1994 4x4 Geo Tracker Underside Rust

[sassylady]

Howdy,

My 1994 4x4 Geo Tracker is in pretty good shape, however, I just noticed the very underside is rusting (Minnesota winters/salt).

What can be done to strengthen the underside/fix the underside?

Thanks :)

[Moses Ludel]

sassylady...Is this the rust scourge at work?  There are several types and degrees of rust.  For simpler non-perforating rust, you can find rust arresting products that transform surface rust into harmless oxides that can be primed and painted.  POR-15 is one such product, popular for vehicle "frame-off" restoration projects.  Prior to using POR-15, all paint, debris, wax and grease must be removed.  POR-15 and similar products should not be used around intact, painted surfaces.

There is also an insidious kind of rust—from the inside out.  This rust reveals itself too late—as exfoliation.  Exfoliation pushes paint away as it unfolds from rusted, underlying metal.  The area is eroding and becomes unstable and weak.  I give a repair example in my Jeep® Owner's Bible™ (Bentley Publishers).  The CJ-5's body tub required a small sheet metal section to be cut out and replaced by fresh sheet metal.  I bought the vehicle at San Diego, CA, but it came from Chicago, IL.  That was my first exposure to road salt damage.

Today, road salt rust is so prolific that one company makes replacement frame sections for TJ Wrangler Jeep® vehicles.  Frames rust from the inside out, exfoliating as the section breaks or collapses.  The frame, essentially useless, can be weld repaired and made functional.  This company does a brisk business thanks to road salt, coastal salt air and drivers wending their way through the surf at Baja.

Then there is today's epidemic of rusted fuel and brake lines.  At the magazine, you can find my coverage of how to repair, reconstruct and form brake tubing.  I cover brake and fuel line work thoroughly.  In my research, I discovered an entire "industry" related to repairs and replacement of brake and fuel tubing, most often the result of road salt damage.  Vehicle age is immaterial, the key factor is the amount of salt exposure.  In some cases, coastal air or extreme humidity can erode brake and fuel tubing:

https://www.4wdmechanix.com/video-series-how-to-flare-automotive-brake-tube-fuel-lines-and-cooler-tubing/

https://www.4wdmechanix.com/how-to-fabricating-restoring-and-repairing-hydraulic-brake-lines/

If you could post some photos of the rust you see, I can identify the risks posed and suggest an approach for eliminating the rust.  Once the rust has been identified and eliminated, I'll suggest ways to prevent rust from forming.

Moses

[sassylady]

Thank you for your response - some of the rust appears surface where it is still solid feeling.  I will need to get a pic of the underside - could be challenging...LOL

Thank you!

Kristin

[Moses Ludel]

sassylady...When you photograph (cell phone level works well in tight quarters), concentrate on the sheet metal body sills (rocker panels), the actual frame, the fuel and brake pipes and any rust that draws your attention.  We'll take a close look and go from there.

Moses

[sassylady]

Thanks - been finishing up my school year - no time yet...LOL