Recently bought this 2006 LR3. Been having issues with front suspension since purchase in that slow to raise and drops over time. PO stated right front strut was brand new and gave me a brand new left for install. I did the install. I also have rebuilt the front and center valve blocks and purchased a new Hitachi compressor. Have sprayed for air leaks and have found none. Front still drops slightly overnight. And front end slow to raise. I’m eliminating ride height sensors because it drops evenly overnight with the fuse pulled. Could the valve block be shot even with rebuild? Could there be a slight leak I can’t see in BOTH front struts? Any suggestions???
TIA

 

Yes, valve block can still be faulty. They can leak internally so don't give symptoms like bubbling.

 

Thanks for that....if they leak internally then where is the air going?? It has to escape somewhere.....


Quick update after another confirmation test overnight....front dropped a lot...rear also dropped but only ½" (both sides). Does this point to possibly all three valve blocks? And if replacing valve blocks, are these something that need to be purchased from a place like Atlantic British or Lucky 8($$)? Or are these parts something that can be gotten elsewhere for much less money?

Thanks

 

When you rebuilt the valve block, did you use ALL the o-rings? Did you happen to apply anything in the process to the o-rings before assembly? The valve blocks, when off, default to a closed state the the o-rings are sufficient to keep things sealed. Each side is separate unless the cross-link leak which is a path in the valve block that connects both sides and opens up at slow speeds and when rock crawling to give a smother ride and increase cross articulation. Then you have the feeder part of the block that lets air in or out from the gallery. The gallery is basically the lines from the front and rear to the compressor. The gallery is open to the compressor, always. And by design it leaks down because it does not need to hold pressure and it needs to leak out so the compressor, when starting, is not fighting 200psi to start up. This is also why you will hear a compressor "fart" right before it starts or stops, to dump the gallery air. The reservoir stores extra air to help in raising and has its own valve block at the center, just ahead of the compressor. It does NOT regular air to the front or rear, only the reservoir. Normally when you reach a selected height and the vehicle stops raising the compressor will still run for a while to refill the reservoir. The reservoir does not always have a full supply of air and when that happens you will notice the vehicles raises a lot slower. This is normal and okay. If you get vehicle raising slowly alert on the dash it means the reservoir was empty when you selected a height increase and it has to rely on the compressor along to raise everything. If this happens a lot, then the compressor may be underperforming or the reservoir has a leak.

As for dropping.... the engine, it is heavy. So if the front drops it does not mean you have a leak on both fronts. It could be one side but the other strut will compress also as it takes up the additional weight. You may need to really go to town with some soapy water again. Spray the valve block all over, its connections, etc. Soak it. They can leak right at the body seam itself. You also need to spray the top of the struts, both where the line connects and the center bushing at top middle - they can leak there. You may want to also try to spray up and under the aluminum shell to see if the airbag itself is cracked and leaking. If the bag is leaking you may have mixed overnight results, for example at normal height it may drop overnight but at off-road it might not. That usually means a strut has a leak in the bag and at off-road heigh the crack is sealed up better.

If you get new valve blocks, OEM are very, very much recommended as many people have had issues with aftermarket. But if you rebuild them correctly they generally last a long time. At over 230k miles mine are still original but I have rebuilt them a couple times. Also one BIG issue is the compressor dryer desiccant can contaminate the system. This causes a white powder to end up in the lines and get onto the valve block o-rings. That causes them to not seal well. If the compressor is old and the Hitachi style, I recommend rebuilding the dryer then waiting a couple weeks for stuff to blow through the system before doing the valve blocks. Since your compressor is new, you could try rebuilding the valve block again to at least see if there is fresh contamination on the o-rings.

 

OK, lots of good info in there...thank you!!

Yes, I used all of the O-rings and applied the little jelly substance that came with the O-ring kit to each O-ring. When doing my leak tests yesterday I also had the air tank out and connected spraying that entire thing with soapy water...no leaks. I did also douse the front valve block pretty good yesterday all over it and found no leaks. Today I notice when the compressor is running to build up gallery pressure, once it gets to 270 degrees it shuts down as normal, when it cools down enough to turn back on the gallery pressure has lost about 7-8psi from what it was when the compressor shut off. It does surpass that eventually but once it gets to overheat temp. and shuts off the gallery then loses that 7-8psi again while it's cooling down. Is this normal? Will the gallery pressure consistently drop or should it stay around 200? I also do understand that the engine is heavy, which could help to account for slower raising than the rear but I wouldn't think a heavy engine would cause overnight drop.

The overnight test was done at off-road height.... 24hr measurements LF-34 15/16 to 32 ⅞ RF 34 ¾ to 31 ½ LR 35 ⅝ to 36 RR 35 ⅝ to 35.

Tomorrow I will be doing more spray tests but I feel like I've covered a lot of ground with that soapy water. LOL. If I try and rebuild the valve block again, I assume you mean with a new O-ring kit? Or just open it up to see if it looks like there's fresh contamination?

 

Not sure why the o-ring kit came with any type of lubricant. Maybe for the solenoid shaft... but the o-rings MUST be dry and free of anything and everything. And nothing like brake fluid or like the likes can contact the o-rings too because they may swell. When you sprayed the tank, were you sure it was pressurized? Basically after spraying did you try to loosen the air line to it to make sure air came out? If it had a hole, it could have been empty. Gallery pressure will drop after the compressor stops and it should drop A LOT right before it kicks back in because it will intentionally vent (fart) just before it fire up again. It can not start with a pressurized gallery because gallery pressure goes right to the head of the piston. Motor is too small to fight a ton of pressure to get the compressor going. When running to fill the reservoir, it should reach over 200psi, probably around 230psi. At that point the system assumed the reservoir is full and closes the center valve block to the compressor and turns off the compressor.

With new orings you can reuse them. Not sure how you will clean them tho. Did the kit say to apply the stuff to the o-rings? If so, never heard of that and like I said they must remain dry.

 

Yes, the lubricant came with the kit and the video that I watched showed slightly lubricating all the O-rings prior to installing them. The kit came from 4x4 Air Seals.
https://4x4airseals.com/product/land...ing-repair-kit

Yes, the tank was pressurized. I removed it and reconnected it, started the engine and let the compressor get everything up to pressure. I did unscrew a bit the screw at the end of the air tank to confirm that it had pressure.
When the compressor stops the gallery pressure does immediately drop to around 50...it stays there until the compressor 'cools down'. When the compressor kicks back on the gallery pressure jumps up to about 7-8psi lower than it was before the compressor kicked off the previous cycle.

 

Well if there is any desiccant remains floating in the system it would cling to those seals even better if they have stuff on em. So that is my concern. I think you did good testing the reservoir.

 

understood and don't disagree. I'm going to be having a soap test party tomorrow and also opening that valve block back up tomorrow to check it out. Will post back any findings. But this is beginning to drive me a bit mad. I also found that my right rear height sensor seems to be bad as the voltage stays at 4.92 constantly. So I guess I'll be ordering a pair of rear height sensors.

 

Sensors can be replaced one at a time, no need for pairs if you do not want to.