P38 THOR V8 Air suspension schematics

[Landroverscott]

If left for a week, my P38’s suspension drops to it stops.

Removed the valve block & compressor to rebuild.

Connected Schrader valves to each of the four airbag lines.

Inflating each airbag, I noticed that the airbag on the opposite side of the axle partially inflated.

Oddly, any discrepancies in the heights I set for each bag levelled out when driven, even though the system is shut down (the relay has been removed under the front passenger seat).

Does anybody have a diagram of the airline system, and does anyone know if there are inline valves or other components between the airbags that could fail?

 

[pwood999]

More likely the opposite airbag lifted a bit with whatever air was left in it. There's no crosslink valves on a P38. All four airlines go directly to the valve block. There's a known issue caused by leaking exhaust that melts the rear lines, but if you can raise the car on the schrader valves then yours are probably ok.

The diagrams are in the EAS System Info document in the Technical Archive section.

Leave it on the valves for a few days, and if it drops either airbags, o-rings or valves are leaking. Soapy water will tell.

 

[Landroverscott]

pwood999, thanks for your rapid repose to me question; much appreciated

I thought as much, having rebuilt numerous vlalve blacks, pumps and replaced loads of airbags on the P38s I've owned through the years. I did soapy water over the colletts and although I saw no bubbles knew it was due for as rebuild.

Interestingly, stood this last five days on valves the back end has dropped on both sides: I suspect leaking airbags on both corners.

Didn't know about the lines melting with exhaust, a good spot and one I'll check. For your interest I created a cheat tool for the airbags, I'll photo it, its a large metal smooth nosed spatula that helps with the last minute life.

So my job now is pump, valve back and fit two new rear airbags: tempted to do the front at the same time as they were all last replaced 10 years ago.

Thanks again

 

[pwood999]

Remember they tend to leak under the folds, so do the soapy water check at various heights.

For the schrader valves, although I don't use them much, I did when rebuilding my engine a while back just raise & lower the car manually. One thing I found it was it was easier by putting a tee into the front pair & same for the rears, so my compressed air raised them both together with equal pressure. Also the valves did leak slightly, but held for longer with the sealing caps on.

 

[Mark Piercy]

pwood999, thanks for your rapid repose to me question; much appreciated

I thought as much, having rebuilt numerous vlalve blacks, pumps and replaced loads of airbags on the P38s I've owned through the years. I did soapy water over the colletts and although I saw no bubbles knew it was due for as rebuild.

Interestingly, stood this last five days on valves the back end has dropped on both sides: I suspect leaking airbags on both corners.

Didn't know about the lines melting with exhaust, a good spot and one I'll check. For your interest I created a cheat tool for the airbags, I'll photo it, its a large metal smooth nosed spatula that helps with the last minute life.

So my job now is pump, valve back and fit two new rear airbags: tempted to do the front at the same time as they were all last replaced 10 years ago.

Thanks again

Now here's a real nice person for you.
Let us know how you get on with the 38'.