNING OFF THE AIR SUSPENSION SWITCH LOCATED IN THE RH KICK PANEL AREA TO PREVENT VEHICLE DAMAGE OR PERSONAL INJURY.

 

More info:

The air suspension height sensors are connected between the frame and the anti-wind bars. The air suspension height sensors send signals to the control module via magnets mounted in the lower slide portion of the air suspension height sensor. Movement generates a signal through two small Hall effect switches attached to the air suspension height sensor housing. There are four possible conditions that the control module interprets from the signals:


Vehicle is at trim height.
Vehicle is below trim height.
Vehicle is above trim height.
Incorrect height information.
When the height sensors are compressed, the rear of the vehicle is being lowered and this will cause the air compressor to turn on and pump compressed air to the air springs. When the sensor is extended, the rear of the vehicle is being raised and this will cause the air to be vented from the air springs to lower the vehicle back to its trim height level.

 

Allright, its starting to make sense...For some reason mines not getting the signal to dump air from the air bags. I'll look into it tomorrow, maybe I'll take the sensors off and actuate them manually and see what happens. Thanks for the info, I appreciate it. If anyone has worked on or repaired one of these systems I'm open to ideas...from what I can find the sensors are not cheap...Hopefully mine are alright.

 

I am having the same problem, except my rear end is sagging. It rides really stiff. Could you or somebody help me? Thank you

 

I think I just blew an airbag, a mechanic replaced one of my 97 3/4 ton light duty OEM bags but now I think the other one went after towing my camp trailer this weekend, thinking of doing it myself, any advice besides shutting off switch under dash?

 

Moved to the correct forum.

 

looks like some of the dealers get confused looking them up and a 4x4 place said mine was the first factory Ford airbags he has ever seen.. well for my 97 F250 LD truck, the ford part # seems to be F75Z5A891CA if that helps any others out, I got one coming NIB from ebay for 369 shipped! Better than the 671 full dealer price, will report how replacement goes

 

The bag solenoids have to both open and let air back to the vent function on the head of the compressor.
When the Trim sensor goes high it signals the contol module to do these functions.
It's hard to tell where the failure is without testing and service info.
There would be a service code stored as a BXXXX code.
There is also a full system test of all functions.
The system is complex as there are many functions that are available.
I have the service disc but it to much to handle on a board.
Most dealers and shops are not well informed on air suspension so you can have a difficult time even with dealer service because they don't see many over the years.
My experience goes back to the late 80s and early 90s with Lincoln four wheel air suspension systems and their now primitive control sytem by compairison.
They all work very closely the same but with different hardware over the years.
Not much help but to let you know a little about the way they work.

Best I can offer to get the truck down is to apply grounds to the bag solenoids to open them up 'same as the controller would do' then hope there is enough leakage in the line connections back to the compressor head to let some air out.
The bag solenoids normnally have 12 volts on them at all times waiting for control function grounds from the controller.
I would turn the suspension switch off and leave it that way until you decide to work on it.
It will light the lamp when turned off but yours is already on so there won't likely be a change.
Hopefully it's just a case of the controller getting a bit confused if someone jacked up the frame and let the axle hang. That's a no no without the suspension switch being turned off. Same for towing etc.
Good luck..

 

Great info Bluegrass, thanks !

 

So this is the old bag, found the tear after I pulled it farther apart. A very strange foreskin type set up, hard to believe folding rubber can take that kind of abuse



and what the new one looks like out of the box



seemed to pump up and level fine again, im back in business !

 

Well to get deeper and more technical about the bags, here are some thoughts.
The bag rubber is made flexable by certain chemicals in the mfgering process.
As time and elements roll by these chemicals migrate out of the rubber compound making the rubber begin to get hard.
At the point the bag rolls under on it's hard form, the rubber begins to split in very small slivers from the outside inward.
Pin holes begin to take over as the hardness gets to the inside and cause leaking to begin.
It can get to a point that the leak area is sealed depending on where in the rollover it is and what position or pressue brings it to that point.
Bottom line is the leak can seem intemittant due to suspension movement and load.
When it begins to get bad enough it runs the compressor too often wearing it out prematurely as well as saturating the dryer with outside moisture from excess operation.
When this happens especially in freezing weather the dryer moisture freezes, water is passed to the bags and the solenoids and lines can freeze inoperative until the temperature goes up.
I know many did not expect to hear these things but they are a real part of an air suspension's life aging process, if one cares.
Good luck.

 

Hmm now when she sits for a little while the truck seems to sit a little lower in the rear than before, would this be a sensor adjustment ? I will see if it comes up after she starts, the compressor use to kick on even when she was sitting without keys in, but havent heard it kick on while parked yet. Will have to monitor the situation, i hope the other one is not leaking now

Oh is there a fuse that may have blown when the truck is off that kicks the compressor on?