The original rubber all over my 1975 230 seems to have perished in the tropical heat. Just replaced the bearing covers on one axle, but more problematic is the probable rupture of the diaphragm in the booster brake assembly. The brakes hiss with no power on application, while the massive suction of air from the engine results in a disturbingly violent judder. Does anyone know where it is possible to obtain a replacement diaphragm? All the local experts recommend buying a used power brake assembly, although it seems to me that a new diaphragm would be a better idea, as a used unit is difficult to source, and may pack up as fast as this one did... Does anyone have experience of dismantling the assembly? Haven't tried it yet, but perhaps just the valve is stuck, so it may be worth a look...

Thanks in advance for any tips you can offer!