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Discussion Starter · #1 ·
I purchased a used 2007 LR3 SE with 80k miles in January.

So far i've replaced the battery, front lower control arms, and coolant bleeder fitting.

Lately i've been getting suspension faults, orange light normal suspension height only.

When I would crank the truck the compressor would run for about a minute then a fault would throw and compressor cut off.

Its sat for over a week at a time with no leaks.

I did a lot of research and found that there is a rebuild kit available for the compressor but I had a lot of trouble finding anyone whom had actually done the rebuild.

I found several threads about removing and replacing the compressor but nothing about actually repairing it.

Today I took this on and documented the steps. Its super easy, the hardest part is actually removing the compressor. Rebuilding takes maybe 10 mins.

I'm not going to go into detail on removing the compressor but once its on the table here are the steps to rebuild it.

Heres the rebuild kit...I purchased it off of ebay for like $35

It contains a new exhaust valve plunger and spring, along with an assortment of o rings and screws.

After getting the compressor on the table it appears that it may have been replaced before. I found numbers written on the end with a paint marker like junk yards do to pull off parts. Not sure if thats factory or not?

Heres a couple side shots of the compressor on the table

Heres an inside shot of the compressor housing...It's easy to see how the compressor over heats being surrounded by this huge insulated box. I chose to leave it off indefinitely...I don't mind the extra noise and plan on adding some rock sliders to protect it anyway.

To replace the exhaust valve you have to carefully remove a 17mm bolt on the side of the compressor. Be careful not to let the spring fly out.

Inside you will find a small spring with the rubber valve on the bottom surrounded by the spring.

During this process, I found no real damage to the original parts. The springs may have become spongy, but the only damage i could find is the o-ring surrounding the bolt i removed previously to access the exhaust valve and spring.

Inside you can see the exhaust port. Simply drop in the new plug and spring. Be sure that it is centered over the port. Replace the o-ring on the bolt and slowly tighten down ensuring the spring doesn't bind or become off center.

Next up are the compression springs. They are located under the black square cap with four screws located at each corner. Slowly loosen each screw but don't completely take them out. This cover is compressing two springs which are pretty stout. It can easily shoot out if not careful.

Once removed you can see the two springs along with the old o-rings

Remove the larger outer spring to gain access to the inner spring and teflon collar.

Heres a side shot of the two springs

Inside shot

Insert the new inner spring and collar then place the larger spring over the smaller. Replace the large o-ring and put the cover back on. Compress the springs under the cover with your hand and start the screws on each corner. Slowly tighten each corner a little at a time to ensure the springs and o-ring seat correctly.

And thats it for the kit. Super easy and relatively cheap.

Now for the part that I believe was causing my issues.

The desiccant air drier. Its the large black canister with the hose coming out of the end. I live in Mississippi and the previous owner did as well. It gets very humid down here. My suspicions were that the desiccant media inside the drier had become saturated and was restricting air flow to the compressor causing it to work harder and eventually overheat and throw errors.

You can simply replace the canister with a new one. But they are expensive and the original is simple enough to repair for free.

Removal is simple. Remove one phillips screw and carefully twist and the canister will slide off the intake. Once removed you need to remove the six screws from the end using a torx 30 I believe. There is another spring under this housing so be sure to back the screws out carefully.

Once you pull the spring there is a plate that applies pressure to the desiccant media underneath. Remove the plate to gain access to the media.

Its a good idea to wear rubber gloves when handling this stuff. It is damaging to skin and is toxic if ingested.

After dumping out the media it's easy to see my problem. The media is totally saturated and had began to crystalize. On the bottom there was actually moisture inside and the media had became hard and stuck to the exhaust port totally blocking air flow.

Here are the two plates along with the paper filters.

Now here's the trick. You can heat the desiccant in an oven to renew it. It draws out the moisture and it turns the chalky white back to a bluish tint.

I placed the media into a disposable cooking pan and placed it in the oven for 30 minutes at 350 degrees

After some time in the oven the media becomes blue once all the moisture is gone

Once it has cooled for a few minutes dump it back into the cleaned canister and reassemble.

Once you replace the cannister your done. Simply bolt everything back up and plug in the harness and air lines.

I cranked my truck and after a minute or two the compressor cut off on its own with no more fault...success!!!

I've driven a couple of days now and there has been a noticeable difference. Without the cover on there is an increase in noise but not annoyingly so.

I've noticed that the compressor doesn't run near as often as it used to. Also, my truck lifts much faster to off-road height.

Overall I am very happy with my $35 fix.

This isn't a cure all, obviously if the compressor has gone neglected long enough internal parts that cannot be replaced may have become damaged. I don't necessarily think it needed the rebuild kit as most of my issue was with the air drier. But it's cheap and easy to do and it gives me some piece of mind since I was repairing the drier anyway.

I'm going to get in the habit of replacing or rejuvenating my air drier every 50k miles or so. I believe this would help tremendously in the longevity of the compressor itself.

Anyway, I'm no expert or land rover mechanic but hopefully this will help someone in the same situation as me.

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Nice write up. I'm not convinced the desiccant is worth renewing, but replacing the air drying might be the way to go.

In any event, great pictures.

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Very impressed.

The air dryer is the real trouble maker so what you did was impressive.

I am much more lazy in that one can purchase from the UK or Germany, filter/ desiccant kits. In some cases, the beads have turned to dust, hence the need for new desiccant material.

I probably would have installed the plastic surround covers as they keep not only the compressor sort of clean, but also the nearly block valves and lines.

Overheating is a product of the compressor overworking itself and that relates to the air dryer being plugged which you have resolved.

The good write up and excellent pictures are much appreciated.

Regarding the hand written numbers, yes they look like junkyard, but that is factory. It seems each compressor is hand assembled; also there are small upgrades over time that Hitachi and LR will not admit to re a formal new part number, hence they keep track of the units by what would probably be regarded as a build number - and it is hand written.

You will see that on most of the units. Below is from my previous compressor where the piston connecting rod broke.

More pictures are here.
DISCO3.CO.UK Photo Gallery - Broken Air Compressor RQG500060

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Great write up and thanks! I actually completed the removal and refill of my dryer desiccant a few weeks ago and took pictures to do a writeup, but i think this thread makes it a moot point to do so.

I will add a couple of notes though... when I took my dryer apart, I decided to simply use new desiccant. I did this for a few reasons, but first of all, the blue desiccant is apparently a carcinogen and since this stuff dissolves into dust over time, I didn't really want that floating around in my garage. So, I ordered a quart of new orange dryer desiccant (without the cobalt whatever) off ebay which turned out to be enough to do the dryer at least 3 if not 4 times (I won't buy this much next time). I think total cost was around $18 or so.

I also made sure to remove the filters and blow them out with compressed air. I made sure to blow from the outside of the filter to the inside in order to dislodge as must dust as possible. This was my method of "cleaning" them. Since part of the problem is these filters getting clogged with degraded desiccant over time, I figured best to clean them every time I have it apart. Finally, I made sure to clean the o-ring and mating surfaces as best I could before reassembly.

Result? Well, I didn't really have a problem before, so the end result is just less to think about for the next 2-3 years. I figure if I do this as preventive maintenance, then the compressor should last much longer. It seems as if the compressor in my car was actually replaced just over 2 years ago and there was already no sign of blue to the desiccant in the dryer... which I assume means they were completely saturated already.

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It's probably worth kitting up the proper amount of material and offering it as a kit. If you are not willing to do it, I'd be willing to do it if there were enough interest, unfortunately, to get to my canister I would need to drop my rock sliders. I'd at least post a link up for the material, if it's the right stuff.

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Connecting Rod Shot


LR3 not raising, even though I could trick the compressor into running a few times. Pressure seemed OK, and it would raise eventually, but I finally did a dead-head pressure test and found it wasn't even close to nominal spec.

Bought the compressor rebuild kit with guide rings, piston seal, desiccant, etc. I think it is by offered by X8R and on Amazon, the only one with the piston guide ring and seal, great kit btw. The video link from the product description was extremely helpful.


I need a new compressor. Once I waited for the rebuild kit, got the compressor off the LR3, and opened it up I found the piston cylinder worn on just one side. I pulled off the cylinder and the crank cover and found bits of metal floating around. The piston or 'wrist' pin was almost completely gone and the connecting rod was beat to death from hitting the lower part of the cylinder. Trashed. I really think the connecting rod bearing (to the crank) was what really went bad, as it is seized and won't spin at all. Cascading effect from there...

If you have a suspect compressor, pull the (4) bolts that hold the head and cylinder in place, with the crank access cover, and take a look at things. If it is all fairly clean, and the cylinder walls are OK, then the rebuild kits should work perfectly. Otherwise, just go for a new compressor. Getting a Dorman 949-900 for like $329 and will see from there.

Wish I had checked my compressor first, it would have saved me two weeks.

On that note, I wish I had:

1) Noticed the suspension drop overnight more diligently, and found any leaks right away (Wife's car, and I'm never home when she uses it). I should have done the fuse removal to freeze the height trick, as I would have learned a lot more about what was happening. Check YouTube for more info on that.
2) Done a pressure check right off the compressor first thing. This keeps you from taking half the car apart to look at the valves, ride height sensors, etc.
3) Checked the desiccant. It wasn't a factor in my situation and I'll get a new canister with the compressor.
4) Found the service manual sooner, so I could actually locate the front and rear valve blocks more expeditiously. (Front valve is on the rear of the right side front bumper, accessed by removing headlight, fender trim, and wheel well splash guard; rear valve is on the front of the shock pillar on the drivers rear side). Did a Google search to find it, and there is an excellent PDF called "Land Rover factory D3 air suspension description" that was the most helpful.

Later & good luck!

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Just curious if any of you have checked the specific error codes associated with the Amber and red fault messages. I had Amber light guessed it was compressor. Switched out for a Dorman compressor. Worked fine for a few days then Amber light quickly turning to red. Checked the codes and a had a couple. First was slow to rise which was probably the original and then the next was failure to release pressure, which recurrred after I cleared the codes with the dorman compressor. I'm rebuilding hitachi and putting it back in hopefully tonight. I have a feeling the Dorman exhaust valve got stuck. Will update after I get rebuilt hitachi back in. Thanks stuart

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Dorman, I don't know too much about the company have used a few other parts from them in the past. This 949-900 appears to be a Hitachi replica/ chinese made knock off. Seemed descent for $330 but expected more than 3 days.

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Replaced all available parts on Hitachi compressor(piston rebuild kit, dessicant, aluminum dryer cover, spring rebuild kit). But after about 45 seconds it starts to slow down and eventually sputters followed by Amber light and "slow to fill reservoir fault" I dissambled the electric motor portion and cleaned motor and brushes the best I could with still no avail. Fault doesn't come on when cold but if it heats up it behaves this way.

Switched for the AMK from meissler $450 but not OEM bracket or acoustic case, very noisy and vibrations are noticable. Raises very quickly with no faults though.

Wish I could have got more life out of my Hitachi, I'm out of ideas for it.

If I had to do it over I'd buy the $830 factory OEM AMK with case and call it a day.

Any other ideas for Hitachi?

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Just removed and rebuilt my compressor. PITA but easy overall. Remove the bracket with the compressor attached - use a ratcheting box wrench to get to the top bolt of the bracket, its inside of the air dryer, look up with a flash light. The other 2 bolts are easy. Press the flange where the air lines enter and the lines can be disconnected with a stiff tug. The rebuilt using the rebuild kit is very straight forward. Sone broil or PB might be needed for corroded screws. Vehicle rides like new - didn't realize id been riding in jello for 60K miles.
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