brake fluid leak---master cylinder or booster?

I have a leak where the master cylinder bolts to the booster. Is there a way to determine which of the two is faulty? I'm thinking its the master cylinder.

I also need four rotors and brake pads, mechanic's estimate is $800 which seems like a lot to me but I'm gettin' too old to do the work myself. Also needs tires soon.

95SC has 125k miles on it, has been a good car for three years. I'm second owner, had 90k on it when I bought it for $3k. I've replaced the SC coupler, EGR, and had the steering column wobble repaired. Also replaced air shocks, and had a complete tune-up at 90k miles.

The car is totally stock and all the accessories work. Interior and body are perfect.

My dilemma now is whether to spend money on needed repairs/tires (about $1500) or sell the car for $2k and get something with AWD which would be nice where I live in Northern Nevada.

If I do the work and keep it I'll be into the car about $6k total which is ok except I wonder how much more stuff is about to go wrong.

I just missed out on a 98SC Riv with 42k miles for $5200.

The Brake Booster doesn't hold any fluid whatsoever. The seal on the rear of the Master Cylinder goes bad, and can leak into the Booster. The problem with that is, if the Booster fills up with enough brake fluid, you need to replace both, as the fluid will damage the seals inside the Booster.

Chances are, you just need the Master Cylinder. It's rare that the Booster gets damaged, I just don't want you to have any surprises.

$800 seems a bit steep for Riviera brakes.....quite steep actually. Given that he's not the dealership, your mechanic is probably getting aftermarket parts, which can be had by him quite cheaply. Even at $50 for the pads, and $50/rotor, you're only lookin at $300 for parts. Let's say $400 with markup. Another $400 for labor when EVERYTHING is being replaced is a bit ridiculous.....just sayin.