bmwm750

Of course they wear out- nothing that's mechanical in nature lasts forever. The more the thing runs, the faster it'll wear out- just like anything else. If you want to make sure it runs a lot, spring a leak in the system somewhere, and ignore it. Then it'll wear out in short order.

Yes, the compressors can be overhauled.

It sounds like you have a failed/ failing pump, and possibly a bad valve block. Likely not a leaking strut, since as you say, the car will sit level over time.

dvs_dave

Park the car up with jacking mode (disables auto leveling) enabled over night. That will tell you if you have a leak or not and where it is based on which corner or end sinks.

mcs

Yeah I have done that, and the car stayed level. It levels fine in Comfort and Auto and Dynamic, it takes forever to get into lift.

The ride is harsher than it used to be, The car has Sports Air so all the heights except lift are the same.

I think its just a worn compressor. I will simply replace the piston ring, and a seal and see how that goes.

If it goes well, for $30 the rebuild kit costs, I would probably redo it every 1-2 years as a preventative.

Mike

Petahs

I just installed the rebuild kit on a friends car took about 2 hours. It's fairly simple once you get the wheel liner off. 3 10mm bolts hold it on the car. Once it is off follow these Instructions

Mister Bally

Or disassemble the motor and epoxy/ JB Weld the loose magnet back in place. Then add glue to the magnet that has not yet failed.

05SilverA8

If the compressor has "melted down" meaning it has kept running until the motor burns out it is not worth rebuilding. A new compressor is about $500. If the compressor is "weak" it may be worth rebuilding.

aTOMic

Link to the original, well-engineered rebuild kit: BagpipingAndy

And may I add that the lines have tiny, fragile ferrules which, if I had to do a valve block R&R, I'd be sure to have spares... or at least be ready to note how they fit and catch any which fall out of the nut when you d/c the air lines (the ferrules start as one piece but have a segmented construction which is prone to break if flexed at all. They still work in two pieces, but you might want some kind of magnifying safety glasses cause they're awfully small and fiddly...)

Doesn't this failure mode create a certain rattling/clacking sound? Has he mentioned that (forgive me if so).

Re the G290 temp sensor and its reporting "implausible" (love that one) signals and over-temp shut offs, you can disconnect it and the module won't even set a DTC! Well how does it function, you ask? There's a built-in algorithm to cycle the pump based on ambient temp, run time, and moon phase. On mine, the wire (attached to the car, naturally) was broken inside the connector strain relief (connector being on the wire 6" or so from the pump). You should check that wire and connector carefully. The unbelievable thing is the wire was about 22ga (like earbud-wire size) and, about four-conductor! The copper was almost brittle! It appears thick because of its insulation.

Link to my adventure, FWIW, and compressor autopsy so you can see what's inside...
and a discount code from Arnott, not sure if it's valid anymore.

Re hissing, there's supposed to be a filter (located at the top of the wheel well after you get the liner off) on the clear in/out line to the compressor; on mine it had detached, and the thing sounded like it had air brakes. Pretty sure it's pictured in my big post; if not it's just like a mower fuel filter about 5X5cm (so relatively large); in fact I googled the # on it and it was a small engine fuel filter. Pretty sure it was original to the car, though.

Lastly, I think you said replaced it already, but new (stupidly located) compressor relay must accompany new compressor, and while you're in there do the $20 brake light switch - save many hard-to-diagnose headaches later on (and they fail a lot). Be aware the switch's plunger self-adjusts and you must not depress the plunger before you install it (and then the brake pedal arm will press it in and set it) because it cannot be undone. (ask me how I know).

-Tom

Mister Bally

Sometimes just a slower motor RPM and low air output as the armature is dragging on the loose magnet.

Sometimes an unusual noise.

mcs

Some developments;

I found the car's coding was 0011310 instead of the 0015510. This meant the car was 20mm lower than the normal sports height at the front and 10mm lower at the rear. (or 40 and 30mm lower than the normal non sports air ride heights)

I have changed it back to 0015510 as the ride was terrible and I don't much care for looks over my own comfort. (If it is too high I will lower it to 0013310 later)

However it seems that the front left strut makes a hissing noise independent of the valve air release thing. The code also added an air leak code to the G291 sensor code.

I suspect I need a new front left strut. The right one was replaced some time ago, I believe the left one is original.

Mike

mcs

What brand and where do you guys get struts from?

Arnott don't seem to post internationally, and I am sure the dealer here would want about a hundred and twenty-twelve million for one.

My car has the sports air also, so are the struts different or is it all in the ECU? (I know the part numbers for the struts are different but are they actually changed?)

Also, is there any worth to the remanufactured ones?

Cheers guys.

Mike