300bhp/ton · Apr 18, 2024

Is there a guide to swapping out (removing/refitting) the valve block on a p38? As my 4.6 is on coils and the 4.0 I bought recently still has this front sinking issues on the EAS. I wanted to swap the valve block over from the 4.6 to see if it fixes the 4.0

Thanks.

pwood999 · Apr 18, 2024

Unplug electrics. undo the small screws holding the cruise pump in place. Pull out airlines if there are any left. Then there's four 13mm bolts holding the housing in place.

Alternatively if you want the cruise pump working again, simply undo the three 8mm bolts holding the valve block in the plastic housing.

Datatek · Apr 18, 2024

300bhp/ton said:
Is there a guide to swapping out (removing/refitting) the valve block on a p38? As my 4.6 is on coils and the 4.0 I bought recently still has this front sinking issues on the EAS. I wanted to swap the valve block over from the 4.6 to see if it fixes the 4.0

Thanks.

As above but you will need to undo the blue pipe from the compressor, remove the driver pack and de-pin the connections for the pressure switch by first removing the yellow insert in the connector you can then push the pin latch back. Polarity is not important when putting the pins back.
Having said all that, sinking suspension is more likely to be leaking air springs than the valve block.
Actually, the best place to start would be to get it up to normal height and then remove the EAS relay under the passenger seat. That will show if it's just one corner leaking.

300bhp/ton · Apr 18, 2024

Thanks. New front airsprings already. If you start it up and let it run with a door open for a bit and then shut the door it'll shoot up to ride height, leave it running and it'll sink at the front. If you start it from entry height and don't leave a door open it won't ever reach ride height. So I'm guessing a leak in the valve block most likely now.

When you turn the vehicle off it'll normally (and quite violently) expel air out via some clicks from around the valve block and drop the vehicle pretty quickly once the engine is off.

Datatek · Apr 18, 2024

300bhp/ton said:
Thanks. New front airsprings already. If you start it up and let it run with a door open for a bit and then shut the door it'll shoot up to ride height, leave it running and it'll sink at the front. If you start it from entry height and don't leave a door open it won't ever reach ride height. So I'm guessing a leak in the valve block most likely now.

When you turn the vehicle off it'll normally (and quite violently) expel air out via some clicks from around the valve block and drop the vehicle pretty quickly once the engine is off.

To have one corner valve leaking is of course a possibility but I think to have 2 leaking is a bit unusual.
Clicks from the valve block means it's doing something like trying to keep it level. It really needs diagnostics to see what is going on. No leaks where the pipes go into the air bags I suppose? There have been a few cases where bags have been supplied with only on O ring in the pipe entry.

Rubberknees · Apr 18, 2024

Datatek said:
To have one corner valve leaking is of course a possibility but I think to have 2 leaking is a bit unusual.
Clicks from the valve block means it's doing something like trying to keep it level. It really needs diagnostics to see what is going on. No leaks where the pipes go into the air bags I suppose? There have been a few cases where bags have been supplied with only on O ring in the pipe entry.

+1 one that. Had on my front right when it was replaced

300bhp/ton

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pwood999

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Datatek

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300bhp/ton

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Datatek

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Rubberknees

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