Air Compressor Rebuild ??

[Ean Austral]

Gday All,

Noticed my Hitachi compressor is started to run a bit longer than normal so I am going to pull it out and give it a once over. I have the new kit to do the air dryer but am wondering if others have done more than just change the disscasnt and the filters . Can anyone let me know where to get the other parts if required

Cheers Ean

[101RRS]

These guys have kits to do full rebuilds and have videos to show how to do it.

Air Suspension Repair (https://x8r.co.uk/products/land-rover/air-suspension-repair)

Garry

[justinc]

Ean ive not had much success however the bits are cheap enough to diy.

☺jc

[Ean Austral]

Ean ive not had much success however the bits are cheap enough to diy.

☺jc

Gday Justin,

For the cost of the parts I will give it a go. Nothing ventured nothing gained I guess.

Cheers Ean

[justinc]

Of course. I don't do them anymore as it approaches an uneconomical level adding labour and having to be able to offer a warranty on the rrpair. Also have had a few with electric motor failures too that is really a throwaway.

Hope it works out. Id be getting the full kit not just the drier refurbishment.

Jc

[Ean Austral]

Of course. I don't do them anymore as it approaches an uneconomical level adding labour and having to be able to offer a warranty on the rrpair. Also have had a few with electric motor failures too that is really a throwaway.

Hope it works out. Id be getting the full kit not just the drier refurbishment.

Jc

Thanks Mate, yep I ordered the full kit and if I do it myself and it stuffs up then no one to blame but me. It hasn't thrown up any warnings yet but I just noticed today it ran just that little bit more than normal , and it is 10 yrs old so prolly due for a bit of attention. Once I strip it down if it looks to far gone I will just get a new one.

Cheers Ean

[DiscoJeffster]

Recently did a full kit myself at home and spent more time getting the top bolt out and in than the whole rebuild process. So far so good.

[justinc]

Recently did a full kit myself at home and spent more time getting the top bolt out and in than the whole rebuild process. So far so good.

Slot the top hole in the bracket before refitting.

Jc

[crawal]

Recently did a full kit myself at home and spent more time getting the top bolt out and in than the whole rebuild process. So far so good.

Me too big PITA [bighmmm]
but kit is still working after 80k fitted full kit

[Grappler]

Is it feasible to refurb the valve blocks. I have found an o ring kit for all 3 valve blocks sourced from USA

Has anyone refurbed the blocks successfully and are kits available in Australia?

After testing sag overnight with he #3 fuse pulled out the two front bags dropped equally 55mm the rear grew a few mm:confused:
I believe this is probably caused by an internal leak in the front valve block, so Im thinking giving the valves a birthday could be worth a try

[justinc]

Id be thoroughly soaping the front bags first. How old is you car?

Jc

[Grappler]

Yes will do that too (soap bubble test) as the bags have done over 200K. What is a recommended airstrut replacement.? Ive been looking at Arnott from USA but will be exxy. What is the consensus on air struts?
Seems odd that both front bags sag at the same rate with the equalising solenoid disabled, but its not implausible for both front bags have similar leakage

[justinc]

Only decent results i have had are with Delphi ones.

Pay good $ for good parts not worth skimping on bits for these cars its not a bleedin camry...😅

[Grappler]

Only decent results i have had are with Delphi ones.

Pay good $ for good parts not worth skimping on bits for these cars its not a bleedin camry...😅

You are right. The original delphis are still working after more than 200K and and 11 years with a daily run on our corried access road The Arnott replacements get a good writeup (on their own site) but was hoping for some independent review here

I intend to do some more diagnostics by isolating each corner with and isolation valve, overnight, to check the solenoid valves are not an issue.
Im away from home so dont have my verniers,so my rough measure of the air lines is 6mm OD Can someone confirm the OD of the lines so I can get the correct push fit parts

[veebs]

If the original bags lasted over 200k km, I'd consider them to be pretty damn good, and so worth going OEM again?

[donh54]

AFAIK Delphi was the OEM supplier. I think they were badged as Contitech, too.

[justinc]

Its not just the airbag. The shockabsorber has to be of high quality too.

Jc

[matt_ali_walsh]

I Got Delphi struts from Duckworths. Not worth stuffing about IMHO, given the price - quite reasonable I thought. Saved about $1000 on buying Dunlop struts locally.......

[Lukeis]

I have a rebuilt hitachi compressor which never fixed itself, I’m pretty sure because the piston seal isn’t snug enough to keep the pressure so I ended up buying the AMK one instead

The compressor works (as in runs) and the dryer, decidessant and pads are all brand new, plus the dryer cap has the new alloy top on it instead of the plastic one so lots of usable parts

free to a good home if you want to pick it up - northern beaches Sydney

[Geedublya]

I have a rebuilt hitachi compressor which never fixed itself, I’m pretty sure because the piston seal isn’t snug enough to keep the pressure so I ended up buying the AMK one instead

The compressor works (as in runs) and the dryer, decidessant and pads are all brand new, plus the dryer cap has the new alloy top on it instead of the plastic one so lots of usable parts

free to a good home if you want to pick it up - northern beaches Sydney

Hey Luke, I sent you a PM.

[Grappler]

Im just looking for an opportunity to replace the front struts and the front levelling valve. I have all the parts at hand. I can see they are fitted with a type of Voss connector. Are the fittings on the new parts shipping blanks. Do I fit the air line to the new fittings or do I reuse the existing connectors fitted on the air lines?
Any advise appreciated

[DiscoJeffster]

Front struts come with new voss connectors. I’m not sure about the valve blocks. You unscrew the voss connector on the old strut, then remove it and the collet so you just have the air line. On the new one you remove the blanking/dirt cover (white insert) then push in the air line up until the limit point (raised ridge).

[Grappler]

Been working through giving the EAS a birthday. Replaced front struts and levelling valve that had white desiccant dust contamination. Had a major fail today trying to refurb the Hitachi compressor. I broke the top of the piston attempting to prise the ring seal retainer off. My better judgement said the instructional video on the kit suppliers website looked dodgy but I went ahead anyway[bighmmm]. The vehicle will have to stay on the hoist till I work out a solution. I ordered a piston and cylinder kit from USA

[loanrangie]

Is there an easy way to determine which compressor i have on an MY08 D3 ?

[shanegtr]

Been working through giving the EAS a birthday. Replaced front struts and levelling valve that had white desiccant dust contamination. Had a major fail today trying to refurb the Hitachi compressor. I broke the top of the piston attempting to prise the ring seal retainer off. My better judgement said the instructional video on the kit suppliers website looked dodgy but I went ahead anyway[bighmmm]. The vehicle will have to stay on the hoist till I work out a solution. I ordered a piston and cylinder kit from USA
I recently had my compressor fail - cylinder was stuffed. didnt realise that spare piston cylinder kits where available. Will have to order a set myself now and rebuild my old compressor for a spare.

[Grappler]

I recently had my compressor fail - cylinder was stuffed. didnt realise that spare piston cylinder kits where available. Will have to order a set myself now and rebuild my old compressor for a spare.
This is what I have on order Hopefully it will do the trick I will post how the repair goes
LAND ROVER LR3 05-09 & LR4 10-12 AIR SUSPENSION COMPRESSOR CYLINDER REPAIR KIT | eBay (https://www.ebay.com.au/itm/LAND-ROVER-LR3-05-09-LR4-10-12-AIR-SUSPENSION-COMPRESSOR-CYLINDER-REPAIR-KIT-/162655550418?_trksid=p2385738.m4383.l4275.c10)

[101RRS]

This is what I have on order Hopefully it will do the trick I will post how the repair goes
LAND ROVER LR3 05-09 & LR4 10-12 AIR SUSPENSION COMPRESSOR CYLINDER REPAIR KIT | eBay (https://www.ebay.com.au/itm/LAND-ROVER-LR3-05-09-LR4-10-12-AIR-SUSPENSION-COMPRESSOR-CYLINDER-REPAIR-KIT-/162655550418?_trksid=p2385738.m4383.l4275.c10)

That will suit a catastrophic failure but doesn't include the bits that most commonly fail like the dessicant, filters etc etc. It is rare that the actual piston and conrod fails - if it did you would be better just getting a new compressor.

For a rebuild you will most likely need these parts that are not included in the repair kit above.

Land Rover Discovery 3 4 Range Rover Sport Air Compressor Repair Kit Hitachi & End Cap (https://x8r.co.uk/products/land-rover/air-suspension-repair/land-rover-discovery-3-4-range-rover-sport-air-compressor-repair-kit-hitachi-end-cap)

[rangieman]

That will suit a catastrophic failure but doesn't include the bits that most commonly fail like the dessicant, filters etc etc. It is rare that the actual piston and conrod fails - if it did you would be better just getting a new compressor.

For a rebuild you will most likely need these parts that are not included in the repair kit above.

Land Rover Discovery 3 4 Range Rover Sport Air Compressor Repair Kit Hitachi & End Cap (https://x8r.co.uk/products/land-rover/air-suspension-repair/land-rover-discovery-3-4-range-rover-sport-air-compressor-repair-kit-hitachi-end-cap)
Wow both kits add up towards $300.00 Aus approx plus postage could end up around the $400.00 plus with postage for a full kit is it really worth it :Thump:.
What is a new compressor worth [bigwhistle]

[loanrangie]

Wow both kits add up towards $300.00 Aus approx plus postage could end up around the $400.00 plus with postage for a full kit is it really worth it :Thump:.
What is a new compressor worth [bigwhistle]

And that doesnt include the motor so probably better off with a new one.

[DiscoJeffster]

If you read the original post you’ll see the dude damaged the piston as part of the simpler rebuild. At that point I might have questioned the value of repairing, however having already invested in the standard rebuild kit I guess in for a penny, in for a pound.
The standard rebuild costs about $100 and works a treat. I did mine proactively with no issue.

[Ean Austral]

Doing mine tomorrow , got the BONG today and took ages to find the fault but it was too slow to rise or something like that.

See how it goes.

Cheers Ean

[101RRS]

If you read the original post you’ll see the dude damaged the piston as part of the simpler rebuild.

But is the piston actually damaged or the replaceable wrap around ring bit that surrounds the actual metal piston? The wrap is part of the standard kit.

[DiscoJeffster]

But is the piston actually damaged or the replaceable wrap around ring bit that surrounds the actual metal piston? The wrap is part of the standard kit.

Grappler posted
“Had a major fail today trying to refurb the Hitachi compressor. I broke the top of the piston attempting to prise the ring seal retainer off.”

[101RRS]

Grappler posted
“Had a major fail today trying to refurb the Hitachi compressor. I broke the top of the piston attempting to prise the ring seal retainer off.”

Oh Ok - there are a couple of different threads of conversation - I did not see Grapplers post as I was following Shanegtr


I recently had my compressor fail - cylinder was stuffed. didnt realise that spare piston cylinder kits where available. Will have to order a set myself now and rebuild my old compressor for a spare.

Hence Grapplers response on getting a piston and conrod kit did not seem appropriate to fix Shanegtr's problem but is clearly what he needs.

All makes sense now - thanks - in Grapplers case I think a a new compressor is the best option - as both kits are now needed and for not much more you can get a new compressor.

I hope is all works out Ok for Ean, Grappler and Shanegtr [bigsmile1].

My Compressor is now 10 years old and still running - apparently OK and I have a rebuild kit to go in when I get motivated. After new brakes, steel pan on the gearbox, put the RAI on and install the electric brake controller.

Garry

[DiscoJeffster]

Garry. I would do it now if you have the kit. The sooner you change the desiccant the less likely you’ll have other complications. The filters should stop the fine powder from the failing desiccant affecting the rest of the system, but this hasn’t been the case for everyone. I did mine proactively so it didn’t fail in the middle of nowhere or cause other issues.

[shanegtr]

Oh Ok - there are a couple of different threads of conversation - I did not see Grapplers post as I was following Shanegtr



Hence Grapplers response on getting a piston and conrod kit did not seem appropriate to fix Shanegtr's problem but is clearly what he needs.

All makes sense now - thanks - in Grapplers case I think a a new compressor is the best option - as both kits are now needed and for not much more you can get a new compressor.

I hope is all works out Ok for Ean, Grappler and Shanegtr [bigsmile1].

My Compressor is now 10 years old and still running - apparently OK and I have a rebuild kit to go in when I get motivated. After new brakes, steel pan on the gearbox, put the RAI on and install the electric brake controller.

Garry
Well my issue is sorted as I purchased a new compressor, but I would still like to rebuild my old one for a spare - stuffed cylinder so the replacement piston and cylinder would sort it - and the old one already has new desicant too.

[Ean Austral]

mmmm well the job is easy enough to do , but sadly I have an air leak out of both the fittings on the end cap of the dryer .

Rebuild was straight forward , and I was surprised that a lot of the disscant was still quite solid but there was signs of it having turned to like a fine grain sand.

Will have a bit more of a play and see if I can get this to seal.

Cheers Ean

[DiscoJeffster]

mmmm well the job is easy enough to do , but sadly I have an air leak out of both the fittings on the end cap of the dryer .

Rebuild was straight forward , and I was surprised that a lot of the disscant was still quite solid but there was signs of it having turned to like a fine grain sand.

Will have a bit more of a play and see if I can get this to seal.

Cheers Ean

Did your kit come with a new aluminium end cap? If so, I have an idea for you.

[Ean Austral]

Did your kit come with a new aluminium end cap? If so, I have an idea for you.

No I was a tight arse just bought the basic kit .

cheers Ean

[Ean Austral]

So some thoughts on the rebuild.

I attacked mine as I had the fault of the compressor taking to long to build pressure or something similar to that. I had already ordered the rebuild kit - albeit without a new dryer end cap - and the rebuild wasn't that difficult and I think in hindsight it wasn't really in need of a rebuild . With the install I had the fittings leaking in the dryer end cap which I managed to fix with some new pipe and a couple of joiners .

Low and behold start it up and all good for about 3 or 4 minutes and I hear the compressor start up. I did some leak checks and sure enough there is a crack in the end cap and its leaking enough to have the pressure drop in a couple of minutes. In all honesty I think this may have been the initial problem , as I took great care removing the cap and altho not impossible it could have cracked on removal , I think it unlikely.

Ordered a new end cap today , and covered the other in some epoxy to see if that will hold till the new one arrives , but if I could go back knowing what I know now I would check it for leaks/cracks before assuming it needed a rebuild.

Just my 2c worth

Cheers Ean

[Ean Austral]

https://www.aulro.com/afvb/images/imported/2018/03/166.jpg

This is when I first opened the top of the dryer, some of the crushed dissicant

https://www.aulro.com/afvb/images/imported/2018/03/167.jpg

This is the stuff that came out from under the metal top filter , it looks in good condition but I am unsure if it has changed colour with moisture or not. the new stuff was a dark green colour

https://www.aulro.com/afvb/images/imported/2018/03/168.jpg

The filter pad directly above the compressor , so at the bottom of the dryer. not sure if its black from compressor exhaust or heat but the pads themselves were not to bad.
Car is a 01/08 D3 and to my knowledge the compressor has never been removed.

Cheers Ean

[Fatso]

So some thoughts on the rebuild. I attacked mine as I had the fault of the compressor taking to long to build pressure or something similar to that. I had already ordered the rebuild kit - albeit without a new dryer end cap - and the rebuild wasn't that difficult and I think in hindsight it wasn't really in need of a rebuild . With the install I had the fittings leaking in the dryer end cap which I managed to fix with some new pipe and a couple of joiners . Low and behold start it up and all good for about 3 or 4 minutes and I hear the compressor start up. I did some leak checks and sure enough there is a crack in the end cap and its leaking enough to have the pressure drop in a couple of minutes. In all honesty I think this may have been the initial problem , as I took great care removing the cap and altho not impossible it could have cracked on removal , I think it unlikely. Ordered a new end cap today , and covered the other in some epoxy to see if that will hold till the new one arrives , but if I could go back knowing what I know now I would check it for leaks/cracks before assuming it needed a rebuild. Just my 2c worth Cheers Ean

Good job Ean , had the same (to slow to pump up etc ) about 12 months ago and on checking found a leak on the front valve block , ok after fixing that .
My compressor is now 10 yrs and is going well but was a bit concerned about the stuff in the dryer but looking at yours i might just leave it untill something says different , ( the old saying dont fix it if it aint broke ) Perth is a bit dryer than Dawin so the desicant or what ever you call it should be ok . Thanks for posting the Pics much appreciated . Al

[Grappler]

Been working through giving the EAS a birthday. Replaced front struts and levelling valve that had white desiccant dust contamination. Had a major fail today trying to refurb the Hitachi compressor. I broke the top of the piston attempting to prise the ring seal retainer off. My better judgement said the instructional video on the kit suppliers website looked dodgy but I went ahead anyway[bighmmm]. The vehicle will have to stay on the hoist till I work out a solution. I ordered a piston and cylinder kit from USA

Piston and cylinder arrived in less than a week (quicker than from East coast Aus). Apart from needing to machine the wrist pin holes out to make an interference fit, the assembly was straight forward
I had already refurbed the air drier, which included the upgraded o ring carrier between the perforated metal plates and an upgraded drier cap. The improved o ring holder will reduce the powdered silica bypassing like in Eans pics.
After putting back under the vehicle, the air system recharged from empty in a few minutes and no bubbles.
Only time will tell if this has been an economical exercise.

[MUMSRIG]

Hi there Luke,

is is your compressor still available mate?

sent you a PM but your inbox is full apparently?

cheers

Mitch



I have a rebuilt hitachi compressor which never fixed itself, I’m pretty sure because the piston seal isn’t snug enough to keep the pressure so I ended up buying the AMK one instead

The compressor works (as in runs) and the dryer, decidessant and pads are all brand new, plus the dryer cap has the new alloy top on it instead of the plastic one so lots of usable parts

free to a good home if you want to pick it up - northern beaches Sydney

[MUMSRIG]

I pulled my compressor out this week and checked the air dryer....

this is is what I found

150400

150401

150402

The dryer was almost completely blocked so I’ve ordered a new one.

Mitch

[nigel1515]

I notice that no one`s mentioned whether the system needs to be de-pressured before compressor removal, but some where I read that it needs to be!! Is this true??

[Bulletman]

I've done mine both as a full rebuild and a couple of dissicant changes and never de-pressurised the system.

Bulletman

[DieselLSE]

I notice that no one`s mentioned whether the system needs to be de-pressured before compressor removal, but some where I read that it needs to be!! Is this true??
There's a non-return valve immediately downstream of the compressor assembly, so there's no need to de-pressurise the rest of the system if only the compressor assembly is being worked on.

[Eric SDV6SE]

I notice that no one`s mentioned whether the system needs to be de-pressured before compressor removal, but some where I read that it needs to be!! Is this true??

By the time you pull the compressor out after you've disconnected the airlines there's no air pressure on the compressor side. The NRV keeps pressure in the circuit.

No issue to deflate all EAS bags and the circuit though, that's what I did, took the rebuilt compressor about a minute to refill, IMHO a good test of the system.

[101RRS]

No need to repressurise the system - I drove around for approx 1000km with no compressor fitted at all - just need to be happy that the system will hold pressure, it does lose a little each time it height adjusts though.

However if you are going to change the desiccant you will probably need to depressurise to clean out the central valve block of desiccant dust.

Garry

[nigel1515]

I would imagine the air tank gets the bolt on the end cracked open slightly and de-pressurise the system. Think that might be the next job!![bigsmile1]

[101RRS]

Just crack the air line on the central valve block until you hear the hiss and then leave it until the hiss stops.

[Eric SDV6SE]

Or use your gap or rovacom tool and it's done in less than 30 seconds and you know it empty.

[haydent]

Has anybody fitted or considered adding a connection to the compressor or tank so you can fill tyres from it ??

[DiscoJeffster]

Has anybody fitted or considered adding a connection to the compressor or tank so you can fill tyres from it ??

It’s a low flow, high pressure compressor, completely the opposite of what you want in a tyre compressor.

[haydent]

ok makes sense, but what about if the tank reservoir ?

[Eric SDV6SE]

ok makes sense, but what about if the tank reservoir ?

Clearly not to you.

You will burn out your compressor quick smart as it tries to keep up the air supply to the tank.

I say go for it and let us know...

[haydent]

im thinking more for just topups that filling a deflated tyre

[BradC]

im thinking more for just topups that filling a deflated tyre

The tank sits at 16.8 bar. A bit of plumbing required to make that work.

Aside from the previous comments on "don't do that, the compressor isn't designed for it" :

When the system pumps up, it brings air in, compresses it and pushes it through the dryer. When it farts, it takes that compressed, dry air and pushes it back through the dryer, ejecting some of the adsorbed moisture. It's a closed system.

If you go taking air from the closed system, you'll quickly saturate the dryer.

A quick calculation of my 255/55/R19 tyres would indicate a volume of somewhere in the order of 70L of air at atmospheric pressure (116L total volume minus 46L rim).

At 25psi, that's ~119L and at 40PSI that's 190L. So I'd need ~71L to go from 25->40 PSI.

The tank on the car is ~9L @ 16.8bar, so ~151L when full.

What do you define as a "topup" ?

[101RRS]

There must be a zquillion posts on this on the forum.

[DiscoJeffster]

There must be a zquillion posts on this on the forum.

+1

[101RRS]

Though I did get a flat in my mum's driveway last year. I carry a tyre repair kit with me and was going to us the threads to fix the tyre in place but then remembered I had no way to pump the tyre up so had to go through the horrible process of putting the spare on and getting the tyre place to fix.

After that I did some basic calcs and worked out that a full suspension air tank would be able to get enough air into one tyre to make it driveable - not as a replacement for an offroad air compressor but as an emergency device to pump up one tyre. Would probably work.

But then, the more I thought about it - I figured it would be easier again to just carry a cheap ebay twin cylinder air compressor in the back - is a little slow but will do all my 101 tyres. So I now carry the air compressor in the boot just for these onroad emergencies - for offroad I have my top of the range Aldi single cylinder air compressor that is fast and never failed[happycry].

[Eric SDV6SE]

There must be a zquillion posts on this on the forum.

Zquillion and 2 now

[haydent]

The tank sits at 16.8 bar. A bit of plumbing required to make that work.

Aside from the previous comments on "don't do that, the compressor isn't designed for it" :

When the system pumps up, it brings air in, compresses it and pushes it through the dryer. When it farts, it takes that compressed, dry air and pushes it back through the dryer, ejecting some of the adsorbed moisture. It's a closed system.

If you go taking air from the closed system, you'll quickly saturate the dryer.

A quick calculation of my 255/55/R19 tyres would indicate a volume of somewhere in the order of 70L of air at atmospheric pressure (116L total volume minus 46L rim).

At 25psi, that's ~119L and at 40PSI that's 190L. So I'd need ~71L to go from 25->40 PSI.

The tank on the car is ~9L @ 16.8bar, so ~151L when full.

What do you define as a "topup" ?

ok not ideal then. and i guess even if you had the outlet at the pump its still going through the desiccant, unless you tapped in between the pump and desiccant if possible.

anyway enough thread hijacking, i did order a desiccant/filter kit as i have the error: kit $50 vs new pump $260, possibly better off just buying new pump, but fingers crossed



C1A20-64 (AF) Pressure increases too slow when filling reservoir

[loanrangie]

ok not ideal then. and i guess even if you had the outlet at the pump its still going through the desiccant, unless you tapped in between the pump and desiccant if possible.

anyway enough thread hijacking, i did order a desiccant/filter kit as i have the error: kit $50 vs new pump $260, possibly better off just buying new pump, but fingers crossed



C1A20-64 (AF) Pressure increases too slow when filling reservoirAny pump for $260 will be cheap junk, get the full rebuild kit and you'll get another 10 years out of it.

[haydent]

I did a desiccant and seal kit on my original hitachi only to find the dryer canister connectors where the problem and leaking... wish id sprayed with soapy water first.

Anyway have ordered a metal plate replacement but coming from overseas, but leaking isn bad now and car is not level so i ordered a cheapo oem off ebay as its in australia and i got it in a few days, just to keep as spare and to borrow the cover plate off it until the new metal one arrived....

Well it turns out there are at least 2 variants being sold, with the one I got, they have replaced the thinner tube appx 5mm diameter that plugs into the orange connector with 6mm connector and tubing.... one plus being that the connectors are screw in and so replaceable compared with stock being part of the lid.

Typically i didnt realise this until id swapped the plates over ... (this can be done with the pump still installed) , so now i have to swap the whole compressor over.... at least it will be drivable again.

So just note, if you want a closer match for spares get the one with the orange and blue connectors.

[DiscoJeffster]

Or buy from the recommended sellers on here where everyone has had success, else risk is you friend, or enemy

[haydent]

There's a non-return valve immediately downstream of the compressor assembly, so there's no need to de-pressurise the rest of the system if only the compressor assembly is being worked on.

technically its an electrovalve, so must be electronically opened to allow air in or out of the tank. Ill share some more overview data from the manual.


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