A friend of mine has a td5 which is currently on airbags however he's just got a full set of springs for it 2nd hand which I'll be fitting soon as both his rear abs leak. I've been told that they are sided is this true and how do I tell the difference? Will I need to change all 4 or just the rear? Mine was done before I bought it. Also which fuse/relay will I need to remove for compressor etc. Cheers, guys.