chachd

I have a 2011 S550 with 140,000 miles. I'm pretty easy on it and it has been very dependable with very few issues. I'm concerned about the airmatic suspension longevity. Would it be best to replace it now or wait until I have issues? I intend to keep it as long as possible, hoping for 200,000+ miles, and I realize this is an expensive repair.

I appreciate any advice.

Arrie

Do it before it fails. 10 years is the mark so you are past it already, It is not the miles, it is the time for the rubber to go bad.

And it is not that awful expensive if you can do it yourself.

chachd

Thanks - Is there a thread in the forum with instructions?

Shadly1

I used a youtube video. There are quite a few. Even one from Arnott. Arnott is who you should buy airmatic parts from. They are great quality and have a lifetime warranty. Don't go with cheap Chinese. You'll end up doing it twice.

Struts, valve block and compressor are the wearable parts that should be replaced. Check the lines and reservoir with leak check spray. You can use bubble soap if you can't find any leak check spray but it's harder to spot leaks and harder to clean up.

Arrie

Buy Arnott thru FCPEuro. Like already mentioned they give life time warranty.

Parts about $1200 for front and $1100 for rear. You’ll have to pay $200 core on each that you get refunded after you return the old parts.

Arnott also has instructional videos and you can find others in U-tube. I have done front that is easy job. I have not done rear but I don’t think it is any harder.

Shadly1

That's a double lifetime warranty if you get them through FCP Euro. LOL . Rockauto sells the same Arnott stuff cheaper and without a core exchange. Same warranty.

chachd

Thanks for all of the information! I've checked the prices and installation and I believe I can do it myself.

I'm confused about the choice of compressors - FCP lists 4 options ranging in price from $299 to $419. Rock Auto lists 5 ranging in price from $277 to $375. Any recommendations on which one to choose?

Shadly1

All of those options weren't there a year ago. Bilstein is an OEM quality unit. It's going to be expensive and the warranty is going to be relatively low. The new Arnott unit is a good one and comes with a lifetime warranty no matter where you get it. I picked up that one from RockAuto a year ago. I'm a little surprised that FCP Euro is even offering a remanufactured Arnott unit. Anything from FCP Euro is going come with a lifetime warranty. AMK is the OEM manufacturer. Anything other than the options I just listed is going to be a rebuild and of questionable build quality. I've gotten burned on a rebuild.

Also, replace the relay and filter when you do the compressor. Those should always be done together.

Lotus GT

I'm replacing my front struts this weekend. I'll post back here if I encounter any tricky bits! Probably the most difficult bit with replacing the rear struts is getting all the trim out of the rear parcel shelf area if you have the Harman Kardon sub in there.

Lotus GT

Replaced both front struts today (still on axle stands though) - very straightforward job - no tricky bits!. If I wasn't having to deal with all the rust it would be finished.

Shadly1

Rust where? Top mount? Thats the only place i can think of where there is still steel and not aluminum.

Or are you doing some "while you're in there" rust fixes in the inner fender area?

Lotus GT

Yep - the steel areas on the inner wings. Most of the spot welds are beginning to show rust and lots of the area around the strut tops. Nothing serious (like it was at the back + petrol tank) but worth doing while I can get at it. Like the thread title - preventative maintenance .

I can recommend checking the petrol tank for anyone who lives in an area where they salt the roads in the winter - I was shocked at the state of it!

Lotus GT

Update - might be useful to original poster and others: My car has done 92k miles. Last summer I replaced the rear air struts (torn gaiters) and it made a huge difference to the ride of the car. Replacing the fronts this weekend has made an even bigger difference! The first thing I noticed is that there is now less body roll - this has been the feature of the car I've liked least - there is still body roll, of course, but it is controlled so much better now - the car doesn't "fall" into corners any more - corners a little flatter (not ABC flat!). As a consequence the steering has become more precise. The damping is much better, of course. I replaced the pump and filter, valve block and relay as well. The dampers are Mercedes exchange units.

If anyone is in doubt about replacing their Airmatic struts/dampers I can thoroughly recommend it.

chachd

Thanks to all for the help and information. I have several other questions on service I might perform while I have it torn apart.

!. Should the wheel bearings be replaced also?
2. Would it be a good idea to replace the rotors and brake pads?
3. Is there any other maintenance I should do while I have it apart?
4 Should I start with the front or back?

Since I'm not having any current problems I will most likely wait until the weather warms a bit - April or May.

Shadly1

You don't need wheel bearings unless yours are making noise, went dry, or leaking past the seals. An inspection under the dust cap wouldn't be a bad idea. If you do lube them, use the green grease.
You don't need rotors unless your brake pads are worn away. Sometimes replacing them are less expensive than turning them. You can also replace the rotors if you have warped or cracked them. In that case, you will probably replace the pads as well.
Not too many maintenance items under there except inspecting the rubber. Look for cracked, broken or missing bushings at the ends of your control arms. Also, check for loose ball joints.
Front and back are of equal difficulty. Just different processes to dismantle.

Take a look at your service intervals. It's a good opportunity to handle any recent ones that may have been overlooked.

Lotus GT

Remove the soundproofing under the floors (on the underside of the car) and check for rust on the bodywork - mine had some serious corrosion in several places. Also the brackets on the petrol tank that support the rear of the soundproofing had rotted off, leaving pinholes in the tank itself. The feed pipe to the tank was also rotting in places, as was the breather where the rubber section is connected.

The brake pipes are painted steel and begin to rust - (they are painted and then bent - the paint cracks at the bends and allows the pipes to rust) they are above the rear subframe and around the side of the petrol tank - again check for rust.

The aluminium heat-shields are held on with mild steel fasteners and again corrode around the fasteners - I replaced the ridiculously expensive Mercedes fasteners with large o/d BMW ones with large stainless steel washers on the inside to support the heat-shields where they had turned to dust.

The diff oil is never scheduled to be changed - unless it has already been done you could change it while you're under there (likewise the power steering fluid if it's not been done, but nothing to do with the suspension!!)

chachd

Thanks for the information. Brake pads and disks were replaced at 60k miles and although they aren't down to the wear sensors I suspect they will be due soon - 80k miles on them. Last service inspection mentioned the pads were getting thin and should be replaced next change.I'll check the other areas you've mentioned.Only other issue is that the rear headrests won't pop up.

Lotus GT

Don't you have to manually lift the headrests? They drop down at the touch of a button, but I'm not sure about up.

Arrie

I think in cars with electronically adjustable rear seats the head rest comes up automatically when you sit in the rear seat.

Shadly1

That's so you don't get Grey Poupon on your headrests

Honorio Lim

I been told that the brake pads and brake rotors are sets replaced together. That the rotors do not have enough allowance for refacing. There is a minimum rotor thickness. I also read factory info confirming this. So were those information not right?

Shadly1

You can turn them. You have about 2mm between nominal thickness and discard thickness. If the rotors are relatively new and you're replacing pads, it's worth measuring. If you need to pay shop rate to turn rotors, it's going to be cheaper to buy new rotors anyway.

The Thomas J

I had a real nightmare with ordering compressors the past year or so. I redid the entire suspension on my GL550. I bought the expensive compressor from Arnott through Rock Auto because it was an AMK and made in Germany. It was loud from day one and failed in 10 months. Arnott parts come with a lifetime warranty, which s great, but it's a PIA. My feeling is that my "new compressor" was a failed unit that was rebuilt and resold. The "second new" compressor has worked much better, and is quieter, but not nearly silent as the one in my S550. Long story short, whether you buy the cheap Chinese compressor, or the expensive made-in-Germany compressor they are all probably returned core units that were rebuilt with cheap Chinese parts.

The Thomas J

As long as they aren't metal on metal you could probably get away with it. The issue I see is that the rotors will warp over time and you will have to replace them anyway. A visual inspection will tell you what you need to know.

Chachd72

I worked for a company that machined oem rotors for GM and Ford and would say that both are correct although things have changed. In the 70's through about 2000 the rotors were typically heavy enough to be machined once. Manufacturers made them lighter in the name of weight savings so their thickness was reduced to the point that it is no longer recommended to have them refaced. Keep in mind that an auto brake shop would most likely not have the precision equipment to make an accurate cut, so you'd have to replace them anyway. Among the spec that we measured for quality was the thickness variation of the surface. For one manufacturer there was a very tight thickness variation that went into their top of the line cars. Rotors that were less precise went into their lower level models and ones that failed that spec were sold for aftermarket replacements! That was the state of the American auto industry in that period.