Help diagnose LR3 Air Compressor?

[GregInMI]

I'm hoping someone can help me diagnose the air suspension compressor problem I am experiencing.

The truck is a 2006 LR3 HSE V8 with 150k miles. It developed the suspension fault, yellow light, raising too slow, and eventually settled at the bottom of the suspension.

Wanting to get the truck back on the road quickly, I swapped the compressor for a low buck chinese knock off by Dorman.

The new compressor raised the car, but responded slowly enough that I still get the fault for slow response. Before the fault shuts off the compressor I can hear it slowing down progressively until it basically stalls and the fault is generated.

I looked at the gallery pressure data with my IID tool and see about 1050kpa, which seems on the low end of the operating range.

So my question is, do I go buy another GOOD compressor because the one I have is garbage, or is there a valve in the system that could be hung up and I am pumping against a dead headed pressure system which is causing the slow response and the compressor to stall?

I appreciate any help someone can offer, I don't want to just change parts.

Thanks,

Greg

 

[sunrisehiker]

It sounds like you are going against a half open or closed cross articulation cylinder pin in one of the Valve blocks, maybe all of them and there are three.
At this mileage i would change all of them as it is time anyway.They are probably clogged up with tiny particles from disintegrated silica desiccant from previous compressor.I know it helped me.Could also be a faulty pressure sensor, that site on center valve block. I am over 183 000 miles now , but last year replaced all three valves and it helped me tremendously .I can leave my LR3 for two weeks standing and it does not drop even a 1/4 on an inch now.
On another note though, I hear across the boards that Dorman is crap and can't cope with pressure needed for rising our suspension .Have you tried to rebuild your old Hitachi compressor yet ?
What are you reading as Fault codes on diagnostic tool ?

 

[GregInMI]

Thanks Sunrise, I appreciate the help.

I'm suspecting the Dorman compressor is a big part of the problem, lesson learned...again!

With the compressor out the center valve block and pressure sensor are easily accessible so I'll plan to change that too. I think that will get me back in business, and on to some new rear control arms too.

I don't lose significant ride height when partied for a day or two.

I put a rebuild kit in my old hitachi last night but it isn't building pressure at all and I hear an air leak that sounds like it is within the compressor. I suspect the failure mode is a stuck valve in the compressor because the cylinder and piston wasn't too bad and the desiccant and filters looked better than I suspected. The Dorman builds some pressure, but not enough and then stalls.

The only suspension fault code I get is the algorithm based "responding too slowly" that corresponds with the yellow suspension light and the "normal height only" message.

Thanks again, I appreciate the second opinion.

Greg

 

[sunrisehiker]

You can get a new springs and O rings for exhaust valves and such, you can also rebuild piston sleeve, but if the piston itself broke, like it was in my case, you will have a hard time to source a ew one.
Which rear control arms you plan to change ? Upper or lower ?

 

[GregInMI]

I was planning to dig into the exhaust valve on the hitachi compressor tonight. I have already replaced the piston ring, glide sleeve and associated o rings and replaced the desiccant and filters. It runs well after the rebuild but the exhaust valve seems to be leaking.

I'm thinking of replacing both upper and lower control arms in the back. They are knocking like a tool box back there. The ball joints and toe links were replaced at about 110k but the arms/bushings were still ok then. Front lower arms and tie rods were done at about 80k.

Thanks again.

Greg

 

[sunrisehiker]

Yeh...I did the fronts myself on the driveway alone with air struts and tie rods but the rears are tougher then expected.You can replace rear lowers without disconnecting brake lines.it is just a matter of carefully cutting into brake line brackets that sit on the lower arms in the way that you can reattach brake lines back, but the uppers require lifting a rear body of the chassis just to get a new bolts in. Not to high, but just enough to slide a new bolts into those pesky brackets so it is a job regardless.

 

[GregInMI]

Thanks for the warning on the rear arms. I was thinking of wimping out and using an independent mechanic here in the Detroit area for the rear end rebuild. It needs to end with an alignment anyway so it will be going to a shop for that.

150k miles is bringing on some real workload here. Two weeks ago I did the thermostat housing. I'm planning on keeping this one for a while, it has been my wife's daily driver for eight years but we are getting her into a new rover. My Daughter turns 16 in May, so the LR3 will hang on as dad's toy and daughter's occasional ride as we move into the new driver stage.

Thanks again,

Greg

 

[GregInMI]

Closing the loop on the Dorman compressor

Just closing the loop on the question I asked a while ago about diagnosing a bad compressor.

It turns out that the Dorman replacement compressor is just incapable of reaching the pressure that the LR3 system wants. It could only make 1250 kpa and took a while to get there. I replaced it with a Hitachi compressor and it had no issues building pressure to 1600+kpa quickly. No more yellow suspension fault!

Credit here to Rock Auto, where I purchased both compressors. They are taking the Dorman back and crediting me for the cost. It was longer than their return policy but they are covering it anyway.

Lesson learned, stay away from Chinese knock off parts!

Greg

 

[sunrisehiker]

Good news !
Over the last 10 years of owning LR3 I realized , that it pays off to buy a Genuine parts, especially crucial ones.Good luck !

 

[zelatore]

Yeh...I did the fronts myself on the driveway alone with air struts and tie rods but the rears are tougher then expected.You can replace rear lowers without disconnecting brake lines.it is just a matter of carefully cutting into brake line brackets that sit on the lower arms in the way that you can reattach brake lines back, but the uppers require lifting a rear body of the chassis just to get a new bolts in. Not to high, but just enough to slide a new bolts into those pesky brackets so it is a job regardless.

Wait...you're saying you had to lift the body to remove the rear upper control arms? I've had mine off w/o having to do this. Or did I misunderstand you?

 

[unseenone]

Wow.... no you don't have to lift the body off at all. Having a LIFT certainly will help a lot.

Reference points, there is a kit on Amazon which includes more than the factory kit, the guys mentioned here.
Here are the springs and bits LR part numbers in case anyone needs them. (not as complete as the kit I mentioned above).

LR020590 KIT - COMPRESSOR o-ring, rubber flap, spring 1 target price 8 ish
JPO500010 KIT - COMPRESSOR all the above, plus bolts, large spring, more seals, etc. 1 Target price 25 ish

 

[GregInMI]

Thanks for the info everyone.

On rebuilding my old Hitachi compressor, once I got into the compressor further I found significant corrosion in most of the aluminum parts. After 10 years here in Michigan (where it has been noted that even the trees rust) it just had to go.

Greg

 

[sunrisehiker]

Wait...you're saying you had to lift the body to remove the rear upper control arms? I've had mine off w/o having to do this. Or did I misunderstand you?

No, I said I needed to lift the rear up loosening four body mounts in order to slide new bolts for rear upper arms.There was no room to install them bolts otherwise.

 

[zelatore]

No, I said I needed to lift the rear up loosening four body mounts in order to slide new bolts for rear upper arms.There was no room to install them bolts otherwise.

Odd. I didn't need to fuss with body mounts at all to do my rear control arms. In fact, I did a field replacement of the driver's side upper rear in Sedona last year at the WNLRR when I broke the fwd eye. Pretty straight-forward.

 

[unseenone]

Probably lifted it from somewhere else.. Nice pictures though.. Loving it. I would love to hear more of an explanation of what we see pictured, and the apparent reason you went with different arms, are you suspecting the polybushes? What is the one you have there (new one).. Not to side track-- or perhaps start a discussion.