air suspension problems

Eric K

Observer
Someone commented a while back how to figure out which wheel has the air suspension leak. Something about pulling fuses for leveling and that will allow you eliminate options? I did not need the info at the time, but now I do. Anybody know this handy trick and can give me the full details?
 

John R

Active member
Have you tried spraying everything with soap water? That might also help and it’s dirt easy and cheap
 

Eric K

Observer
I found this comment by Benjaminjaninja or something like that and thought I should repost it as it seems pretty helpful.


Here's the basics to find a leak:
-Raise the suspension to off-road height.
-Pull Fuse 3 in the engine compartment, this will disable the suspension ECU which will prevent the computer from waking up and self-leveling over night.
-Measure all four corners of the truck with a measuring tape from the center of the wheel to the top of the fender liner.
-Depending on how slow your leak is it may take an hour or 8 or 10 to see a change. Measure all 4 corners again.
-Since the computer never self-leveled the car you can now determine these scenarios:
1: Front two corners lowered while rear stayed same or nearly same---Front Valve Block issue (Or 2 air struts are failing at the same time although unlikely)
2: Rear two corners lowered whole front stayed same or nearly same---Rear Valve Block issue (Or 2 air struts are failing at the same time although unlikely)
3: All 4 corners lowered---Front and Rear valve block issue (Or all 4 air struts are failing at the same time although unlikely)
4: One or multiple corners lowered significantly more than the others---One air strut is leaking at that corner, the bag or at the connector

If you need to change a valve block, consider buying a seal refresh kit ~$35 I think and replace the seals first. There are several other post here that detail that procedure. What happens often is that the desiccant dryer elements in the compressor break down to a fine dust over the years and gets distributed through the system to the different seals. That then breaks them down and causes leaks. If you replace the seals its a good idea to replace the dryer elements at the same time to prevent this happening again to your new seals. Those kits are on ebay, but make sure you know which brand of air compressor you have. Hitachi or AMK.
 

Howski

Well-known member
I would add that if it falls under one of the above valve block scenarios and a rebuild does not fix it, do not rule out the valve block. The block can be leaking internally and back to the compressor. This happened on mine and I’ve read of several similar accounts
 

Carson G

Well-known member
If you rebuild the valve block you have to replace the voss connectors they’re one time use only.
 

Eric K

Observer
OK, so after 24 hours all 4 tires went down around .5 inches. So I guess front and rear valve block issues?
 

douglastic

Member
Before you clean out or rebuild/replace the valve blocks, I would strongly suggest that you replace your compressor desiccant if you haven't already. There are rebuild kits out there, some even include a metal end cap to eliminate the common crack that develops between the fittings. Mine had the crack too (easily see w/ soap and water)

The old desiccant breaks down and turns to dust - this dust travels through the tubes into the valve blocks causing leaks.
Cleaning the valve block helps for a time, but you should eliminate the source if the problem or you will have to do this again soon.

Waiting a few weeks after compressor refresh should be enough - then tackle the blocks.
Mine have been holding quite well for almost 10k miles after doing this process.
 

shawnpalmer

New member
I was told to disconnect the battery which shuts the whole system down.
After 3 days of battery disconnect on LR3
Drivers Front +.25 in
Passenger Front -1 in
Drivers Rear -1.25 in
Passenger Rear -2.75 in

What do you think my suspension issue is?
 

John R

Active member
I was told to disconnect the battery which shuts the whole system down.
After 3 days of battery disconnect on LR3
Drivers Front +.25 in
Passenger Front -1 in
Drivers Rear -1.25 in
Passenger Rear -2.75 in

What do you think my suspension issue is?

It still sounds like Valve block issues. If it were mine I’d do the filter and both valve blocks. I’d spray all the connectors with soap water and if I still had issues of lastly rebuild the compressor.
 

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