rapierau

Need somebody to confirm the following information. For nearly 4 months I have been having trouble with this damn thing and I believe I have finally figured out how to fix it without spending a fortune.

Contrary to what Ford says, you can service the air compressor or at least swap out the failed parts with another compressor you have sourced from the wreckers. Having overhauled the compressor, removed and replaced the feed filter (under battery), removed and replaced fine filter(inside compressor), overhauled piston & checked and cleaned rings), checked the operation of the overpressure switch (air compressor), and resealed the entire unit. I still had severe overheating problems that resulted in system failure.

Yes I have already replaced the air shockers with newbies from Peddars. However, what I didnt count on was the one way flow valve that resides on the inside of the air dryer unit. (This can not be undone - so I destroyed one of these trying to figure out how it worked).

Is this the only one in the system? I am getting somebody to gerry rig a flow value that I can splice into the line near the T-piece. What I need somebody to confirm is, are there dump valves in the shockers that lower the car when it gets to high due to a change in height.

By the way the self diagnostic returns 4 flashes which means correct system operation.

Aussiblue

You haven't used a too small diameter air line (4.7 mm or greater) or pinched the nylon hose somewhere have you? There is only the one minimum pressure retention valve. The vent solonoid on the air compressor manifold controls air exhaustion. The tube vents to the engine compartment via the solonoid. Note the compressor vent solonoid has an internal polorised diode; puting this in the reverse position or switching the battery and earth connections will damage the solonoid.

__________________
Regards Blue

rapierau

No the air hose is original and was cleaned by blasting air from the T-piece back down towards the dryer (when disconnected). The exhaust solenoid as far as I can tell is operational or I would have got a fault signal on the diagnostics. You cant fit the solenoid in reverse postion. It only fits into the compressor the one way and I was careful of this. I also used high temp liquid gasket to reseal both the solenoid and crank cover.

Wiring was replaced and rejoined as per original specs.

I even drove the car with the backpressure solenoid left unconnected (which theoretically means that the system should not loose air at all) and the damn air compressor still overheated due to constant use.

If you are right and the exhaust is controlled via the solenoid and dumps back down the feed line back into the engine compartment, to what purpose (and more importantly) and at what pressure is the flow value in the dryer set. This is definitely a back flow valve. This is the only part of the system I have determined that has failed. ie. the unit within the current dryer is not functioning (air passes from the suspension side back into the air compressor) which did not happen on the other dryer.

Do you think my idea of fitting a gerry rig back flow valve into the system will work.?

Aussiblue

I'm referring to the Ford Factory manual so it should be right. The air enters and is exhausted from the same place; the one inlet exhaust pipe. The minimum pressure valve located in the air dryer maintains pressure in the rear shocks at 60 to 160 kpa. A pressure guage with a T piece in the line near a rear shockie should show 60 - 170 kpa. If the compressor overheats as a result of running too long you either have a leak or the link rod (or wiring) has come loose from the height sensor or the diff. You will see if the link rod is broken or missing but unplug and clean (spray electrical contact cleaner) and reconnect the harness near the diff; loose or dirty connectors here are common.

The manual contains a bold print warning: "Care must be taken when servicing these components [vent solonoid/diode] not to switch the battery feed and ground circuits or component damage will result" so it seems possible they can be mixed up.

The solonoid is the vent solonoid not a back pressure solonoid - disconnected you will lose all air from the system. The pressure retention valve retains the air pressure within range until the vent solonoid is opened.

It does sound like the module near the diff may be badly connected or the module is damaged as this is meant to limit compressor run time and solonoid exhaust time both to a maximum of 2 minutes. It also delays the initiating the compressor relay and vent solonoid for 7-13 seconds so neither the compressor nor solonoid is continually on. Essentially the module monitors ignition and height and switches on the compressor relay or vent solonoid after being told for more than 7 -13 seconds that it needs to raise or lower the vehicle or exhaust all air when the ignition is switched off.

Hope this all helps but let me know if you need more info.

__________________
Regards Blue