air suspension fun and games, LR3

[zelatore]

I spent last week on the trail in the Sierras and toward the end of the week noticed my EAS compressor running too often and for too long. The truck doesn't settle over night, plus the airbags are less than a year old, so I don't suspect a strut. My thinking was that I may have a leak at the compressor, tank, or distribution block.
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Today I dropped the slider and started spraying soapy water all around looking for bubbles. Of course, nothing is to be seen. In fact, the system seems to be perfectly happy - not running the compressor any more than to be expected with my assorted ups and downs. Hmmmm....
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As part of my checking for larger tire fitments (more on that later this fall) I used the GAP tool to dump all the air and put it on the bumpstops. This drives the wheel sensors out of range because I'm using Johnson Rods. Not a problem, I can use the GAP tool to manually pump it back up into range. When I selected 'raise all' and started inflating, the rear came up quickly but the front barely moved. I switched to 'raise front' only and it was very slow to inflate. Eventually I got it high enough to put everything back to normal but now I started paying attention to how fast the truck raises front/rear and noticed the rear always comes up much faster than the front.
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The question now before us is this: Normal or defective? It gets to the proper height, it just takes longer for the front to get there. Some of you other LR3/4/RRS guys, can you go out and run your trucks down to access then back up to off-road and tell me if the front moves up much slower than the rear?
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My thinking is I may have an issue with either the compressor or front axle Valve blocks. I don't know this, but perhaps I have some debris that is partially blocking one, or some other issue. This could possibly explain a slowly raising front, though I'm not sure how it would explain the compressor running to much/often while on the trail. If they were cheaper I'd just replace them, but at approx. $150/ea I don't want to just throw money away.
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Somebody go out there and lower/lift their rig and get back to me and we'll move forward from there.
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Thanks!

 

[Ray_G]

Before I switched to coils I noticed my rear lifting faster than my front, not dramatically so as it sounds like in your case but it was noticeable. Unscientific observation of course, but at least another item for the data pool.

 

[Colin Hughes]

Will have to try it on the LR3 but my P38 when up I. The back first, then the front followed.

 

[NickH]

I'm almost certain my lr3 rear raises first. It's not enough for me to even worry about it. It's not like it's a single bag or anything. My bags are also new.

 

[unseenone]

The front does lag a little. Probably two reasons for that, the bulk of the weight is there, and it is the farthest from the compressor/tank.

While you are checking for leaks, spray the front of the air tank, there is a fitting there that can leak. If you have deflated your air springs, and tank, it would be considered normal to get an error when you pump it back up, until the system has been fully recharged. When my air compressor started gradually running more and more, one error message popped up occasionally, "too many transitions" It turned out to be a bad air bag, which did not manifest itself until off roading in extended mode. So the leak ended up being in the air bag, which was an extremely slow leak, unless the leak was exposed when the air strut was fully extended.

I hope this helps a little.

 

[zelatore]

Seems to be pretty normal. Some newer rigs seem to lift a bit more evenly, but still slower in the front. Perhaps part of what I was noticing was that I was unloaded and I normally have my gear in the back, so between coming from a complete bumpstop dump and being lighter in the rear than usual it was probably exaggerated.
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Still don't know why the compressor runs as often/much as it does. As mentioned, it's more pronounced when on the trail but I still have it run after pretty much every start-up even when just in a parking lot. No signs of the truck settling overnight, and no signs of leaks around the tank or compressor.
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As a data point, the struts are new this year and the compressor was done last year. I haven't had any errors when it runs, but it was running a lot more than normal. Perhaps I'll put it in off-road tonight and check the gallery pressure with the GAP tool then check it again in the morning before starting to see where it is.

 

[A.J.M]

Mine rises up faster at the rear than the front as well.

I've changed the front valve black as the front was sinking overnight while the rear stayed up.
My compressor is getting changed this month to the AMK as it's on it's last legs, faults out when driving normally.

Did you go Hitachi or AMK when you changed?

 

[Jwestpro]

Still don't know why the compressor runs as often/much as it does. .

My AMK runs frequently but not for very long. It's as if it wants to adjust tiny amounts but more often.

 

[Jwestpro]

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As part of my checking for larger tire fitments (more on that later this fall) I used the GAP tool to dump all the air and put it on the bumpstops. This drives the wheel sensors out of range because I'm using Johnson Rods. Not a problem, I can use the GAP tool to manually pump it back up into range. When I selected 'raise all' and started inflating, the rear came up quickly but the front barely moved. I switched to 'raise front' only and it was very slow to inflate. Eventually I got it high enough to put everything back to normal but now I started paying attention to how fast the truck raises front/rear and noticed the rear always comes up much faster than the front.
.

The question now before us is this: Normal or defective? It gets to the proper height, it just takes longer for the front to get there. Some of you other LR3/4/RRS guys, can you go out and run your trucks down to access then back up to off-road and tell me if the front moves up much slower than the rear?
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Thanks!

The rear always raises first/faster. I have always thought this is because the rear differential is the lowest point and thus a higher priority to raise sooner but it could also be a simpler reason.

You really need to ditch those stupid shortened rods for sake of the Rover Gods. Just get the LLAMS interface and quite screwing around!

I drop mine down whenever I'm loading the root tent or the rack I mount it on or for stabilizing when camping. I lower it so far the rear tires actually tuck up higher than the rear fender flares. The front is even further. It's so low the top of the pivot bolt on the rack mounted Hannibal awning at the rear is just under 81" ! The Hannibal rack is sitting on Yakima cross bars, the rear awning mounts to the rack edge and sits up higher by a few inches. The pivot bolt for the awning arms is the highest point but will still fit under a standard height home garage easily I think it will go under 80" if I'd rolled forward and then back again to let the wheels splay out/relax the camber after the lowering.

The AMK runs for just a sec pretty much upon every morning start up but does not come on constantly while cruising for hours. I'd know because of the sliders and the bit louder sound they cause.

 

[dsm02c]

I think we all obsess over the air suspension, I had a high altitude trip recently and thought it was the compressor running when it was really the exhaust damper rubbing on my transfer case skid. (Finally put that to bed this afternoon)

That said I recently pulled the fuse to disable the auto leveling but still was hearing a high pitched noise while the truck had power (disconnecting the battery = noise stopped), I have tracked it down to the compressor or resivoir valve and will attempt a repair this weekend. When you look at the 250 PSI to run the truck up to regular off-road height I am not surprised my old hitachi runs frequently...

What PSI (gallery pressure while lifting) do you guys see with Rods in off road height?

 

[zelatore]

I don't have my notes in front of me but I want to say the kick-out is around 1750 KPa (sorry, my GAP tool only reads in KPa). The full lift is reached before that, but the compressor continues to run to (I assume) replenish the reservoir. Once it shuts off the galley pressure drops back to around 220 KPa.
-just did a quick google search for the conversion and it looks like about the same pressure you're seeing; around 250 psi when lifting.
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The rods should have no bearing on the pressure needed to lift the truck. It would still lift at the same pressure, just need more volume to hold it at the higher point. However I do have a lot of weight in my rig in the form of armor and gear and that would mean more pressure required.
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I've also just ordered the spacer kit from Lucky8 and will be installing that later this year in preparation for a bigger tire. I told myself I wouldn't do it until the winter, but I'm starting to get the itch to have it before the WNLRR in Sedona as well as our own NorCal Annual event. Then again, there aren't many free weekends between then and now.
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JWest - you might just convince me to go the LLAMS route eventually. Of course we're trying to fund a new shop build on the 'ol plantation so cash isn't flowing as freely as before.

 

[Jwestpro]

I've also just ordered the spacer kit from Lucky8 and will be installing that later this year in preparation for a bigger tire. I told myself I wouldn't do it until the winter, but I'm starting to get the itch to have it before the WNLRR in Sedona as well as our own NorCal Annual event. Then again, there aren't many free weekends between then and now.
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JWest - you might just convince me to go the LLAMS route eventually. Of course we're trying to fund a new shop build on the 'ol plantation so cash isn't flowing as freely as before.

Wheel spacers? What tire? I don't think they are really needed for even a 275/65x18 but then again I never have tried the new BFG ko2 without the spacer. They could rub the UCA at full strut extension .

 

[zelatore]

Not wheel spacers but strut spacers. The idea is to basically add a 2 in block to the top of the strut. This can result in over extending the CVs, so there are included limit straps. The spacers themselves don't cause any lift but if you run shorter rods they would result in you having the strut in its 'natural' range. The primary Benicia is that if you are dropped to the bumps tops by a failure you are still 2" higher than stock and should have no problems rolling even on a larger tire.

There's a thread elsewhere discussing them.

Oh, I do have some .75" wheel spacers coming but that's more of an experiment than anything. Not totally needed but if I can run them I would like the added track if possible since running lifted comes with a slight narrowing of the track anyway.

 

[zelatore]

One other note. The current tires are 275/65-18s on stock wheels and you are correct there is no need for spacers though the clearance at the front upper ball joint is very tight. The next tires will be 275/70s, which will be a full 33" assuming whatever I go with measures out true to spec.

 

[Jwestpro]

One other note. The current tires are 275/65-18s on stock wheels and you are correct there is no need for spacers though the clearance at the front upper ball joint is very tight. The next tires will be 275/70s, which will be a full 33" assuming whatever I go with measures out true to spec.

I will be interested in seeing how badly a true 33" grinds into the slider or trim between tire and lower front door of the body. I am pretty sure that it will also be almost actually touching at the rear mudguard.

I think 265/70x18 is the real ideal size but I also want to push the limit by trying a 305/60x18 that is 32.6" diameter and 12.2 section.