Syncro Fuel System - Problems
Syncros have a rear fuel filler going to a plastic saddle tank over the gearbox. The pipe running along the chassis-member under the rear wing to the tank can suffer perforation corrosion, and leak. Other parts fo the filling system can corrode/perish and subsequently leak.
Syncros are also prone to difficult filling and overflowing. This can be for a variety of reasons: overfilling (vehicle not level at pumps); tank-top vent valves sticking/being blocked; breather pipes fretting/perishing and leaking; poorly sealing fuel cap etc. The fuel ends up in the rhs compartment behind the tail-light (snorkel box), chassis frame, under rhs wheel arch etc.
Syncro Dokas (pickups) can also get fuel in the lockers due to overfilling/poor seals around filler tube as well as all the above reasons.