P38A Quit moving! Eas..a problem found (update)

Mark Piercy · Apr 8, 2020

Pipe in those who can please.
Arrr, bloody thing...
Right then, compressor running at any height other than access.
The front and front only will lift and the compressor will cut out and it will lower to desired height.
Eventually the compressor achieves full tank and the dancing stops!!
I can leave a door open and it'll charge the tank happily. I then shut the door and it sits quite happily and still.
If I raise the body and lower the pressure it all starts again.
So, if there is a leaking nrv does that also mean that the FR, FL, inlet and exhaust solenoids are leaking also.
If there is any solenoid leaking, why does it not drop or change when the compressor is not running or left days on end?
Could it be worn out solenoid piston rubbers that leak under compressor pressure??
Never drops over night or even over a week.

Thanks.

Datatek · Apr 8, 2020

Unlikely to be the solenoid valves if it doesn't drop when left. Have you checked the compressor output?
If the rear does not lift, it s likely there is a leak from an airbag despite it staying up when parked, although if as you say only the front lifts not sure how it can hold the height at the rear.

Mark Piercy · Apr 8, 2020

Datatek said:
Unlikely to be the solenoid valves if it doesn't drop when left. Have you checked the compressor output?
If the rear does not lift, it s likely there is a leak from an airbag despite it staying up when parked, although if as you say only the front lifts not sure how it can hold the height at the rear.

This is the wierd bit, when the compressor isn't running.. It doesn't dance...

Datatek · Apr 8, 2020

Mark Piercy said:
This is the wierd bit, when the compressor isn't running.. It doesn't dance...

What do you mean by "dance" the front doing a little jig when you take your foot off the brake? That could be a sensor full of mud. The compressor may be running to replace lost pressure as it jigs up and down.
Does the back raise or not?

wammers · Apr 8, 2020

Mark Piercy said:
This is the wierd bit, when the compressor isn't running.. It doesn't dance...

The fill chamber exhaust NRV ( NRV 3) is leaking, allowing high pressure air from the fill/exhaust gallery into the corner valve gallery and forcing air past the corner solenoid valves

Mark Piercy · Apr 8, 2020

wammers said:
The fill chamber exhaust NRV ( NRV 3) is leaking, allowing high pressure air from the fill/exhaust gallery into the corner valve gallery and forcing air past the corner solenoid valves

This was my thoughts and it had to be via pressure as it doesn't do it any other time other than filling time.
OK then, I'll strip the block out tomorrow. I'm not too sure and forgive my ignorance, the valves are recent so it could be dirt ingress into the seat or oring or even a worn valve seat 20yrs old
. Which one of the three valves is n°3. Can the valve seat be reprofiled?

Datatek · Apr 8, 2020

Mark Piercy said:
This was my thoughts and it had to be via pressure as it doesn't do it any other time other than filling time.
OK then, I'll strip the block out tomorrow. I'm not too sure and forgive my ignorance, the valves are recent so it could be dirt ingress into the seat or oring or even a worn valve seat 20yrs old
. Which one of the three valves is n°3. Can the valve seat be reprofiled?

I doubt it's the valve seat. It could be desiccant from the dryer clogging things up.

Mark Piercy · Apr 8, 2020

Datatek said:
What do you mean by "dance" the front doing a little jig when you take your foot off the brake? That could be a sensor full of mud. The compressor may be running to replace lost pressure as it jigs up and down.
Does the back raise or not?

Dancing, it'll move upwards à touch and then drop down to its height.
Even when left ticking over and unloaded. The back never moves unless asked to do so. But never when the compressor has stopped.

Mark Piercy · Apr 8, 2020

Datatek said:
I doubt it's the valve seat. It could be desiccant from the dryer clogging things up.

Very possible although it has all been changed and all the orings and so on renewed. But then early failure in any area is a possibility.

Datatek · Apr 8, 2020

Mark Piercy said:
Very possible although it has all been changed and all the orings and so on renewed. But then early failure in any area is a possibility.

I have had a not very old dryer let go, it filled the valve block with the white powder and disabled the suspension.
Luckily I was able to level it and lock it at just above access with diagnostics and drive home.

kermit_rr · Apr 8, 2020

Mark Piercy said:
Dancing, it'll move upwards à touch and then drop down to its height.
Even when left ticking over and unloaded. The back never moves unless asked to do so. But never when the compressor has stopped.

that sounds similar to what mine does.. a few clicks up at the front, then a few clicks down to the original level, like its trying to find an unachievable value from the height sensor

Mark Piercy · Apr 8, 2020

kermit_rr said:
that sounds similar to what mine does.. a few clicks up at the front, then a few clicks down to the original level, like its trying to find an unachievable value from the height sensor

Thats what I originally thought, but then it stops when not charging the tank with air. A strip out tomorrow will reveal all hopefully....

Datatek · Apr 8, 2020

kermit_rr said:
that sounds similar to what mine does.. a few clicks up at the front, then a few clicks down to the original level, like its trying to find an unachievable value from the height sensor

Readings too far apart across the axle.

Mark Piercy · Apr 8, 2020

Datatek said:
Readings too far apart across the axle.

With in 2-3 bits digits... Thingys...

kermit_rr · Apr 8, 2020

Mark Piercy said:
Thats what I originally thought, but then it stops when not charging the tank with air. A strip out tomorrow will reveal all hopefully....

mine stops once the pump starts running, then starts again once the pump stops

Mark Piercy · Apr 8, 2020

kermit_rr said:
mine stops once the pump starts running, then starts again once the pump stops

Maybe a learning curve for us both then?

dubbleRR · Apr 8, 2020

Mine used to do the two clicks up n two clicks down .But when i was changing the radius arm bushes ,I noticed that the eas sensor elbows were dry ,stiff,... even the connection on to the radius was dry. so a bit of grease ,After that my dancing stopped... .....RR

Mark Piercy · Apr 9, 2020

dubbleRR said:
Mine used to do the two clicks up n two clicks down .But when i was changing the radius arm bushes ,I noticed that the eas sensor elbows were dry ,stiff,... even the connection on to the radius was dry. so a bit of grease ,After that my dancing stopped... .....RR

Been there, checked that, that was something I had considered also.

Mark Piercy · Apr 9, 2020

Well, that was a waste of time.
The valves were cleaned and inspected along with their corresponding seats... Made no difference.
My next step is to check the inlet solenoid because air is allowed to the valve and only through when the solenoid opens.... Anyone?

Mark Piercy · Apr 9, 2020

wammers said:
The fill chamber exhaust NRV ( NRV 3) is leaking, allowing high pressure air from the fill/exhaust gallery into the corner valve gallery and forcing air past the corner solenoid valves

Is there any chance that the inlet solenoid could be allowing air also?
From the diagram I have, if being it correct... The air would leak past nrv3 and also pass through the exhaust valve as well?

P38A Quit moving! Eas..a problem found (update)

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