The adjustable shocks are shorter than standard 16's and have a spacer at the top. The springs have chunks of rubber inserted in the coils and additional rubber spacers at the top

The shocks are adjusted by this pump that is bolted onto the underside of the loadbed in the locker...

which is controlled by this mechanism in the back of the cab..

The shocks are oozing stuff and when pumped up they just sag down again so I have air and fluid leaks. I tried cleaning of the shocks to see if I could identify a brand with no joy as my first option is to see if I can get them repaired/serviced. Anyone recognize them?
If I end up replacing them http://www.syncro.org/suspension.html recommends part number 251 513 031 N 16'' syncro shock. Anyone got a tip and part number for a suitable spring?
Cheers
Steffan