91quattro

Just noticed this morning the front right of the car is all the way down. The right rear is also a bit low, but the front right is definitely the lowest. Left side is fine, both front and rear. I'm suspecting an air leak in the front right strut.

VCDS shows no faults.

Some background: replaced both front struts at 83K...3½ years ago....with rebuilt Arnotts. The car has 106K now.

A week ago, I rebuilt the compressor, putting in a new piston ring and seal. It had been a little noisy and I thought I would do some preventive maintenance. The job went as expected and afterwards the compressor seemed fine, quieter and working normally, until this morning. I am wondering if the compressor, with higher air pressure now, may have "pushed" a leak in the strut. Otherwise it seems too coincidental.

The other clue - I ran VCDS this morning, and noticed an error code in 34 - Air Leveling. Cleared the code and ran a full scan. While the scan was going on, I heard the compressor come on and pressurize the system 2 or 3 times. Once it was at full height I tried to listen at that wheel well and (it might be my imagination) I think I can hear a slight air leak.

Any suggestions? Time for a soapy water spray test?

Only 23K miles since these new struts - is that typical for a rebuilt Arnott? And, is it normal for VCDS not to show any fault codes in this situation? Any chance it could be the block (without any VCDS codes showing up)?

91quattro

OK new development. It's been an hour or two, just went and ran VCDS scan again...and now I have this error code:

Address 34: Level Control Labels: 4E0-910-553.lbl
Control Module Part Number: 4E0 910 553 H HW: 4E0 907 553 F
Component and/or Version: LUFTFDR.-CDC H06 4480
Software Coding: 0012210
Work Shop Code: WSC 02313 785 00200
VCID: 285F87AA9B5DBC0181-807C

1 Fault Found:

01575 - Control Switched Off
000 - -
Freeze Frame:
Fault Status: 11100000
Fault Priority: 4
Fault Frequency: 1
Reset counter: 19
Mileage: 170881 km
Time Indication: 0
Date: 2017.07.26
Time: 10:54:18


plus the Green and Yellow lights are both on. Also, Dynamic and Lift are both grayed out, but Comfort and Automatic are still there (it's in Comfort mode at the moment anyway).

One more possible factor - lower control arms were replaced a couple of weeks ago by an indie shop. So they had to disconnect and refit the suspension level sensors when they did that. Don't know if that could be a possibility?

At this point I can't see how to lift up the right side of the car to spray anything under there. Any ideas or suggestions are appreciated!

ltooz_a6_a8_q7

How I raised mine @3:40 in the video

Cheers,

Louis

91quattro

OK got the car on a jack stand. Sprayed soapy water and none of the rubber surfaces/joints seem to be leaking...but it looks like bubbles are forming around this brass fitting. I'll try tightening it...is this part of the strut?

91quattro

OK, tightened, and no more bubbles, but the car will still not lift the front right side...I'll let it all rest a while, I don't want to burn out the compressor.

MP4.2+6.0

Yes, let it rest some pending re check. The base of that fitting you pictures is part of strut and not replaceable or repairable typically--beyond tightening the nut. Carefully that is--you really do not want to snap it off or strut is done.

91quattro

Thanks, I couldn't find it listed anywhere and thought it was probably part of the strut. I loosened it just enough to hear the air escape, then tightened just enough to pinch it off and stop the air bubbles. I can still hear the sound of a slight air escape in that wheel well, I just can't see it. Easy to tell when I compare it to the left side wheel well - which is dead silent.

ltooz_a6_a8_q7

I think you can remove it and add glue on it. The original one was a pressed fit, but this one is not.


Cheers,

Louis

91quattro

I'll check out those hex bolts, thanks Louis.

I just started up the car again...cleared all codes, and none returned. Great! All 4 height modes were available - Lift, Comfort, Auto, Dynamic. Went to Lift, then back to Comfort. All good. Then I went through the wheel height recalibration - also good. Measured the heights - all OK. Successfully saved the heights, and the compressor raised, and then lowered etc. Rescanned the whole car again - no codes. But after a minute or so I noticed that Lift and Dynamic were now grayed out. Then I shut the car off, and within a minute the right front corner was sitting on my floor jack again. It had dropped about an inch. It seems to be a slow, steady leak.

d6lc

Did you get this fixed?, did the Arnott need replacing?, I ask as I have the same issue with a 2 yr old Arnott