Grind the rusted portion with an air sander or the like.

Rust may be more extensive than it appears from the outside. Therefore, it is necessary to grind the area around rusted portion. Repair the ground out portion using body filler.
Repair of Rust and Corrosion
Repair of Corroded PanelRemoval and Installation
REMOVAL
Disconnect the 12V battery cable from the negative terminal.
Remove 12V sub battery (lithium ion battery). Refer to Removal and Installation.
Check that there is no voltage (Approx. 0 V) between power network separate relay terminal and ground and power network separate relay terminal and gr ...
Exploded View
REMOVAL
Propeller shaft assembly
: Vehicle front : N·m (kg-m, ft-lb) : Always replace after every disassembly.
DISASSEMBLY
Snap ring Journal bearing Journal Sleeve yoke Propeller shaft tube Flange yoke
: Vehicle front : Always replace after every disassembly. : Select with proper thickn ...
Commercial Service Tools
Tool name Description Drift
a: 61.0 mm (2.402 in) dia.
b: 56.3 mm (2.217 in) dia.
Installing front oil seal Drift
a: 68.0 mm (2.677 in) dia.
b: 47.0 mm (1.850 in) dia.
Installing rear oil seal Drift
a: 68.6 mm (2.701 in) dia.
b: 58.0 mm (2.283 in) dia.
Installing input oil seal Power tool
...