F11 Rear Suspension

[markcp]

Hi,

One of the rear airbags was recently leaking so was replaced and all seemed to be fine. However, the car has very gradually dropped during the time its been parked up due to lockdown and when I drove it to the supermarket last week I got the chassis warning error.

I've tried a few times but the rear end won't lift so I looked and fuse 182 (one of the two for the compressor) which was blown. I tried another which also blew immediately. Any suggestions what I can try next before I have to bite the bullet and replace the compressor?

Cheers,

Mark

[Don Phil]

I've read it could be the relay for the compressor as water can get to it?

Worth a look before splashing out on a replacement compressor.

If you do need a compressor, I got mine from Aerosus, it's been fine and is a lot cheaper than the BMW part.

[stevesingo]

Fuse 182 is the larger (40A) fuse which runs the pump.

Seems your pump is dead, but as said above, check your boot floor for water, although given the lack of rain recently, it seems unlikely.

BMW recommend replacing the relay at the same time as the pump. It is an easy DIY. BMW pump is £1000ish, so aftermarket is a better value route for the pump. Not sure if the relay is available on the aftermarket.

[markcp]

Thanks for the responses. I've looked at the relay and its bone dry but that doesn't mean it can't be faulty. I may replace that next to eliminate it before things get more costly...

[74merc]

If the fuse blew, the drier in the compressor could be waterlogged. It's not a difficult job to pull the compressor out and access is easy. I took mine out yesterday to check it but it was dry, total time not much more than an hour to remove and refit. You can buy a rebuild kit with new seals and dessicant and there are plenty of videos on YouTube documenting it all.

[CourtAgain]

Hi

It could also be the air dryer beads in the compressor. The compressor contains Silica Gel beads (like those annoying little packets you might get with a new laptop case or rucksack )

Although this video is for the F15 X5, it's the same setup in the 5 Touring.

https://m.youtube.com/watch?v=dUDDH3mtjr8

I'm sure there's sites like Amazon / Ebay that sell the Silica Gel. No need to shell out £££s for another compressor.

If it is the Air Bags, buy Arrnott ones, not the cheap & cheerful stuff off the Net. HTH

[74merc]

Try 4x4airseals.com for a rebuild kit. Mine arrived this week but haven't fitted it yet. There was very little output from the compressor so am hoping it is the seal on the piston. I'm not in any hurry now as I used a bicycle pump/oil pump flexi/washer hose/jubilee kit contraption to inflate the airbags.

[Huskyman]

The dryer gel beads can be dried out in an oven. Set it to 130 and keep an eye on them until they turn blue, no need to bin them.

[74merc]

So I fitted the rebuild kit this morning and put the compressor back on the car. No joy, so I disassembled it and checked everything. All good so that only left the solenoid. I rang tech support for the rebuild kit, he suggested using WD40 to free it up. A few cycles of WD40, 12V to the connections saw it free up and make a more pronounced click when power was applied. Back on the car and it immediately levelled out. So it was the solenoid all along, despite the fact that there was very little dampness or rust anywhere inside the compressor. The seal on the piston had gone brittle too, so I think it was only a matter of time before that failed.

Edit - Diagnose Dan on Youtube has a good video on this. He chose to fit a new compressor but at the end of the video he disassembled the unit to find the cause of failure. He also found the solenoid to be the problem, so I think this may be quite common.

Edited by 74merc on Saturday 23 May 14:07