Rear left air suspension goes down sometimes
 

This is for a 2000 with rear air suspension.
ok so I recently replaced my rear left upper control arm.
I unplugged the self leveling sensor and I let air out the system.
So I put everything back together the bags filled right up with
air and everything was fine.
The next day the X5 was down to the ground on that side.
So I turn the car on and up it goes. Now a week later I was
driving with 3 passengers in the rear and the self level suspension inactive came up on the dash. I immediately stopped and see the left side is down once again.
The next day I turn the car on and the suspension goes right back up again and the suspension inactive error goes away after 5 mins of driving.
I get to work park the car and 5 mins later the suspension went back down. I opened the door and back up it came. Left it sitting came back 8 hours later and this time it didnt go down.
So now my question is do I need the self leveling sensor or
do I need a new air spring.

Did you disconnect any lines to let the air out of the system? You may just have an air leak from that.

Yeah I disconnected the air lines. I sprayed some soapy water on them and It doesn't seem to be leaking anywhere on the lines. I also checked all the air suspension fuses and they are fine.

Hmm, the fact you say there was an occurrence where it did not go down after 8 hours of sitting makes me think it may be a sticking/valve with dirt in it.

I took the sensor and cleaned it. I will see if it worked tomorrow morning.

Check to see if there are tiny little cracks on the airbag near the bottom, you should be able to find a picture online.

I just replaced the air spring. Gonna see what happens tomorrow
Morning.

Ok update for anyone with this issue searching.
This morning the rear did not drop. The new
Air spring solved the problem.

Was there a tear on the old air spring?

a few very small tear around it. Really have to see it up close with a lot of light
to see them.