thefleshrocket

Last summer, I replaced the rear airbags on my wife's '11 GL450, which had around 70K on it at the time. (One side was leaking, so I did both.) I used Arnott bags from RockAuto.

A couple months back, I noticed that one side up front was intermittently sagging when parked, and not long after, the other side started doing the same thing. I ordered two new Arnott airbags, also from RockAuto. I finally got around to doing the project tonight, and it occurred to me that given the amount of work involved in getting the first strut out, maybe I should replace the struts as well as the springs.

Lo and behold, I found out that nowhere offers the struts by themselves--they just come with the airbags installed. So if a strut fails, I'll be throwing away a good airbag at the same time. I checked RockAuto and found that the strut assembly with the airbag is literally just $10 more than the airbag itself ($299 vs. $289). To top things off, I ordered the airbags 63 days ago, so well outside the standard return period. (I'll call RockAuto customer service tomorrow to see if they'll be nice, but I'm not counting on it.)

My question--how likely is it that the front struts, with 75K miles on them, are worn close to the point of requiring replacement? If these things regularly go 100K or more, then I might just suck it up and install the new airbags on the old struts, assuming RockAuto won't let me return them, but if I'm already on borrowed time, then I'll have to figure out something for replacing the whole assemblies.

And, why, oh why, would anyone sell airbags when you can't buy the struts separately, and when the whole strut and airbag assembly is barely more expensive than just the airbag?!

TX07GL450

Allright! While RockAuto is good and cheap, you might have to ditch it for another long term benefit. Start buying this stuff from FCPEuro. It might be a little expensive but you will get Free LIFE TIME REPLACEMENT. If not, then buy directly from Arnott, and you will get lifetime warranty (slightly better than FCPeuro).
My recommendation would be to replace both strut and bag as that is what I would do. At 75K, i think that they might go soon. Mine went at 80K miles and bags were good. I bought the whole thing and replaced myself about a year ago.

mefferso

70k-90k seems to be a common replacement mileage. My fronts were completely gone at 87k. It was so bad that it'd shimmy for about 5 seconds after hitting every moderate bump going down the interstate.

DennisG01

From what I've found out over the years, most always replace the strut/bag assembly - never just the bag. Because of that, I don't know if there's good data on how long the strut, itself, tends to last.

However, you're wrong that the bag is not available by itself. Arnott sells just the bag. You can't go by what cheap retailers offer - they only offer certain things. Go directly to Arnott.

thefleshrocket

I know the airbag is available separately--that's what I bought. The strut itself is what's not available by itself--if you buy a strut, it's coming with an airbag, no matter what. (At least as far as I can tell.)

thefleshrocket

I called Arnott and they said, sorry, they can't sell the remanufactured strut assembly without the airbag. I am waiting to hear back from RockAuto about returning the airbags, but am not terribly hopeful.

I went ahead and ordered AS2451 from RockAuto as their pricing is WAY cheaper than anywhere else on it--most other vendors want $450+. It's $450 each from RockAuto, but that includes a $150 core charge, so effectively they are $300 each. They do have the lifetime warranty, as well.

https://www.rockauto.com/en/moreinfo...1447293&jsn=16

Jason B

$78k miles here and rides like a dream

DennisG01

Oh, OK. I misunderstood what you said, above.

What does Arnott say about the RockAuto price and warranty?

thefleshrocket

I didn't ask Arnott--but according to RockAuto's link, the item does have a lifetime warranty. Presumably if I have any issues, I'll contact Arnott directly and provide my proof of purchase. If that falls through, I'll lean on RockAuto.

To be fair, I don't know how much longer we'll have this GL, so hopefully I won't have to test the warranty. The wife originally planned to keep it until it had about 100K on it (so another 2.5-3 years) but now she's making noises about getting a newer GL450.

thefleshrocket

Great news--RockAuto agreed to make an exception and allow a return on the airbags. I've spent a few grand with them over the last couple years, so presumably that's why they're being accommodating. The new strut assemblies have been ordered and should be here in a few days. Hopefully the reassembly goes smoothly.

DennisG01

Sounds good.

Replacement is pretty straight forward. The only mistake I made was I forgot to compress the spring/strut assembly which made getting it "out" difficult. I did think about compressing it... but not till AFTER I got it out! Typical.

thefleshrocket

Getting the old assembly out was definitely not easy--had to have a helper push down on a breaker bar (didn't have a pry bar) on the control arm to get enough clearance to get the bottom of the strut assembly over the CV joint. What's the trick for compressing the assembly?

DennisG01

I'm surprised the axle didn't pop out on you - it did on mine a few times.

Since I didn't actually remember to do the compression thing, I can't talk from actual experience - just from what seems like it would work. I think some electrical wire or possibly, a small ratchet strap, maybe even some not-too-stretchy rope should work. Once you have everything loose, you should be able to run the wire in a loop, around the strut assembly (over the top, between the studs, then down to the bottom), then compress the spring while it's still in the vehicle (I'm not sure if you'd be able to push it up by hand, but a jack under the lower control arm would work) and tighten the wire. That should keep it compressed enough to make it easier to remove.

alx

alx

Jason B

DennisG01

I've used that type of tool on coil overs, but how would you use that on an air spring/strut?

mefferso

Wish I had known about this when I did mine. Need to make this post a 'sticky'

TX07GL450

Nooooooo
This is for regular Mcpherson Coil/spring+strut assembly. If someone has ever changed both kind (coil and air struts) in different cars, one would know that this tool is not applicable for GL450 struts.

You simply push with a consistent force and air strut compresses slowly. Just use some strong wire to hold it in place.

a2j

Original struts lasted only for 80k miles or less. Front and back. Replacements from Arnott and Bilstein also didn't last more than 80k miles. Not too happy, but because 'lifetime warranty', I'm ok with it.
As far as airbags go, Arnott bags been very good. No issues for over 100k miles.

same

Assuming you are trying to be funny. Because it is.

SndsoftheSbrbs

Approximately 80,000 miles

My 2010 GL450 struts were replaced at 81,388 miles.

KrustyKustom

I replaced my 2011 GL350 front struts and bags at 106k, Rear bags only at 108k. Front struts seemed fine, tire wear has been great, good ride but leaking bag. At over 100k it is peace of mind to just replace the whole spring unit for another 100k hopefully. Rear shocks did not have any oil leakage and ride is great so will keep them for a bit longer. I do tow a travel trailer so my usage is perhaps a little heavier duty than passenger car duty.

Replaced Airmatic compressor and relay as well for preventative measures. When I originally bought the GL i was concerned with the Airmatic system but have learned to really like it. Great for towing, and consistent ride no matter how the vehicle is loaded. Really aside from the air springs the struts/shocks are expected to have the same lifespan as any steel spring vehicle.

conduit

What data is this based on? I've replaced the front and rears 3 times in 60k miles. Maybe driving 20mph on city streets is really hard on them though

backdoc4you

Conduit...I'm with you! I'm now about to re-order the forth Arnott front strut/airbag. I think the original MB ones lasted until about 75K miles and have now gone through 4 more Arnotts in the next 100K miles (about 25K...mostly smooth highway miles).

conduit

Oh no! I have been replacing mine with MB original parts at the dealership up to now, I was hoping switching to the Arnotts would be better! I guess they will at least be cheaper :/. The front right is exhibiting the dreaded "speed bump squeak / creak" but hasn't started to sag more than a half inch or so (just enough to look a little off kilter). I don't plan to replace it until it fails fully.