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What's the typical lifespan of the rear shocks (I don't mean air spring/bag). I have 115k mi on a 2010 GL and I don't know if the previous owner ever changed the rear. I had to replace the front struts but rear height is OK.
For anyone that had bad shocks with air bags still good, what were the sign and symptoms? Should I proactively replace or just wait for signs of impending failure?
Rear shocks going out leads to a roaring noise coming from the afflicted wheel / side. You'll think a wheel bearing is going out. (It's not; the wheel bearings are tough). The tire will develop a cupped wear pattern.
What's the typical lifespan of the rear shocks (I don't mean air spring/bag). I have 115k mi on a 2010 GL and I don't know if the previous owner ever changed the rear. I had to replace the front struts but rear height is OK.
For anyone that had bad shocks with air bags still good, what were the sign and symptoms? Should I proactively replace or just wait for signs of impending failure?
Replaced my non-ads rear shocks and bags at 120k
Shocks were leaking and bouncy-obvious
Bags were leaking as well, also obvious
80-120k miles seems to be the window.
Air bag replacement can be done in 15 mins
Shocks take about 1-1.5 hrs a side as the interior wall panel has to come out to do it right.
Thanks for all the replies. I'll replace them then. I bought the parts (Arnott) but was debating whether to wait or do them now. I'm sure I can ascertain their condition once I take them out. I suppose if the air springs don't need replacing if they're not leaking yet.
One more question:
When I'm cruising at 40-60 mph the air compressor turns on (confirmed with DAS), sometimes every few miles and especially when coming to a stop. I hear the telltale air bleed puff sound when the compressor shuts off (like you hear after you park), but this happens while I'm driving. It reminds me of big trucks/rigs that give off such puffs from air suspension/brakes when in motion. I spoke with MB Service Advisor and he says that's normal with the mileage on my car (115k mi) and the compressor may be getting weak. The car doesn't lower when parked overnight and has new front struts.
Should the compressor really be coming on that often when driving?
Could a leak from elsewhere, like the valve body, cause this without necessarily affecting the height overnight?
Thanks for all the replies. I'll replace them then. I bought the parts (Arnott) but was debating whether to wait or do them now. I'm sure I can ascertain their condition once I take them out. I suppose if the air springs don't need replacing if they're not leaking yet.
One more question:
When I'm cruising at 40-60 mph the air compressor turns on (confirmed with DAS), sometimes every few miles and especially when coming to a stop. I hear the telltale air bleed puff sound when the compressor shuts off (like you hear after you park), but this happens while I'm driving. It reminds me of big trucks/rigs that give off such puffs from air suspension/brakes when in motion. I spoke with MB Service Advisor and he says that's normal with the mileage on my car (115k mi) and the compressor may be getting weak. The car doesn't lower when parked overnight and has new front struts.
Should the compressor really be coming on that often when driving?
Could a leak from elsewhere, like the valve body, cause this without necessarily affecting the height overnight?
No, a healthy compressor in a leak-free system should not be coming on that often. Go for a drive and measure the compressor run time during that drive, if you have Das. Should not be running the majority of the drive.
You can also test the compressor or valve blocks for leaks in Das. The compressor test limit is 16 bars within 40 seconds - if it takes more than a few seconds to build that pressure the compressor is weak. The limit is 40 secs and very generous so Das will often say the compressor is ok - but it will have to run all the time to make enough pressure to keep the air bags pressurized at around 7 and 9 bars, back and front. Your compressor sounds like it is ok per the standard, but may be failing.
Proper leakchecking will require getting eyes on and some leak finder spray. Don’t always trust Das to find leaks for you - they’re more indications of where to look.
Thanks. I'll check the ON time on a test drive. Any thoughts about the cheapo aftermarket compressors on eBay for about $130?
BTW: I've replaced the rear shocks. They were lower than the Airnot and showed sign of leak but didn't look completely shot. The front is one of easiest struts but I've replaced, but the rear were quite a piece of work to have to remove all the interior side panels to get to get to the top nuts.
Any thoughts about the cheapo aftermarket compressors on eBay for about $130?
If the compressor fails, the vehicle becomes undriveable. Maybe not immediately, but soon enough. Why would anyone go cheap on a mission critical part?
Go with Arnott. It's more expensive, but you get a lifetime warranty and supposedly it is an improved version.
Thanks. I'll check the ON time on a test drive. Any thoughts about the cheapo aftermarket compressors on eBay for about $130?
BTW: I've replaced the rear shocks. They were lower than the Airnot and showed sign of leak but didn't look completely shot. The front is one of easiest struts but I've replaced, but the rear were quite a piece of work to have to remove all the interior side panels to get to get to the top nuts.
Yes the rears are a piece of work.
To clarify my earlier post - check run time BEFORE and AFTER a timed drive. When you log into the Airmatic module using DAS it defeats the compressor's normal operation so it won't tell you what you need to know real-time.
The only thing you should stay logged into Airmatic for is to real-time read an airbag pressure value or level sensor value when (someone else is) driving - pressure drops will point towards a leak in that bag (or line), implausible or no-change in voltages will point to a stuck or invalid level sensor.
Why would anyone go cheap on a mission critical part?
I usually don't go too cheap on parts but someone here mentioned all the compressors are manufactured by two companies (Arnott and MK?). Besides, in just three weeks of owning it I've put in quite a bit into this truck. I don't mind fixer-upper but so far have replaced:
Intake manifold (broken actuator)
Front struts, filter/drier (both front wheels were at fender with compressor fuse popped)
Rear shocks (upon advise from this thread) - I see rear air springs in my future soon
Rear gate latch (often wouldn't open or close) - still wouldn't close sometimes with remote or red button
EZS/EIS module due to intermittent start (had to crack open and fix cold solder joint)
V-belt and squeaky idler pulleys
Steering angle sensor with "ESP/ABS/ABV Inoperative" error (had to crack open to clean optics and fix cold solder joint)
Investigated secondary air pump and rear AC control/valve issues - all seem to be mysteriously working now with no error so not sure why the errors showed up
Plus a few extras like spark plugs, air filters, multiple exterior bulbs, running board, engine oil (still have more fluids flush/exchange and mirror turn signal to do).
This is definitely more than I typically put in upfront for a used car, but thankfully it's only cost me parts since I can't pay myself for labor.
If there really is a difference in compressor quality and not same part with multiple distributors/markups then I'll go with Arnott.
To clarify my earlier post - check run time BEFORE and AFTER a timed drive.
Thanks, will do. Earlier I noticed all corners were steady at 10 bar including the central reservoir. When the compressor turns on while driving it the central reservoir that I see build up pressure. The air bags remain steady. The compressor currently has 1489131 seconds (over 400 hrs) on it. It seems quite high, but I don't know what's normal for a 115k mi AIRmatic.
I usually don't go too cheap on parts but someone here mentioned all the compressors are manufactured by two companies (Arnott and MK?). Besides, in just three weeks of owning it I've put in quite a bit into this truck. I don't mind fixer-upper but so far have replaced:
Intake manifold (broken actuator)
Front struts, filter/drier (both front wheels were at fender with compressor fuse popped)
Rear shocks (upon advise from this thread) - I see rear air springs in my future soon
Rear gate latch (often wouldn't open or close) - still wouldn't close sometimes with remote or red button
EZS/EIS module due to intermittent start (had to crack open and fix cold solder joint)
V-belt and squeaky idler pulleys
Steering angle sensor with "ESP/ABS/ABV Inoperative" error (had to crack open to clean optics and fix cold solder joint)
Investigated secondary air pump and rear AC control/valve issues - all seem to be mysteriously working now with no error so not sure why the errors showed up
Plus a few extras like spark plugs, air filters, multiple exterior bulbs, running board, engine oil (still have more fluids flush/exchange and mirror turn signal to do).
This is definitely more than I typically put in upfront for a used car, but thankfully it's only cost me parts since I can't pay myself for labor.
If there really is a difference in compressor quality and not same part with multiple distributors/markups then I'll go with Arnott.
Oof that's quite a list. At least my own grief has been spread out over nine years now.
I certainly have the impression that Arnott does their own manufacturing. I replaced my pump before it failed; the replacement Arnott pump was quieter, though that may simply have been imminent failure on the original. You could ask them who does their manufacturing.
I bet there are rebuilders out there, who range from dogsit to great.
Regarding your SAS: where was the cold solder joint? I have a replacement unit sitting on my shelf, but my failure is so intermittent I don't get around to replacing it.
OK, thanks. I remember some of the reviews of a cheap one saying it's loud. I'll go with Arnott.
Originally Posted by eric_in_sd
Regarding your SAS: where was the cold solder joint?
I don't have pix of the connector (I thought I had taken a couple). They were two of the connectors on the circuit board. They are through-hole connectors that looked like they had just been pressed into the holes without any soldering. I also found this bracket broken (marked with blue paint). This made the whole column wobble up and down which I think created an intermittent connection to the black connector in the picture. It looked like someone had mocked around with it before me and must have tried to pull of the shroud without removing the screw that attaches the shroud to this bracket.
My first MB - I like the ride so far but not impressed with some of the quality of workmanship.
I don't have pix of the connector (I thought I had taken a couple). They were two of the connectors on the circuit board. They are through-hole connectors that looked like they had just been pressed into the holes without any soldering. I also found this bracket broken (marked with blue paint). This made the whole column wobble up and down which I think created an intermittent connection to the black connector in the picture. It looked like someone had mocked around with it before me and must have tried to pull of the shroud without removing the screw that attaches the shroud to this bracket.
My first MB - I like the ride so far but not impressed with some of the quality of workmanship.
Thank you for the picture and description. I'll take a look. It can't be electronic like this if it's long term intermittent. Probably not, at least.
The GL is funny. I hated it, just hated it when stuff started to go wrong at 60K miles. I got the dealership receipts for the first 30K and it was an insane stack of paper. But you get the bugs worked out, and it's oddly endearing. Forum user alx put it perfectly: That truck ages well. We get guys coming on here all the time saying what a hunk of junk, I'm buying xyz. That's fine; truth be told, I'd rather have a Ford, maybe an Expedition or F150, but for now I've got no compelling reason to ditch it and pay the ~$5,000 in sales tax to buy something else. And I like driving it, dammit. I've put 130k miles on it, and it still drives great at 160k.
My big turning point for sticking with it was when I went off-roading. It's a damn solid 4x4.
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