Volvo Repair: Brakes and Turbo/oil issue, rear rotors, turbo oil

Question
Dear Regis,

I am looking to buy a 1987 740 Turbo from its second owner. It is just reaching the 130000 miles mark. When asking about the turbo, the current owner told me that his mechanic had told him that it is around that mileage that it usually goes. He also pointed out the fact that he puts about 1 quart of oil every other refueling, and that would be linked to the turbo seals wearing out.
What is your opinion about those matters?
What would happen if the turbo were to fail/break down?
What kind of checks (if any) can I do to verify the status of the turbo?
How much should I be prepared to pay to get it changed?

The only other issue was with the brakes: when I apply pressure, I feel a fairly noticable vibration in the brake pedal (actually more like an oscillation). Could it be the master cylinder, or is it something else?

Thanks for all your help and time,

Mathieu

Answer
it could be going bad you would need to remove the hoses to the turbo and look for signs of oil in them or blue smoke out the tail pipe especially on start up.the turbo could sieze up or start leaking more oil and blowing more smoke.I am not sure omn the cost I have not done one in a long time.

the brakes sounds like bad front or rear rotors.if the steering also shakes when braking it would be the fronts if it does not it cold be the rears.