having similar problems with my machine too, i had suspension checked, infact dismantaling for removal of rack was under way but called it off, in short in my case its 100% rattling rack on bumps, now question is is this rack repairable as for my model its damn expensive, all mechanics says its not repairable.
secondry question, currently PS fluid is not reducing, is there any harm riding car with this anamoly? how long it will take to reach point of no return and eventually change is required.