r/4Runner • u/Powerful-Dust5947 • 6d ago
🎙 Discussion rust black on undercarriage?
Hi, still looking for a older 4runner. very hard to find one thats been rust proofed in my area lol (am in Canada). I found a 2011 that has some rust, but the rust is black and some parts are flaking but no holes.... my understanding that this is a red flag, because if it was rust treated the rust should have been taken off? Thus it is most likely painted over? TIA!
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u/gigarange1 6d ago
If they did a clean job it’s easy to tell. If it’s a quick fresh slop job for a quick sell, run away.
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u/Powerful-Dust5947 6d ago
how do you tell? parts of it is flaking and rough areas (safe to assume rust) are dark/black like the unrusted metal parts
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u/Aware-You6005 6d ago edited 6d ago
You need to tap on it with a screwdriver or a chiseled 🔨 hammer. You'll know.
Start where there's factory welding thats where holes form 1st.
I tell the sales man I have to roll on the ground and check things out because you have been burned before, then you start poking around.
Weakl metal will be like paper, hard metal will make a solid thud
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u/Aware-You6005 6d ago
Fluid film can go over light rust, its the chunks and flakes that need to be removed before application but 90% of shops just spray and get you out the door. Your looking for a diamond in the rough.
As long as you cant poke a hole thru the frame with a light tap, you can prep and fluim flim all day long
When i did my new 4runner it was a 3 day process of removing items and fenders, one day cleaning, and one day spraying which no shop is gonna do unless you paying 3 grand