I drove a landcrab at one stage … quite liked it but apart from the oil issue, it wanted more luxurious suspension … sadly, it did not evolve well.
The offputting styling of the post-landcrab into a dinky, bland angular nothing shape … same as all the other little cars on the road … well, I’d not have bought it. The landcrab was certainly grandfather style and I was a young man then … the inline 6 and style of the Wolseley suited me better than what would be Corsas today … I enjoyed loping along, no fuss … but life circumstances intruded and it was not to be … probably fortunately.
I’m afraid his understanding of the suspension aspects is rather muddled. The Citroen Hydro pneumatic system did indeed use “Spheres” which contained a diaphragm and were pre-charged with Nitrogen gas. These screwed onto hydraulic cylinders which were pressurised with fluid delivered by the engine driven pump. This fluid transferred the movement of the wheels to the gas “spring”, and because of the pump, allowed for automatic levelling dependent on load.
The BL designs were much simpler: the early Hydrolastic units employed a rubber block as the spring. This was moulded into the top of the so-called “displacer” units, with a diaphragm below connected to the suspension arm. The space between was filled with the water/antifreeze mixture referred to, which transferred the loads in the same way. The front and rear units on each side are interconnected, and this pipe also incorporated a valve to allow the system to be pressurised with fluid. At one time, almost every garage had a Hydrolastic pump lurking in the workshop. The idea was to give a pitch-free ride over bumps, but be resistant to roll in corners. The later Hydrogas version replaced the rubber spring with a second diaphragm & nitrogen filled chamber. This was factory pressurised and sealed with a rivet. The fluid part and interconnection was exactly the same. Unlike the Citroen system there was no self-levelling, so a well loaded car always sat low at the rear.
Although the Hydrogas variant gave a smoother ride it suffered from gradual gas leakage from the “spring” chamber – there was no way of dealing with this, other than pumping some more fluid into the system to restore the ride height, or (eventually) replacing the entire displacer. They were expected to last the life of the car, which at the time was probably only 10 years or so. I encountered this on my second Maxi, and not being one to give up, spent a considerable amount of time developing a way of re-pressurising those spring chambers. Ironically, I used Citroen valves welded onto the Hydragas displacer! Sadly, the few remaining Hydragas suspended cars are living on borrowed time, as they now have virtually no springing left, and a sudden sharp bump in the road will cause the lower diaphragm to rupture. The displacers haven’t been made for decades, and used ones won’t be any better…
My father drove a landcrab, towed a caravan with it. He described it as a good tow car, better than the VW Fastback he had before. I never drove the landcrab but I did drive the Fastback.