I just replaced the air compressor on my 2008 LR3 and I’m still gettin a suspension fault reading after driving about 20 miles (drives fine but light comes on). My front right is sagging when it is off and parked… just the right though, not both sides. My mechanic says I need to replace both struts.. if only one side is sagging, wouldn’t that mean only one side is failing and therefor both wouldn’t need to be replaced? could it be something other than the struts causing one side to sag

 

A common thought is to replace the both even if only one has strut has gone bad. The theory is the other one is most likely going to fail in the near future and therefore go ahead and replace it.

 

Also, the struts air spring and the shocks and you should always replace both shocks as a pair. I suppose you could get a replacement air bag and swap it over, but the age of most of these cars, they are probably due for a shock replacement anyway.

 

Before changing struts, check for leaks with soapy water. include the front valve block as well. The strut may not be faulty. The front valve block can have weeping seals so for a few dollars you can get a kit from eBay. a cheap check. If strut has a leak then change both sides as otherwise the shock absorbers will be different.

 

Probably a front valve block leak.