It occurs to me that with the one air leak problem isolated at the rear block valve, the reality is that air is still escaping to the exterior.

It may be the the body of the block valve has a crack that lets air out or there is a hole somewhere else between the compressor and rear block valve letting the air escape to the atmosphere. I call this the "middle" area.

If the problem was just leaking orifices, then the air spring air could exit towards the compressor piping but it should not escape with the system depowered and hence there would be no deflation of one of the air springs.

I therefore think once you have replaced the rear block valve, there is still another leak to find, but in the "middle" area. It will not be evident however as the new block valve will be doing its thing - sealing off the two rear air springs and the good front block valve currently does that as well.

Basically the air from the front air spring had to go somewhere when you switched block valves so that suggests a secondary leak. This is typical of anything Land Rover. Rarely is there only one problem - normally there are two or more, and fixing one leads to depression and frustration as there are still additional problems to fix and one may not be anticipating more.

It is possible that the "middle" area leak is the reason you needed a new air compressor - the previous compressor was worked too hard keeping air in the middle; hence you must also find that leak also. The failed rear block valve was a secondary leak and is what unmasked what I think is still another leak. Also now the new block valve will mask the leak again.

Then without the new software, the AMK could cook itself to death due to overwork. Part of the purpose of the new software is to protect the compressor from overheating / overworking. No software, no protection.

 

I will have the software updated properly before I really use the truck.
I am fixing the problems as I'm finding them and yes it is depressing.
how will I be able to find the leak in the "middle"? Especially if the new valve will seal properly.

 

The leak thing in the "middle" will be a matter of soaping most of the fitting joints first around that centre block valve and the new air compressor install.

The new air compressor install will probably be OK as the leak preexisted the install.

You could have a pin hole in the air tank due to rusting out - not uncommon.

If so, that will be more a case of waiting for the air compressor to fill the system up and turn off, then soaping the tank etc. The problem will be that the hole will be at the top or rail side of the tank where you cannot see the bubbles. As such, you will pretty much have to rely on your ears.

If not the tank, then the most obvious place for a leak is the air line between the compressor air out and centre block valve. Note the air line per the first attached jpg between the item marked 12 and the item marked 3.

 

once I get the valve block in I will try and figure out the leak, if there is one. Should the pressure on the gallery go down on its own?

 

I have never quite figured out where the gallery is but I presume that term refers to the location where the air pressure sensor is located, that being 12 shown on that sketch of the air system below. 12 is the pressure sensor and is located on or near what I call the middle block valve located near the air compressor.

When everything is off and stable:

a) air spring pressures should vary between 70 and 140 psig.
b) air compressor internal pressure should be close to 0 psig.
c) air tank pressure should be perhaps 220 psig.
d) gallery pressure should be closer to 200 psig than 0 psig.

If you have a Blackbox or GAP tool, the pressure that it measures is I think what is commonly called Gallery Pressure and that number should be closer to 200 psig than 0 psig. I think the number is the reading taken from the pressure sensor called up as 12.

 

valve in, lets see what happens

 

You are now ahead of the curve - looking for problems now instead of trying to figure out where a problem is - this is a bit more fun - kind of a journey of exploration. Hopefully, have fun this time around.

 

haha! Yes fun! So the valve has eliminated the leak down, it sat overnight with no issue (fuse pulled). Now I need to update the software for the AMK compressor. Where's my IID Tool???

 

I think tonight, you should put the fuse back in and see what Sunday morning brings.

I suspect all four corners will still be good. If not, then probably the auto level system let air out of one or two of the corners - (well there could be leaks in the front block valve, but I think not), hence if one or two corners was down, that would suggest the wheel height sensor on one of the corners is either defective or out of calibration.

When you get the GAP, you will be able to look at the sensor readings and via the GAP website, figure out how to adjust the height readings - it is a bit of a skill and art combined.

Also before you attempt the software upgrade, get as many pressure readings as you can so you can do a before and after comparison.

In particular, we are talking this "gallery" pressure number, as I think there is still a leak to be found. Since I think now both front and rear block valves are properly sealing and probably all four wheel height sensors are OK, hence with the fuse in, there will be no settling.

As I said, if there is, that suggests one of the wheel height sensors, (or I suppose the wiring to a sensor), has a problem.

Given however that the wheel height sensors are good and the auto level does not play games, then gallery pressure will be the story teller. If it remains high overnight, (which I doubt), then there are probably no leaks, if it is near zero, as I suspect, then I think there is a problem in the middle piping somewhere.

Another indication will be the operation of the air compressor, or not, at first morning startup.

In theory, the air tank will be full at engine shutdown the night before and should still be near full in the morning. If not, the air in the tank went somewhere. This is why I think I have at least a minor leak in my system as some mornings at first startup, the compressor comes on for a bit - not too long, so I know the tank is still mostly full, but for long enough that I think it is more than just temperature drop affecting air pressure.

As I said, now the games begin, but on your terms!

 

While you are waiting for your GAP to arrive, you can perhaps watch the video per my Dropbox link below.

The link is to a twenty minute long LR Defender video taken in the deserts of Libya back in 2007. There is a Prado as well.

The best part of it is probably the music so if you have a good sound system attached to your computer, the music is really appropriate in a haunting sort of way.

If you watch closely, you will see a burned out tank; also a burned out Suzuki, (I think).

https://www.dropbox.com/s/00ddxe3375...DV_PS.mpg?dl=0