Air Suspension Leak Down after Sitting 2 Weeks
- Thread starter WalleyeMikeIII
- Start date
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Since failure isn't always immediate detection on an air suspension system. Finding leaks in a system that spans across the entire wheelbase is not the simplest and quickest of tasks.
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WalleyeMikeIII
Full Access Member
Right, well, we do know it is in the rear.
We also know that the compressor and the reservoirs hold pressure (because the system can raise the vehicle on key on, without the aid of the compressor running).
So, at that point the possible leak points are, I think:
Air springs themselves
Fittings on the output side of the control valves.
Hoses from Control Valve Output to air springs.
in 99.999999% of situations it's either a bladder leaking, or the relief valve on the pump.
the lines could be from the 1970's and won't leak....... the design has been the same since then
soap and water will tell you which is the case
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WalleyeMikeIII
Full Access Member
You may be referring to the older "real leveling models" vs this four corner air suspension in the T1's. This design is different than the stuff that was on the previous models...
The previous version had the shock and the air bladder integrated.
This version has the "Air Spring" separate from the shock.
See P/N 85521600 and P/N 85619254
The Older stuff had rear leveling shocks/bladders integrated, here is the 2013 Example.
P/N 23487280
i see, different design, same concept...
the most likely place to "find" a leak is the bladders, or pump intake or relief valve (circled in 2nd pictured), the manifold is not likely to be bad but who knows with GM cheaping out anymore. just spray everything with soap & water mix and watch for bubbles
3 times I took it in and told them it was leaking they kept reprograming modules. Now they acknowledge its a leak not programing. Told me nothing wrong it was within spec also. Also said 'no code no problem".
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WalleyeMikeIII
Full Access Member
I had success by:
1) Photographing the vehicle in my garage, parking it, letting it sit, and measuring the drop at time intervals, and recording those w/ photos and a tape measure.
2) Assembling this info (including the photos) into a document and handing it to the service people at the dealer.
3) Using the info the dealer provided to me to identify the leakdown specification (2mm/day)
4) Offering/Telling the dealer to keep my vehicle in their climate controlled facility for a few days and measure it daily (while they provided me a loaner). They definitely agreed it leaks all the way down over a weekend, now.
I believe #4 is what broke it all loose. They are now replacing the air springs and seals that go with them...if it continues to sag, they will have to own finding the problem.
Now, fortunately, I was in position to be happy w/ their loaner for the few days it took for them to replicate the issue -- you may not be so lucky...I don't understand why the service people are so reluctant to actually believe the customer...but on the other hand, I also know there are a lot of people out there who are not well versed in how their vehicles work..and thus I cannot imagine the crazy "customer states" things they see on a daily basis.
