I suppose these are the same as the alpine ones, we've done this on a couple cars as most of 'em go flat and don't seal anymore... I think it's a rather easy job...
our cars mostly leaked when not being driven for a longer time and didn't have much trouble when being driven rather daily...
'68 Sunbeam Rapier fastback {B341006846 OD/LHO} '73 Sunbeam Rapier fastback {AAD 781863 } I like a car that looks normal but really knocks your socks off!!