Below is a link to a number of files related to thread and adapters into the air tank. I installed a Schrader valve sometime back for the purpose of pressure etc.

I think you will find an engine compression tester gauge as suitable.

DISCO3.CO.UK Photo Gallery - Schrader Valve Air Tank Air In install

 

The link below is to the AMK compressor site.

The link does not have much that I can find on the air dryer other than the boast that the dryer is "integrated" and has a quick release function. None of that is very helpful as it all infers the air dryer lasts forever, hence why the need for the quick release.

I assume the air dryer is "integrated' within the black bits on the top but I do not know for certain.

Compressors for air suspension systems | AMK

This is a 10 page thread re install of the new compressor.
DISCO3.CO.UK - View topic - How To - AMK Suspension Compressor Replacement

 

So I have to say Bbyer you are an extraordinary wealth of information when it comes to LR3s. Also your suggestion to use an engine compression tester worked perfectly. I had a Diesel Injector adapter that was the same M20x1.5 thread pitch as the plug on the tank.

Now on to the results...

Tank pressure at compressor cut-out- 254 PSI
Pressure drop per increased ride height change- 45 PSI
Minimum Pressure required to physically lift vehicle- 120 PSI

I do not know if my LR3 has the newest updates, however I do have the new style AMK compressor with a manufacture date of January 2014, so presumably it was installed within the last year and a software update is a requisite for installation

 

I almost think that when your AMK was physically installed, no AMK software update was done.

Prior to about 2008, I would say your pressure numbers look great and that would be true of the Hitachi, pre "Hitachi", software update.

There were actually two software updates - one related to the Hitachi compressor but obscured by LR as a product improvement. LR never says they are sorry or admits to ever being less than perfect, instead the code term is "product improvement" and as such, is most often billed.

Back in 2006, they did a number of free software updates on the pervious production vehicles as there were "concerns". Then about 2008, to address the large number of failing Hitachi's still under warranty - (that is when failures are a true concern), one of the product updates included reducing the design shutdown pressure from about 244 psig to something closer to 210 psig. I say "something" as LR never admits to anything.

Most vehicles got the update but of course not all as the software tended only to be loaded when a replacement compressor was installed.

Then due to the floods/earthquake in Japan, in 2011 the Hitachi compressors became unavailable and that forced Land Rover to switch to the AMK units in both the new production 4s and as a parts replacement for the 3s. Along with the new AMK in the 3 came the software update that changed pressures and instructed the air system computers that the AMK operated a bit different than the Hitachi.

The reality was that for the most part, there did not appear to be any difference in the operation of the AMK vs the Hitachi, hence the belief grew that the software update was only an additional dealer billing opportunity.

Also since the software update billing was independent of the install, many owners declined to pay for the update, hence it would not be installed.

The dealers did not fight the owner as the techs generally hate doing any software updates as they go not get paid enough plus they never know if the outcome will be satisfactory. Land Rover also wins as when the AMK fails, they will claim no warranty as the update was declined.

Well that is my version of the story anyway but I think your AMK has yet to see the AMK update or even the old Hitachi update.

Incidentally, with the lower pressures, the 3 tends to be slower to rise in the front than the rear and hence there is again a bit of the camel effect present in the older FFRRs. I expect your 3 raises quickly and evenly both front and rear. With lower pressures due to the update, that will probably not be so.

 

Only the LR4 gets the lower (189psi) pressure software update due to slightly different suspension geometry. LR3s are still 258psi Max. The software "improvement" was to activate the compressor supply line pressure dump gate at the completion of each compressor run. There is a valve that keeps the tank pressurized. This makes it easier for the compressor to start the next time.

 

Yes, I have seen that chart previously and it has also got me to wondering if there are a number of different software loads around.

The 258 psig number was what first intrigued me. The early, (2005) Land Rover pdf's always used a 244 psig number, hence the 258 was news to me. It however just be differences related to maximum and nominal numbers. All that means however is I do not know everything - not a real revelation.

Page 75 or 9/22 of the link below is typical of the original LR material so the question is always what have been the changes over time as I have always regarded it as tough to see any numbers on LR issued paper.

http://www.disco3.co.uk/gallery/albu...escription.pdf

The second pressure on the chart that really surprised me was the 189 psig number re the D4 that refers to the AMK compressor. I wondered if the air tank size had been increased or if the camel effect was even more pronounced than I might have been aware of. I see the term "suspension geometry" so I suppose that can cover, (or hide), a lot of changes.

As usual, a Land Rover is always a bit of a mystery.

 

The interesting thing I saw, was that 120 PSI is the lowest pressure needed before the vehicle will actually start lifting. Below that, any raise in height selections the LR3 would not move until tank pressure reached 120 then very slowly the LR3 would rise. Tank pressure would not increase past 120 until the ride height was achieved then pressure would resume building. So the system is more than capable of operating with 189 PSI

 

This is getting interesting.

It is starting to sound like LR got realistic and recognized reality.

Most compressor people accept that it is simply not possible to build a single stage compressor that can do in excess of 200 psi for any length of time.

All highway tractor trailer units, busses etc, that have air suspension or air brakes run on nominal 150 psi systems - and have year after year in a very reliable manner.

The bladders are therefore designed for a nominal 150 psi as are the compressors and air storage tanks and that is why you see the lower numbers in our 3 when it comes to airspring pressure. (Land Rover could not completely reinvent the wheel.)

The airsprings in our 3 are just smaller versions of the ones in the big trucks. The pressure in these springs runs between 90 and 140 psi as mentioned in the post above.

What LR did however, was realize that not in common with big trucks, LR did not have the room for a single big air tank under the vehicle that would allow all four airsprings to routinely lift the 3 from access height to normal without the camel effect happening as was the case with the earlier FFRR, I think they call them the P38s?

Range Rover (P38A) - Wikipedia, the free encyclopedia

Rather than install a second air tank on the right rail, LR instead chose to purchase a single stage compressor that was purported to be designed to far exceed the 150 psi limits of commonly available units - that was our Hitachi compressor and it does work fairly well for at least a couple of years.

A problem of course for LR arises when the first owner warranty is four years and the all maintenance included leases tend to that time frame as well. At the same time, one must conclude that it was not that big a problem as LR did not do much other than generate software revisions until they could no longer obtain the Hitachi unit.

With the 189 psi numbers of the AMK unit, it would appear that Land Rover in their wisdom, has finally recognized reality and specked a strong 150 psi unit. I think in this lower pressure environment, the Hitachi would then also be a fine reliable unit as well.

 

Bbyer, do you know for sure that your Lr3 is a lower pressure than 250? Have you used a pressure gauge on your system?

 

Yes, I put a pressure gauge, (compression tester gauge), on the Schrader valve that I installed in the end of my air tank - maybe five years ago now and the reading was about 210 psig.

At the time, I thought it should be higher so was a bit disappointed.

Also last week and just now since I am doing this post, I just checked what is called "gallery pressure" using my Nanocom Evolution II and the pressure showed as 213 psi today and about that a few days back when I was clearing codes on another matter.

I just think there are many differing software loads out there and LR continues to experiment. I still have the Hitachi compressor; it was dealer installed new back in June of 2010 at about 103,000 km (64,000 miles) and probably had the software "fix" current at that time.

This is the link to the Schrader valve in the air tank album.

DISCO3.CO.UK Photo Gallery - Schrader Valve Air Tank Air In install