put half a cup of DOT 3 or 4 brake fluid in the pwr steering top up reservoir .
there are probably only 2 places the power steering leaks, one is the banjo fittings on the pump and the other is the lip seals on the steering box .
you can try a spoonfull of fluid up to about half a pint added depending on severity of leak ,it will take a short while to go through the system but this will usually stop the leak from the seal on the steering arm shaft at bottom of steering box, they all leak in same places you know !!. .
ive used this fix on range rovers and land rovers will no ill effects and ran the vehicles for years afterwards with only topping up of reservoir with dexron fluid reqd annually .
power steering will work as normal afterwards , it wont mess up the pump and the pipes will last longer than the vehicle will last you no doubt ..
dont waste youre money on additives because if you actually knew what they contained youd probably find out its chemicals the same as brake fluid contains .
all the additives youll buy are just "seal swellers" and brake fluid will do exactly same function but at cheaper cost ..