How to spot rust damage repair in undercarriage? (1 Viewer)

[rtong1234]

With so many different ways to convert, remove, and repair rusted areas in the undercarriage, I am concerned about buying a FJ80 advertised as rust-free but may be "covered up" in some way. How can I tell if that's the case? Is a rust repaired undercarriage that looks clean something I can put confidence in?

Thank you for your thoughts.

 

[BILT4ME]

Use a magnet for bondo cover up.

Use your eyes to see if something is uneven.

Trust your gut to determine if someone is lying or something does not feel correct.

You're in SoCal. Not much rust there compared to the Midwest or east coast. In your area, surface rust is enough to make most people run away.



Carry a chicken with you. If it will fit through a hole in the side of a body panel, then it's actually rusty. Otherwise, it's rust-free.

 

[Kernal]

Also check where the vehicle spent most of it's life, it could have started life where they use rock salt on the roads in the winter but then moved when a second, third, --- owner took it to Cali.

These came from the factory with brownish waxy coating sprayed on the undercarriage, often you'll see it's still present if it hasn't been pressured washed or steam cleaned. IME that protective coating can remain soft even after 25 years.

Here's what I look at:

Check the rear wheel wells, frton and rearward surface, for rust.

Look up around/above the spare tire, for some reason that area seems to rust (in areas that use road salt) before other areas underneath, maybe because it didn't get sprayed at the factory??

Check around the windshield gasket where it meets the sheet metal, look for "paint bubbles" (which means there's rust holes developing underneath).

Check around/under the rear hatch dust (wind) deflector mounts if it has one. Those black plastic mounting brackets are rust magnets and often the first place to show rust IME.

Look inside the rear cargo area, remove the panels, look and feel down into the quarter panel cavities. Not uncommon to find dirt but take some photos to check for rust.

Check the rocker panels ie: body panel under the doors especially the rearmost 8-10 inches. Also check the inside lip at the very bottom of the doors, lift up the weatherstrip out of the way to check for rust underneath where the factory bead of seam sealer is applied. Also check the underside inner lip of the hood especially the front inner aspect of the hood, where the seam sealer is located.

With the hood open check the nuts, botls, brackets, fasteners; if those are rusty then it may have rust elsewhere. IME when someone tries to cover up body or undercarriage rust they usually forget or don't take the time to fix/repair/replace hardware in the engine bay.

Helps if you take some good photos and post them up here.

 

[rtong1234]

Also check where the vehicle spent most of it's life, it could have started life where they use rock salt on the roads in the winter but then moved when a second, third, --- owner took it to Cali.

These came from the factory with brownish waxy coating sprayed on the undercarriage, often you'll see it's still present if it hasn't been pressured washed or steam cleaned. IME that protective coating can remain soft even after 25 years.

Here's what I look at:

Check the rear wheel wells, rearward surface, for rust.

Look up around/above the spare tire, for some reason that area seems to rust (in areas that use road salt) before other areas underneath, maybe because it didn't get sprayed at the factory??

Check around the windshield gasket where it meets the sheet metal, look for "paint bubbles" (which means there's rust holes developing underneath).

Check around/under the rear hatch dust (wind) deflector mounts if it has one. Those black plastic mounting brackets are rust magnets and often the first place to show rust IME.

Look inside the rear cargo area, remove the panels, look and feel down into the quarter panel cavities. Not uncommon to find dirt but take some photos to check for rust.

Check the rocker panels ie: body panel under the doors especially the rearmost 8-10 inches. Also check the inside lip at the very bottom of the doors, lift up the weatherstrip out of the way to check for rust underneath where the factory bead of seam sealer is applied. Also check the underside inner lip of the hood especially the front inner aspect of the hood, where the seam sealer is located.

With the hood open check the nuts, botls, brackets, fasteners; if those are rusty then it may have rust elsewhere. IME when someone tries to cover up body or undercarriage rust they usually forget or don't take the time to fix/repair/replace hardware in the engine bay.

Helps if you take some good photos and post them up here.

Bro, thank you for sharing your experience and insights. Love all of the details. Super helpful. Have a fantastic weekend.