Suspension Faults

[101RRS]

For two consecutive days now I have had the orange suspension fault come up and the note that only onroad height is available. Switching off and back on clears the fault and everything is Ok for the rest of the day. So I guess it is the start of the process for the compressor to really start to degrade - 132,000km so I guess I cannot complain.

In anticipation of the compressor having issues I bought a full rebuild kit for the hitachi from X8 in the UK with the intention of rebuilding it while it was still running but never got around to it - so a job for next week following the great vids that X8 have produced.

So the compressor will have to come out - there is my problem.

A few years back I jacked the car up on the compressor and and broke the mount. To replace the mount I did not have to completely pull the compressor out but did have to release the rear pipes (inlet and ???) or thought I did.

Supposedly you only have to push in the little collets and pull the pipe out - well no it didnt go like that. Even with the collet pushed in (with WD40 and all) the pipes would not come out. I ended up cutting the the air intake pipe and later joined it with a piece of rubber fuel hose and managed to work around the other pipe in place.

This time the entire air compressor has to come out so all 4? pipes - two at the back and one or two (?) at the front have to be undone from their collets.

As the collets would not release last time, is there a trick to getting these little suckers to let go of the pipes.

Thanks

Garry

[Graeme]

The front pipes have screwed connections which are easy to undo, unlike the rear pipes with their push-in collets that get clogged with dirt preventing them from being pushed in far enough to release the pipe.

[DiscoJeffster]

Garry, let me know how it goes. My kit's been sitting on the shelf waiting for a need to use it. I've decided one day I'll pull it and just do it. Love to hear any tips.

[PerthDisco]

Mostly on the UK videos they have to cut and rejoin the pipes with special joiners. No problems with that solution. Mine all came out with WD40 and persistence.

I did find that you need to get your body in a tough position to work on the unit. I had access to a pit. Doing at ground level on a jack would be tough.

[Ean Austral]

Gday Garry,

I always thought the message centre showed a fault that said " compressor taking to long to inflate" or something along those lines if the compressor was on its way out , or have you actually identified it as a compressor fault thru the codes.
I battled suspension faults for ages that were very random but they did throw up a fault code , long story short , after replacing globes, brake light switches etc it was a battery issue.

I would have thought the compressor should last more than 132,000ks.

Cheers Ean

[DiscoJeffster]

I would have thought the compressor should last more than 132,000ks.

Cheers Ean

Age seems quite random. I guess it depends how much work it has to do - regularly off-road raising and lowering etc. Mines still ok at 7 years and 240k km but it spent a lot of that cruising the highways, so little usage.

[101RRS]

Thanks for the responses - others experience with the collets seem to be the same as mine - what a stupid arrangement - same as the filter/dessicant arrangement - why have this in the air compressor unit itself rather than a service item screw on canister (similar to an oil filter) on the side of the unit (just pull the bottom cover off to replace) or at the air intake end in the rear guard.

Ean - just checked the codes and the suspension fault light cam on straight away - also the air compressor was cycling in 2 sec cycles - 2 secs on 2 secs off but once the tank was full it ran normally in trying to keep the car level (car is a on a slope).

Codes
C1A13 Pressure does not decrease when venting the gallery
C1131 Intermittent air supply component failure
U1A13 Front right sensor - voltage out of range
CIA20 Pressure increase too slow when filling

I am not sure which are historic or are current as I have not checked the codes in about 4 years. I had battery issues last year and I think the sensor fault is related to that. The others seem to indicate a compressor issue rather than anything else.

I cleared the codes and none came back and the compressor was running and the car levelling BUT the tank is not full from when I first ran the car. I would expect at least C1A20 will come back in a little while - I need to go out in a bit so will check.

Ean on a side issue - remember we recently discussed remote EGRs and fault codes - well when checking the suspension stuff I checked engine codes - nothing there at all - so no issues with blanking EU4 engines with serviceable EGRs attached to the wiring loom.

Garry

[101RRS]

Just went for a drive down the auto elect for something else - no issues. Stopped for a cuppa and while parked dropped it down to acess height and then straight up to offroad height +50mm (have LLAMS) and went straight up except for the last few mm where the slow to fill message came up (note this is an advisory message not a fault message) - with LLAMs this is all normal and normally I stop at offroad height for a few minutes to get air into the tank then go the extra 50mm. I drove off at this high height and dropped it back down to access and then back up to the equivalent of super extended no issues. The dropped it down to access height again and back up to super extended ( this is really taxing the system and is not recommended) - above off road height the advisary message came up that raising height will resume when cooled - this is all normal and given three full cycles from access to 50mm above offroad shows that the basic system is OK.

When I got back home I put the Faultmate on to read the codes with nothing showing.

Open to any comments to assist with fault finding but in my mind the compressor is being strangled a bit from slightly blocked filters but is still working - if the tank is full it can keep air in there but if depleted it has trouble. I have two 4wd trips coming up in September and I dont want to go with a dodgy compressor. Next weeks job and if I am wrong it will give me time to go looking further.

Garry

[Ferret]

Pretty much identical behaviour as I was having. An overhaul with the X8 kit and I have had no further issues since.

Oh, and all hoses (front and rear) just popped off and refitted without problems.

[~Rich~]

For the service life the AMK compressor is giving I would not consider or bother rebuilding the Hitachi.

It's just that much better!!

[101RRS]

For the service life the AMK compressor is giving I would not consider or bother rebuilding the Hitachi.

It's just that much better!!

I have no experience with the AMK but from what I have read in overseas forums it doesn't seem to have been the saviour that we all thought. It seems that as it ages it is having similar problems to the hitachi though it does have better air output.

My compressor has lasted 10 years and I have the rebuild kit, which seems to have a good track record so I will go with that - if that does not work I will switch to the AMK.

Cheers

Garry

[Stuart02]

It's definitely not a leaky strut?

[Fatso]

My comp is still going ok 2007 RRS , i purchased a Dunlop compressor $479 from LRDirect as a spare when needed , cant be bothered with the soft ware change and the high price of the AMK .

[101RRS]

It's definitely not a leaky strut?

I think if it were a leaky strut that side would be dropping over a period of time and the fault code would be back.

Unless you can have a leaking strut and it not drop down?

Cheers

Garry

[Stuart02]

I think if it were a leaky strut that side would be dropping over a period of time and the fault code would be back.

Unless you can have a leaking strut and it not drop down?

Cheers

GarryOne of mine was throwing up suspension faults but obviously didn't have a big enough split to sag. I only knew it was that corner cos the other three had been replaced

[101RRS]

Just a bit of a follow up - since the two faults and then me raising and lowering the car over the full height range I have not had any issues at all. In that time I have covered about 1200km and checked the codes today and there are none - not even communications errors.

While the compressor is still running Ok I might do the rebuild as a precautionary measure so hopefully get a few more years.

Cheers

Garry

[101RRS]

This problem has not come back at all so not sure what was going on - so didn't bother rebuilding the compressor at this stage.

However last week the rear suspension went down to the bump stops overnight on a couple of occasions - only at night and not in the day. As it went down evenly on both sides an air leak in the airbags is unlikely. So was figuring the rear valve block might have leaks. However I went 4wding on the weekend with lots of extended and super extended height work (LLAMS) and since I have been back the suspension has not dropped.

So clearly not an airleak - I guess maybe an electrical issue when the car goes to sleep.

So open to suggestions - as indicated, has not dropped since a lot of use of the air suspension system.

This problem has happened once before about 18 months ago when the battery was dying but not had an issue since a new battery was installed.


Thanks

Garry

[Graeme]

My L322 goes down at the front overnight but it can be spotted part-way down late in the day. I have purchased a valve block rebuilt kit as I expect that air is escaping from the cross-link valve. The cross-link valves get very little air flowing through them normally but a good dose of cross-articulation can clean-out the seals. I suspect that pulverised desiccant from mine's Hitachi dryer has found its way into the front cross-link valve and that the cross-link valve seal to atmosphere also isn't sealing well. I hope to rebuild the valve block in a week or 2.

[101RRS]

Graeme - thanks - where did you get your rebuild kit from? If mine starts playing up again I will pull the EAS fuse to see if the issue is electrical or a leak and if a leak I will try rebuilding my rear valve.

Cheers

garry

[Graeme]

Valve block re-built kit
Discovery Air Suspension Valve O Ring Set of (3) RVH000095 RVH000055 RVH000046 | eBay (http://www.ebay.com.au/itm/Discovery-Air-Suspension-Valve-O-Ring-Set-of-3-RVH000095-RVH000055-RVH000046/282534689621'ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649)

[101RRS]

Thanks for that - car stayed up last night.

[Aussie Jeepster]

Thanks for that - car stayed up last night.

Maybe that's the problem, you are not letting it get a good sleep at night lol!

[Russrobe]

Valve block re-built kit
Discovery Air Suspension Valve O Ring Set of (3) RVH000095 RVH000055 RVH000046 | eBay (http://www.ebay.com.au/itm/Discovery-Air-Suspension-Valve-O-Ring-Set-of-3-RVH000095-RVH000055-RVH000046/282534689621'ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649)

Ah damn, was hoping we wouldn't need to pay so much for a few o-rings, I was tempted to remove them for sizing then go to Pirtek or the like to match them... I suppose for $42 delivered you get the piece of mind that they are the exact right size and you won't have to pull the thing apart again afterwards!
I might try this for my "jumping" rather than smooth raising that is happening in the rear of mine...

[crawal]

I rebuilt my old Hitachi with Ebay kit over 60k ago hasnt missed a beat.Simple job under 1 hour cheap fix [smilebigeye]

[101RRS]

Sorry for the long post.

Well I started this thread in Aug 2017 when I first started getting occasional faults on the suspension - went on like that for a long time, a few faults one after another then nothing for weeks. Went on like that until this week when the suspension started continually faulting about 2 minutes after start. While the 2 minutes were long enough to top up the air tank I was concerned that very soon the compressor was going to stop for good and if the suspension dropped I would be screwed.

Time to use that X8R Hitachi rebuild kit LAND ROVER DISCOVERY 3 4 RANGE ROVER SPORT AIR COMPRESSOR REPAIR KIT HITACHI (https://x8r.co.uk/products/land-rover/air-suspension-repair/land-rover-discovery-3-4-range-rover-sport-air-compressor-repair-kit-hitachi) that I have had for a number of years sitting on the shelf.

Pulled the compressor out - top bolt was not an issue, bottom front was though as I forgot how to get to it and it took me half an hour to work out what was obvious.[bigsad] The rear pipes are not an issue for me as I had to cut them years ago when I had to change the compressor mount as the connectors would not disconnect so I have both rear pipes connected at the cuts with fuel hose - they are both low pressure so not an issue.

So following the X8R video I did the piston first which was pretty straight forward, then did the desiccant which again was pretty straight forward. My old dessicant was white not blue with just a little powder - I think the powder comes from the dead beads being bounced around with car movement and forming the dust - not sure how it gets past the filters but it does, but I didn't have much.

Reassembled everything and tested and the everything ran fine on the bench.

I then loosely put everything back in and started up and right on queue after running for about a minute the same old suspension fault came back [bigsad]

Hmm time to get the faultmate out and actually reads the codes - hmmm not working the Fault mate has an operating temp range of 10 to 45 degrees and it had been sitting in the car which until I got in was at nearly 60 (outside was 40). So I could not check the codes - Faultmate went into the freezer to cool down for a while.

While thinking about the issue, I knew the compressor was not OK and there was not much power so unlikely to have got past the air tank the the front and rear valve blocks so I I thought I would pull the component that lives just in front of the compressor - not sure what it is but I assume some sort of valve block and sensors etc. Pulled it out and disassembled it and there was a fine coating of dust so I hit everything with compressed air then blew compressed air down all the connecting air lines.

I put everything back and started the car an let it run - no faults after 10 minutes - dissembling everything meant the air tank has been discharged completely and the air compressor just ran and ran as it does take a while to refill complete empty. Did a few height changes - going from access back to onroad I did a raising slowly message but no faults.

I got the Faultmate out of the freezer and checked the stored suspension codes and the only one was a communication error - nothing. So while the compressor definitely needed a rebuild it was still working and the dust probably stopped a sensor in the pump or the block I played with communicating with the ECU and so faulted.

Any way as it was dark and I need to connect everything back I could not actually take the car for a drive and I will do that tomorrow . So hoping all is good on the road.

On a side note I dont why someone has not come up with a remote desiccant container mounted separate from the compressor so that it could be easily changed as a service item. The current chamber could be left empty with the remote unit mount in the currrent pipe that goes from the outlet of the chamber to the nearby valve block. My current compressor lasted 12 years and 160,000km so if I still have the car when I do the next compressor rebuild I might thing about it.

Garry

[DiscoJeffster]

I think you answered that yourself. Develop something for a once in 12 year event? My suggestion would be that if you never want to buy a new compressor, you could always service it at the same time you’re supposed to change the flexible brake lines (six years). I serviced mine before any faults were showing to avoid getting stuck with a fault when I least needed it. Preventative maintenance style. That was a year ago and it’s not missed a beat

[Graeme]

I removed my D4's dryer without removing the compressor. The retaining screw can be removed using a stumpy Philips head screw-driver, after which the canister can be rotated to unclip it.

[101RRS]

Graeme - being a D4 that would have been an AMK i guess. Not familiar with them but if it can be changed without removing the compressor that would be great.

[Aussie Jeepster]

"On a side note I dont why someone has not come up with a remote desiccant container mounted separate from the compressor so that it could be easily changed as a service item. The current chamber could be left empty with the remote unit mount in the currrent pipe that goes from the outlet of the chamber to the nearby valve block. My current compressor lasted 12 years and 160,000km so if I still have the car when I do the next compressor rebuild I might thing about it."

Right on - I don't get this either. If its easy to get to, its easy to check and change before it becomes a problem.
I have a compressor kit now, and an overhaul is on the list (never ending) of things to do!
Alan

[DiscoJeffster]

Graeme - being a D4 that would have been an AMK i guess. Not familiar with them but if it can be changed without removing the compressor that would be great.

The Hitachi is also designed like that. One screw and a twist holds the desiccant/dryer in place. I can’t say how easy it would be to remove with it in situ.
https://uploads.tapatalk-cdn.com/20190125/87c351810750870c2610ec94e0f39ba2.jpg

[Graeme]

Graeme - being a D4 that would have been an AMK i guess. Not familiar with them but if it can be changed without removing the compressor that would be great.
Not initially an AMK. An AMK was fitted under warranty as the 3rd compressor just prior to the start of the general replacement program.

[101RRS]

Ok car running in the drive and changing heights and no issues.

I put everything back in and tightened up - again running in the drive no issues.

Went for a drive and for 15 minutes all was OK - then gong "normal height only" - plugged in the Faultmate and it showed 2 suspension faults.

1. U0416 - Invalid data received from vehicle dynamics control module - Bus signal failure, signal is invalid - pending

2. C1A20 - pressure increase too slow when filling reservoir - Algorithm based failure signed plausibility failure - permanent

Then in the 30 degree heat the Faultmate overheated and caused HDC, transfer case, gearbox and over heating faults that all disappeared when the Faultmate was removed from the OBD2 port.

So given the car was OK yesterday - what is the consensus of the issue? If I do get a new compressor am I still going to get these faults, given I essentially have a new compressor at the moment. Is there anything I should have replaced when I rebuilt the compressor.

Advice appreciated

Garry

[Graeme]

The pressure sensor for the reservoir has been known to give false readings. You could monitor the reservoir pressure, which should start to rise as soon as the vehicle is at the target height (normal/access/off-road) then continue rising with pressure slowing as it gets close to the cut-off pressure. If the pressure doesn't initially rise much even though the compressor is capable of raising the vehicle to off-road height at an earlier time then suspect the sensor. If the compressor stops to cool and you see the pressure dropping then the reservoir valve is not sealing.

Bear in mind though that the reservoir is held at a higher pressure than that required to get to off-road height.

[DiscoJeffster]

It may be possible you have a leak in the system somewhere making the compressor work harder and not achieve full pressure. Take Graeme’s advice and follow his steps to gather more data on the issue

[101RRS]

The pressure sensor for the reservoir has been known to give false readings. You could monitor the reservoir pressure, which should start to rise as soon as the vehicle is at the target height (normal/access/off-road) then continue rising with pressure slowing as it gets close to the cut-off pressure. If the pressure doesn't initially rise much even though the compressor is capable of raising the vehicle to off-road height at an earlier time then suspect the sensor. If the compressor stops to cool and you see the pressure dropping then the reservoir valve is not sealing.

Bear in mind though that the reservoir is held at a higher pressure than that required to get to off-road height.

Thanks - I will remove the valve block and clean out again as I agree with your logic - I just loosened the hose from the block to the air tank and there is lots of pressure in the tank which has now drained away - now I agree the pressure sensor needs checking/cleaning but without a Gap type tool how do i do what you have suggested above - i only have a code reader.

Thanks for your help - much appreciated

Garry

[101RRS]

Removed the valve block and cleaned it again though didn't need it.

Then same as yesterday - started up with no faults - I dropped from LLAMs -15 to access and then back up to normal onroad height - just gave the same slow rising message as to be expected with an empty tank.

Went for a drive moving up to LLAMS +30 and no issues and then back down to normal onroad height - 20km into the trip the fault came back - reset and 5km back, reset then 3km back, reset then 500m back and then basically the fauklt came back almost immediately on reset. It was the C1A20 fault.

So playing around with the valve does seem to fix the issue for a short period so you may be right Graeme. I guess you can buy Pressure Sensor by itself though I wonder if I should invest in a whole valve block as the little rubber seal at the bottom of the solenoid plunger looked well used.

I am gonna pull the air compressor back out and just double check that the cover on the desicant chamber did not cause an issue when I screwed it down as I could hear crunching inside, so maybe the supplier provided too many beads and coud be causeing a restricted airflow - I dont think so but I will check.

I did a leak test and all was OK around the valve block but where the pilot air pipe comes out of the dessicant chamber cover there was a leak from the orange connector but the blue air outlet was fine.

Garry

[Graeme]

Sorry, its so long since I used my Faultmate MSV that I had forgotten that not all Faultmates can show live values.

I also can't recall if an IIDtool can read live values on vehicles other than the one its registered to. I know they can read faults codes on other vehicles but you need live values.

[101RRS]

Thanks Graeme .

I took the compressor back out - it is surprising how quick you can do it when you are practised.

A few of the beads I had just put in had got cracked during the process of reinstallation but all seemed pretty normal - except for the colour of the beads. When I put them in the new beads were a brown colour, but when I took them back out after a day the top 2" of beads near the outlet were now green and the bottom 2" down near the piston were still brown. I put it all back but took teaspoons of beads out and the little bit of green dust that had formed when the beads were originally installed.

The pilot air pipe that comes out of the dessicant chamber cover is leaking from its orange connector - I cannot get the pipe out to reinstall it but very little air escapes but I will put a little sealant around to minimise it.

I bench tested the compressor, and with my finger over the outlet the airflow does not seem very strong. I can almost block it off but not quite - a little air still comes out so must be OK but I would have thought the pressure would have been higher - so maybe the rebuilt compressor is the issue.

Thanks for the contributions.

Garry

[Graeme]

Sounds like enough pressure to raise the suspension but not enough to get the reservoir up to pressure.

[101RRS]

Sounds like enough pressure to raise the suspension but not enough to get the reservoir up to pressure.

Yep - maybe time to bite the bullet and get a new compressor.

The obvious choice is the new AMK kit but they are about $1500 here and from the UK.

The cheaper ones, often sold as AMK type are knock offs ($600) RANGE ROVER SPORT AIR SUSPENSION COMPRESSOR KIT - COMPLETE - LR072537 -LR045251R | eBay (https://www.ebay.com.au/itm/RANGE-ROVER-SPORT-AIR-SUSPENSION-COMPRESSOR-KIT-COMPLETE-LR072537-LR045251R/183011534628'ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649) - and they may be OK but I dont know.

On the Hitachi side they are all knock-offs - Dunlop ($850), Bearmach and Britpart (I think these are Dunlops but I dont know) - mixed reviews on this lot.

Then there are the Chinese knock offs on Ebay like this For Land Rover Discovery 3 Hitachi Type Air Suspension Compressor Pump LR023964 6941503307842 | eBay (https://www.ebay.com.au/itm/For-Land-Rover-Discovery-3-Hitachi-Type-Air-Suspension-Compressor-Pump-LR023964/173740029663'ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649) - again may be OK but who knows.

Garry

[Graeme]

My son Justin bought an AMK from somewhere, possibly Germany, that was genuine AMK for a good price, much better than anywhere else. I'll prompt him to provide details.

[101RRS]

Time to put this puppy to bed.

I think you are on the money Graeme with your thought about getting enough air into the system to do things but not enough to keep the electronic geeks that live in the car happy.

Just put the compressor back in - same old story but this time the tank was full at the start - from onroad up to offroad no issues, down to access no issues, back up to onroad - hmmm dont like this will raise slowly but it got there and I could here the compressor stop - so up to full pressure. Now back up to off road - hmmm don't like this one little bit - up slowly - oops need a rest and will continue when I cool down - it is only 28 and the covers are not on the compressor. BUT - he gets there after a little rest - offroad height, compressor off and no faults so pressure must be there.

So back to onroad and off for a drive - 10km before gong - stopped a few times and some compressor running and sometimes not - all normal.

So it seems it can handle the ups and downs with just a little trouble when stopped but when driving cannot cope - I guess the constant level adjustment as you drive - along the lines as you suggested Graeme the compressor cannot keep the tank topped up quick enough for the car's electronic geeks.

I wasn't expecting the cooling issue today as I did not have it yesterday when it was the hottest January day in Canberra's history (42) and the covers were on. No covers today and needs to cool only after one lift.

So I need to decide what compressor to get - am leaning towards the AMK Type kit as I need the entire change over kit to fit the AMK. If the AMK Type compressor turns out to be a dud, a genuine AMK compressor without the rest of the kit is priced OK overseas (the same as a Dunlop).

Thanks for all the input - has been great.

Garry

[Fatso]

I just stuck with an hitachi compressor when i changed mine out after 11 yrs and rebuilt the old one with a kit for a spare , indi indicated that the Amk had just as many issues as the hitachi .

[101RRS]

I just stuck with an hitachi compressor when i changed mine out after 11 yrs and rebuilt the old one with a kit for a spare , indi indicated that the Amk had just as many issues as the hitachi .

Yes I have heard the same but you cannot buy Hitachi any longer - only their clones. There are plenty of AMK clones out there as well but if you want the original AMK is still available for a price.

Cheers

Garry

[Fatso]

Yes I have heard the same but you cannot buy Hitachi any longer - only their clones. There are plenty of AMK clones out there as well but if you want the original AMK is still available for a price.

Cheers

Garry

LRDirect UK have Hitachi compressor still listed LR023964 TR $347 . Thats where i got mine from 8 months ago .

[101RRS]

LRDirect UK have Hitachi compressor still listed LR023964 TR $347 . Thats where i got mine from 8 months ago .

Thanks - they are now $712 and you can only buy in lots of 2 - with GST and shipping comes to $1660 for two, so if you could get one it would be $830. I tried changing to numbers to 1 but the checkout auto changes back to 2.

Cheers

Garry

[coopers1969]

i too am in the same boat i have a Hitachi compressor that is struggling i am going to try the rebuild first see if that helps. My indy has quoted me 2500 for a AMK swap out and the cost of the compressor is 1600 which is about what it would cost me to get it here. fingers crossed that i the rebuild will give me a couple of years so i can save up and do the change over my self.

[Fatso]

Thanks - they are now $712 and you can only buy in lots of 2 - with GST and shipping comes to $1660 for two, so if you could get one it would be $830. I tried changing to numbers to 1 but the checkout auto changes back to 2.

Cheers

Garry

Sorry , said $ instead of Pounds . Bit silly gaving to buy two , wonder what thier price is for one then ? maybe an email is worth a try or see if anybody else can go halves for 2 .

Britcar have Hitachi for 487 pounds LR072537 which appaerently supercedes LR023964 ? so Hitachi are still out there . Glad i got in before the GST came in last year and bought up some stuff to get me out of trouble if need be .

Good luck with it .

[101RRS]

My indy has quoted me 2500 for a AMK swap out and the cost of the compressor is 1600 which is about what it would cost me to get it here.'

$900 labour seems quite excessive - about 1/2 hour to drop the old one, maybe an hour to put the new one in and then the software upgrade - I would have throught less than haif the quoted cost. Of course you could go a AMK knockoff kit for about $600 delivered.

[Fatso]

'

$900 labour seems quite excessive - about 1/2 hour to drop the old one, maybe an hour to put the new one in and then the software upgrade - I would have throught less than haif the quoted cost. Of course you could go a AMK knockoff kit for about $600 delivered.

Notice that TR Spares in Sydney have Hitachi LRO23964 in stock for $825 . Not a bad price , can buy online .

[101RRS]

Just a side question - all the "experts" say the relay should also be changed - why? I mean it is a relay to provide power to the compressor - if the relay fails the compresor doesn't run at all - pretty obvious. I have had relays fail occasionally but overall they are pretty reliable. If the compressor relay should be changed on a regular basis why not other relays in the car system.

The relay right next to the compressor relay is exactly the same spec and part number and we do not change it - I did swap them around and it made no difference.

So if the relay is working OK why does it need to be changed?

Oh trying one last thing - have ordered a metal cap for the Hitachi to correct the air leak from the pilot air pipe connector just in case that is the issue - i dont think so but worth a try before I spend big bucks.

Garry

[Graeme]

What's the current rating on a relay for an Hitachi and one for the AMK? I thought the AMK was rated higher but perhaps by the time a compressor needs replacing the relay contacts are well worn and possibly cooked from the excessive running of an inadequate compressor.

[101RRS]

As a last resort I bought the stainless desicant chamber end cap and an exhaust valve rebuild kit to see if they may have been the issue.

Put the cap on today - made absolutely no difference (nice piece of kit though) - fault came back soon after starting. I tried to get the exhaust valve out but just ended up wrecking it [bigsad].

As I noticed it is very hard to blow through the felt filters so as the fault I have been getting is C1A20 - pressure increases too slow when filling reservoir I thought that as it is a nice warm, very dry day I would try and run the air compressor without any desicant or felt filters to see if they were the issue - nope faulted straight away.

So I have a new "ring" on the compressor piston, (the cylinder is perfect - still has the hone marks) new desicant, new filters, new end cap and the system still throughs up the C1A20 - pressure increases too slow when filling reservoir - there are no leaks in the compressor system nor elsewhere in the car (drove 1000km on Wed with no compressor running and height was fine).

So - why isn't this compressor not getting enough pressure up - who knows. Is there an issue with the pressure sender in the main valve block - again who knows as there are no specific codes showing for this.

I understand there is a software update for the Hitachi to lower operating pressure but no one seems to know about it.

Time to bite the bullet so i am going to order a knock off AMK kit and see what happens. If I still get the same "C1A20 - pressure increases too slow when filling reservoir" code after I have the AMK clone and its soiftware installed and the I might look at the pressure sensor.

Thanks for all the input [thumbsupbig]

Garry

Ps - the compressor runs fine - just cannot quite get enough pressure (it will lift the car to extended height) - what else can I use this compressor for noting I already have two normal tyre type 12v compressors at home?

[Graeme]

Can you monitor the reservoir pressure to see what it starts at and if it is actually increasing?

[PerthDisco]

Duckworths, I believe, sells the original Hitachi unit which would have to be easiest R&R without change of pipe connections or software?

[IvanR]

Check to see if your air tank as a plug at the front end, if so then you could plumb in a gauge to check pressures.

Ivan

[101RRS]

Can you monitor the reservoir pressure to see what it starts at and if it is actually increasing?

I do not have the means of doing that but by inference I know the compressor is filling the tank. If I bleed the tank, the compressor fills it and I am able to go up and down without fault from the compressor (so the tank must be getting full and at a high pressure) - it is (as we discussed before) when I have stopped playing around with heights and just driving along that the fault comes up - your earlier thought that it is just not enough to keep the tank topped up with that bit extra pressure to cover self levelling when driving I suspect is on the money. The reason for this I am not sure.

When playing around with exhaust relief valve system I broke off the hexagon head [bigsad]. I thought not such an issue as the metal plug with the spring and seal is still in place but air comes out the plug so maybe that is where my pressure loss is - the exhaust relief valve could be leaking.

But it is time to cut my losses on this.

Thanks for your help - much appreciated

[101RRS]

Duckworths, I believe, sells the original Hitachi unit which would have to be easiest R&R without change of pipe connections or software?

Thanks - nothing comes up on their site using their search function but then if you just type in air compressor nothing comes up either.

[justinc]

Garry direct sales to the public places like Airbagman in QLD sell the Dunlop version, can't remember if you get the bracket with them . At least you will get a warranty buying local...
I will put money on it being a dodgy pressure sensor, the one integral with the pump...🤬

[101RRS]

Ok time for me to cry wolf again and again [smilebigeye].

I have just been for a 70km drive with no faults. [bigsmile1]

Today I tried to take out the exhaust valve to put in a new spring and seals.

However everything was stuck and I managed to rip the hex head off it [bigsad]
148927148928

Researching further I found this is quite common. Initially I though it would be Ok as the plug was still in the threaded section but when I ran the compressor and leak tested the area it bubbled up big time. Now as the compressor was under no load, the exhaust valve was closed as it should have been there should have not been any leak.

At this point the light came on - I figured that the exhaust valve was stuck slightly open, dumping some air from the piston out the exhaust rather than into the suspension system - but only open a little as decent pressure was still getting into the sytem.

So I tried to remove the plug by hitting it with a big hammer and a screw driver to turn it - no luck, then a little heat and no luck - so time to order that new compressor which would take a few weeks to arrive.

The old compressor needs to go back in while a new one arrives, so I had to seal the plug so that the compressor would provide at least some air from start to when it faults usually 5 min after start - tops up the tank.

So I super glued [thumbsupbig] the hex nut back in, and covered the lot with sealant and guess what - it sealed it.

Compressor back in the car (now down to less than 5 mins to get back in). For the usual test drive - normally takes about 10km to fault when the system has been tinkered with. This time after 70km and 90 minutes no faults - no issues raiseing and lowering and no slow rising messages as I had before.

My take is that the area around the exhaust valve is prone to internal corrosion due to humid exhaust air from the system. Corrosion was either holding the valve open a little or preventing it from closing completely. Me bashing the crap out of it had dislodged the valve and it now seals but probably not for long.

I will now order a new exhaust valve housing and drill out the plug that is in there at the moment - a new compressor is on hold for the moment.

[101RRS]

Been driving around the last couple of days and no faults. So my guess that the exhaust valve was cracked open just enough to stop the system getting to full pressure was probably right.

So if you rebuild your air compressor and it still faults with "normal height only" C1A20 - pressure increases too slow when filling reservoir then also check your exhaust valve.

I have ordered a new exhaust valve housing (already have the new spring and seals) so the decision will be - do I tempt Mr Murphy and drop the compressor and replace the housing and seals risking further mayhem, or do I also tempt Mr Murphy and let the superglue continue to do its work and leave things as they are and only 'permanently' fix it if it plays up again - noting the car will still drive but not be able to do height changes on the move.

One aspect of this long saga is that I have learnt the ins and out of these compressors and with the exception of a physical failure of say the electric motor or the conrod etc there is no real reason to replace them when they fault as all the wear components are available.

Garry

[Eric SDV6SE]

Good to know Garry,

AFAIK the compressor in mine is still original,I need to put a kit through it if I want it to last another 9 years.

i have done the regular clean of the externals and to date have not had any compressor faults (touch wood), I must say your posts have been very helpful

[101RRS]

So just and update - been three weeks now and no issues - fault fixed so must have been as I surmised.

I still have not put the covers on the compressor so can here what is going on. Compressor always runs on start - short or long depending on air in the tank. Some say in a good system the compressor should not run if there is no air loss - but the system is constantly farting depoending on what is happening - temp lowers over night and pressure reduces so compressor tops it up on start, likewise occassional it will fart when the car wakes up and checks level and may fart.

On start the compressor runs and normally there is a fart, when you stop on the level or on a slope it will fart as part of the self level function - and occasionally when shut down it will fart when the car wakes up.

Though harder to hear because of road noise - the car is constantly self levelling - compressor running for short period and farting to reduce pressure - you miss this with the covers on and the windows up.

This process has been extremely educational, I never realised that there is only one pipe to the reservoir - so air goes into the tank in one pipe but comes out through the same pipe, the most important component in the system (other than the ECU) is the central control block shuttling air to where it is needed. The last interesting thing is why does the desiccant last so long (in my case 12 years)? You go to Woolies and buy some to get rid of damp in your cupboard and it only lasts a couple of months max - well in the car system it takes what is normally dehumidified air from the rear of the cabin (assuming you have climate control on), whatever water is still in the air is captured by the desiccant after the pump but it lasts and lasts - this is because when the system vents the dehumidified air from the air bags etc - it is not straight to atmosphere but it goes back into the desiccant chamber and sucks out some of the moisture in the beads before venting to atmosphere.

Really if you have the time to wait for parts, there is really no reason to buy a new compressor.

Anyone got a dead Hitachi they want to sell me cheap [biggrin]

Garry