WISGL

The right front suspension leaks down on my 2008 GL 320. Usually, overnight, and it comes back up normally when I start the vehicle. In fact, it will usually "reset" back up to normal just when I open the driver's door, as the system normally does.

However, it doesn't always leak down. In fact, I let the vehicle sit for two weeks during a vacation, and upon my return, the vehicle was level in front, on both sides.

So, I can understand a leaking rubber component (the vehicle has just over 200,000 miles on it), but if that's the case, why doesn't it leak down consistently? I'm thinking it could be one of those valves I hear when the car levels itself? Something like that which could be erratic?

The vehicle is in excellent shape and I'll do what it takes to fix it, but I'd like to know if a simple valve or relay might be the problem before committing to more costly repairs. Any suggestions?
Thanks.

DennisG01

Tons of threads about this exact problem that you can find by searching. But the general idea is that it is quite possible for a bag to only leak at certain times because as the bag folds/unfolds on itself, it can squeeze the "hole" shut. Do the soapy water test. Try with the vehicle raised, too.

FYI, unless you've had the vehicle since new and can verify, it is highly unlikely that the bags are 200K old.

WISGL

Actually I have owned the vehicle since new, so it's original equipment up front. I'm just curious as to how the right side can leak down overnight, but then also stay level for two weeks.

DennisG01

That's pretty incredible that you have 200K miles on the original air bags. In fact, I think that's all but unheard of!

See my answer above. It could be something else, but what I mentioned is not uncommon.

WISGL

I had the rear air suspension replaced at 143,000 miles, but the front air bags have been good up to now. Thanks for your advice.

EWT

The front shocks do that in the early stages of failing. Mine have always started as a every 3 or 4 day thing, which turns into an every night thing, and eventually they start leaking badly enough that you can hear them hissing and they sink very quickly after the vehicle is shut off. Jacking the corner up that is sagging and fully extending the shock to check for leaks usually accelerates that process for some reason. 200K is amazing. You got a good set from the factory.

WISGL

Thanks, EWT. Sounds like it is time for new components, as you, the previous poster and the dealer are all saying the same thing. I just wanted to see if there is something simple we are overlooking. This GL hasn't been without its challenges, but overall, it's been a great vehicle, and I'm expecting many more good miles from it.

jonathankreb

My 2008 has only ~60k miles on it, and I recently replaced the front airbags, and then a month or so later had to do the rear. I experienced symptoms very much like you are describing as well. I used the after-market Arnot airbags and have been satisfied with their performance.

good luck!

EWT

If you're inclined, you can jack up the offending corner and spray the airbag with soapy water (I just use my simple green/water mixture in a sprayer that I usually use for cleaning) and look for bubbles to confirm it is really the shock that is leaking. However, doing so has twice dramatically increased the rate at which the bag leaks, I'm guessing because fully extending the strut tears the existing hole further. The last time I did it, the leak became so bad that the car went from sagging overnight to no longer being driveable - the compressor had to run continuously and couldn't bring the ride height up fully due to the rate the bag was leaking.

WISGL

Thanks, sounds like Arnot is the cost-effective way to go.

JohnAMG

Has anyone try the Blistein shocks? My GL550 front right with 160K Miles original shock is going bad and needs replacement soon.

John

Jeanreau

I was looking into this issue as well. Watched a ton of youtube videos. One Mechanic mentioned that the controller valve was causing the erratic behavior... as the rings can fail/unseat and reseat... which makes sense, because if the bag has a hole it should be consistent in its depletion... my 2 cents... I am having the same problem now at 140k miles and I just bought it less than a month ago... but I planned on it being an issue... Arnott does appear to be the way to go... and they have a lifetime warranty... but shops will charge you 3 hours to get it done and most are saying it only takes 1.5 hours... I may have to do it myself... ha

https://www.partsgeek.com/catalog/20...ion_valve.html

GLguy

Both times when it happened to me, I just replaced the air strut with MB part (~$700). It did take me more than 3h per front corner, especially the first time. The most difficult part was moving the strut over the half axle.

I used MB parts since they were available locally and I did not want to wait for aftermarket. Did the work myself.

Jeanreau

Did you replace the self locking bolts? I was reading the MB repair manual. There is a bulletin saying to clean out and replace the self locking bolts removed. If so, do you know the sizes and where did you buy them?

Thanks...

GLguy

I replaced on one side but not on the other. I got them from MB dealer.