Unimog Club UK

Hi everyone,
I have owned a 1983 U1200 since last February.
I bought it from a tree surgery company in Hertfordshire, they were selling two at the time so I bought the one I reckoned was best.
Since then I have had all the wheel bearings and some of the seals replaced professionally then started work on it myself. I have put new tyres on it, 395/85 x 20s, so that it runs a bit faster on the road, and it has a more imposing, taller look about it.
I sold the chip box and auto pick-up hitch it came with and bought a drop plate for towing with a regular 50mm tow ball as this is of more use to me.
Also fitted trailer/caravan towing electrics.
I've fitted a radio and speakers, cleaned and painted all the cab floor under the sound-proofing, fixed one or two other bits that weren't working, and have recently had a new 3mm steel floor welded into the tipper body. Currently painting all the sides etc to smarten it up for going to shows, tractor runs etc.
One problem I have is that although 4WD works OK (second position on the switch), diff lock (third position on the switch) causes a big air leak from both axle casings via the axle breathers. I suspect that seals on the diff lock pistons have let go. Is this the case, and how difficult is it to replace these? Any advice on this would be most welcome.
Malc.

Welcome to the forum malc, nice looking mog you have, hopefully you'll manage OK with the difflock seals