This is the lower left hinge.

This hinge (lower left rear door) is common with the front left door lower one. 

This is the upper left hinge.

Make sure that all hinges are properly cleaned before applying primer.

Choose the hanging method of painting as it is more convenient.

First layer of primer.

The hinge after the second layer of primer (allow 24 hours between application)

First layer of Rosso 130 paint.

Second and final layer Rosso 130.

Remove hinges from the door. Since access is very easy in rear doors, there is no reason to remove the door as done on the front ones. 

Wrap the front & rear window frames with a piece of clotch (preferable a towel) and all together with a piece of rope.
This way the door will not sag and miss the proper alignment.

That's the lower hinge removed. Undo the tree bolts (pillar side) and the two remaining (door side) and then use a wedge or a knife to break the seam sealer.
Don't forget to stick masking tape to the edges of the door as accidents are easy to happen.

All cleaned up and ready for the new hinge.

Old and new hinge (left to right).

Spacers transferred from the old hinge.

New lower hinge attached temporarily.

Spacers for the upper hinge to be used on the new hinge.

Upper hinge installed and bolted up. Seam sealer has been applied around the hinge to prevent water entering the boxed sections.

Do the same for the lower hinge.

Inner side view of the upper hinge.

Inner side view of the lower hinge.

Prepare the hinges to be painted. Mask the surrounding are using large sheets of masking tap and paper.

Make sure that the masking covers a large area.

Make sure that the masking tape and paper has covered every recess and hard to reach area as paint will go everywhere and possibly overspray plastics etc.