Volvo Repair: 93 Volvo 850, ac condenser, volvo 850

Question
Recently when I brake @ high speeds, 850 shakes as if i were pumping the brakes. Is this the ABS or do my brakes need  work?

Secondly I have had AC issues, dealer had inlet valve, pressure monitor and system recharged @ $500. It was fine for 6 weeks then after 10-15 min, it would blow hot then cold after shutting it down. Dealer stated that I needed a new compressor,cost $1200!! Are there any options or could it be something else.

Answer
with shaking when braking you need new brake disc .
with ac problem it is possible you have bad compressor try this first before you replace compressor bypass the overheat switch on compressor removing that you will not have control over the ac compressor when it overheats it will just size up and brake the drive belt im most cases i never sizes up but that just for you to know .i bypass many times on many car the overheat sensor and i worked fine for many years after .aslo clean you radiator and ac condenser from dirt if you have turbo  than clean intercooler also that will improve air flow witch keeps ac cool and engine also  try that first before replacing ac compressor .