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Thread: Eas issues.

  1. #1
    Join Date
    Sep 2016

    Eas issues.

    Hi fellow p38 owners.
    My 96 is still going strong and gets well used for its intended purpose.
    Its over 20 years old and needs attention when things get worn as you would expect, however I do still have problems with the EAS .
    Ive re built the valve block always rebuild the compressor and the reason I rebuild the compressor is that it tends to just cycle continuously.
    The system has no leaks in it ,however the pump get the pressure to 130 PSI .The front then lowers letting air from the air exhaust ? Then the pump cycles again pumps it back up .This process is never ending. Has anyone got any idea what can be done or of any good mechanic that knows about this system in esst Gippsland

  2. #2
    Join Date
    Oct 2007
    Williamstown, Victoria
    I've had this before on my P38, it's called the slow dance, the compressor runs, then shuts off, the eas makes a few exhaust noises, then the compressor kicks in again, with the front continually going up and down. With the compressor running all the time it would cause premature wear to the piston seal.
    Non-return valves leaking will cause the front to slowly dance, (the 3 valves with the springs in the valve block)
    When stopped the front spring valves open to equalize pressure, if the compressor is running AND the non-return valves leak, compressor discharge will go straight into the front springs.
    Once the front height gets enough out of tolerance the ECU will lower the front end, since there's a leak the tank is likely not full so the compressor continues to run, and the cycle continues.
    I had a faulty non return valve, I couldn't find any non return valves as a part, so I ended up getting a second hand valve block and using that for parts.
    Mine has been fine since.
    The tiny o rings can also pinch and cause problems.
    Hope that is of some help!
    Cheers, Pete.
    Attached Images Attached Images

  3. #3
    Join Date
    Nov 2015
    Agree with PeterH, but the dance problem is almost certainly being caused by one or more wheel height sensors sending false or out of range signals to the ECU. So the ECU continually adjusts the other sensors down and if the same fault is triggered in another height sensor the cycle can continue all the way to the bump stops. Air being extracted from an air bag is passed through the dryer (to purge it) and then through the valve block to the atmosphere. I suspect your valve block is an innocent player in this and only doing its job.
    You could also have a hole or tear in one air bag that is only exposed at a certain height.
    If your height sensors are original fit, it would pay to replace all of them. Not cheap, but I've seen their replacement transform a P38. And the new ones will last another 20 years.
    2013 D4
    1966 Army engineering trailer
    1976 SIII diesel tray (farm ute)
    (previously SII 2.25 swb, SIII 2.25 swb & lwb, P38 Vogue, 1993 LSE HS2.8)

  4. #4
    Join Date
    Jul 2014
    Pete is spot on with what happened to mine....I rebuilt the valve block and pinched the o ring which gave me exactly these symptoms, refitted o ring and been good since.
    2000 4.6 HSE Alveston red
    2007 307 xse peugeot
    1974 xj6l jaguar

  5. #5
    Join Date
    Feb 2010
    Townsville, QLD
    G’day mate!

    Can I ask how long you monitor the EAS doing this “fill and release”?

    Usual behavior for about 15 minutes of driving is as you describe. If it’s happening after an hour of driving it might be time to do a suspension height calibration, as it could be continuously adjusting.

    The system is designed to switch the compressor off while lowering any spring, otherwise it will discharge this pressurized air out the exhaust.

    Its really good that you have a strong compressor!


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