What is the Difference between RUSTPROOFING & UNDERCOATING?

[dr. d]

Hello Sir, just a follow up here.

You mentioned "heavy metal suspension parts underneath", since 4 years na yung unit ko, napansin kong may mga kalawang na yung hub or yung kinakabitan ng mga gulong(not sure exactly kung anu tawag sa kanila), and yung axles, parts nga ng suspension and some metal parts underneath. Sa pagkakaalam ko, hindi nmn naa-undercoat tong mga parts na toh. ibig sabihin ba na repaint ang gamot? san may nagpapaint ng mga parts na to?

I ask several shops dito sa may malapit sa cash n carry makati, lahat sila ang sagot eh "baka undercoating sir?" in which gusto ko sana paint tlg, particluarly sa mga parts mentioned.

undercoating is usually done on the car's sheet metal and "chassis".
suspension parts, steering and brake parts are usually not undercoated. napaka-kapal ng metal na yan. even if it started rusting, the metal is so thick, it won't weaken the part significantly during the entire lifespan of the part (or the car!).
personally, i'd get slightly worried if the axle rust shows pitting already. in which case, i'd just clean it with wire brush, turco it, then hand-paint with whatever fancy color strikes my fancy. but black is my default color. heh heh. it's DIY-easy, sir. and the part is built to take punishment. you can't harm it, even if you wanted to.

i know of some folks who will have their car's underparts painted, but these are more for aesthetic purposes, and not for longevity.

one notices, today's cars are so well-made and factory rust-proofed, hardly any rust, even after a decade on the road.
just looking around on the road, rust-free 20-year-old cars are common. corolla XE.. XL.. gli... sentra EX.. SS..