MG Car Repair: brake warning lite valve, safety warning system, differential pressure

Question
Is it necessary to keep the warning valve in the system

Answer
Hi Jim,
The differential pressure warning light and valve are there to warn you that one circuit is less pressure than the other, which means you have a problem in either the front or the rear system. Some people don't know that a soft pedal is anything to worry about. While a mechanically inclined driver would know that.
Now lets say you know this and it is not a problem. Then you let a person who does not know this drive your car or you sell the car like that and the brakes don't stop the car because one circuit is failing and there is an accident. It would take very little investigation to find out that you disabled the system. Guess who is liable? But as far as function of the car, the valve and light are not necessary. It was just a safety warning system for non mechanically inclined drivers. However it may also be a federal law item, keep that in mind.
If you have a leaking one, why not just put the two tinny "O" rings in it to stop it from leaking?
Howard