need to change A/C compressor

Are you sure you have a bad compressor? How do you know it is bad, testing or?

First step if it is actually bad is to recover the R134A that is in the system. Then it is a simple matter of removing the compressor, Flushing the system to remove any contaminants from the failed compressor, then install the new compressor and drier. Vacuum the system down and verify it does not leak. Then recharge the system with the amount of oil and R134A the compressor and system call for.

Do you have a gauge set, vacuum pump and the proper oil and replacement 134A?

It would be a bit easier if the only bad item was the compressor clutch. For that you could opt to only change the clutch.

You would need to have the system evacuated first before you do any repairs on the A/C system since the system could be under pressure. Also replace the drier and expansion tube if the compressor has failed internally and flush the system.

Remove or Disconnect


Negative battery cable at battery.
Recover refrigerant.
Remove serpentine belt.
Raise vehicle.
Right air deflector and splash shield.
Electrical connections at the compressor.
Compressor/condenser hose at rear of compressor and discard seals.
Compressor attaching bolts.
Compressor.
Drain and measure compressor oil.
Install or Connect

Drain compressor oil from new compressor.
Refill compressor with same amount of oil drained from old compressor. If less than 30 ml (1 oz.) was drained from old compressor add 60 ml (2 oz.).
Compressor and compressor attaching bolts.
Tighten
Bolts to 58 N.m (43 lb ft) Front
Bolt to 50 N.m (35 lb ft) Rear
Important
Any repair to the A/C compressor or the A/C belt system will require loosening some A/C bracket bolts. To prevent future torque loss after re-tightening of these bolts, the bolt or stud should be replaced with an appropriate new bolt or stud OR apply Loctite(R) 242 or equivalent to the bolt or stud threads. Follow the package instructions for best retention.
Compressor/condenser hose to rear of compressor using new sealing washers (not required to be lubricated).
Tighten
Bolt to 33 N.m (24 lb ft) .
Electrical connections to compressor clutch.
Right air deflector and splash shield.
Lower vehicle.
Serpentine belt.
Negative battery cable.
Tighten
Bolt to 16 N.m (12 lb ft) .
Evacuate, charge, and leak test A/C system.

Hope this helps.