Repair rusted-out tailgate post

Question

2010 Silverado 1500; 500,000+ kms

I have a pickup truck that has heavy rust damage to the tailgate post. The rust will eventually spread to the tailgate cable pin area, causing a safety issue.

How can I repair the tailgate post using basic tools/skills so that the cable pin is sound?

Answer 1

Solution:

I can attach a steel plate to a strong part of the box. The plate projects out to the tailgate post, replacing the rusted-out portion of the tailgate post.

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Steps:

Remove the tail light.

Remove the corroded steel bracing inside the truck box side to make space for the plate and make room for me to work. I used a small cordless reciprocating saw because it could reach into tighter spots than a full-sized reciprocating saw.

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Drill the holes and bolt a 12"x12" - 3/16" thick steel plate to the box body.

Cut off the excess steel from the rear of the plate using the reciprocating saw.

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Various prep steps:

• Remove the steel plate, clean it with brake parts cleaner, and paint it with brush-on white rust paint.
• Apply rust proofing to the truck box behind the plate area since that part of the truck will be inaccessible after the plate is installed.
• Cut out the rusted portion of the tailgate post using the reciprocating saw.
• Clean the tailgate post with brake parts cleaner for painting.
• Re-install the plate.
• Install an L-bracket on the plate to use as a holder for one of the pins of the tail light fixture, since the factory bracing was rusted-out and removed.
• Install the tailgate cable pin and the tailgate latch pin bolts.

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Install the tail light.

Paint the tailgate post with brush-on rust paint. Blend the paint into the rest of the truck using white spray paint.

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Complete.

Now, the tailgate cable pin is located in 3/16" plate steel, securely bolted to the truck box, which should be plenty strong.

To do: Apply undercoating to the inside of the truck box side to prevent future rusting. Also, repair the hole in the fender, which likely caused the tailgate post to rust in the first place; the other side doesn't have a hole in the fender, so the tailgate post isn't rusted as badly.