You should provide more info.

Mr. MB has a good reputation. It's likely that if it leaks a little as old MBs are prone to, it's OK to live with the leaks and Mr. MB was just trying to save you a load of money. LA shop rates are probably around $100/hr and chasing fluid leaks can get very very expensive at that rate. The car has to come apart to fix most of them, which takes time and costs the owner big money. For example: the rubber seal may only be 5 or 10 bucks, but getting to it requires pulling the engine and transmission, thereby making the cost of fixing the leak uneconomical. If you have multiple simultaneous leaks as is commonplace it would be cheaper to buy a new car than have a good mechanic like Mr. MB fix those leaks. Slow, weeping leaks will not kill the car as long as you keep an eye on the levels and don't run low, which is likely what Mr. MB had in mind when they said don't worry about it. I'm sure they tire of customers getting sticker shock from what the customer thinks is going to be a cheap repair.

A serpentine belt will not show signs of wear from the car sitting outdoors. If this was true every car in the world would need new belts every day. Engine heat and age are what wears a belt, not parking outdoors.

If you are turning the wheel to full lock in either direction, the pump will make noise. Try changing your power steering fluid or resealing the pump.

From what I have read and understand about Mr. MB Motors, it's a very good shop. So I would have to say no you haven't been ripped off.

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'02 BMW 325i
'85 300D 450k
'93 190E 2.6 170k(killed by tree)
'08 Ducati Hypermotard 1100S 6k
'06 Ducati S2R800 14k(sold)