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CJ Rust Repair: Fighting a War You Cannot Win
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CJ Rust Repair: Fighting a War You Cannot Win

Jason
Jason • March 17, 2026

Rust is the #1 killer of Jeep CJs, and living in the Pacific Northwest means your CJ is basically marinating in rust juice 9 months a year. The factory steel, combined with an open-top design that lets water into every crevice, means rust isn't a question of "if" but "how much of my Jeep is still actually metal."

The good news: CJ tub repair panels are widely available. The bad news: you're going to need most of them.

Where CJs Rust (Spoiler: Everywhere)

In order of "oh no" to "oh no no no no":

  1. Floor pans — Pull back the carpet. Go ahead. I'll wait. That crunch you just heard was your finger going through the floor. Welcome to the club.
  2. Rear corners — Where the quarter panel meets the tailgate opening. Water pools in the seam and turns steel into lace. Decorative, structural lace.
  3. Rocker panels — The bottom edge of the tub, right where mud and water sit for months. Many CJ rockers are now approximately 60% wishes and 40% Bondo.
  4. Windshield frame — The bottom channel traps water and rusts from the inside out. You won't know it's bad until the windshield wiggles.
  5. Frame — "I'm sure the frame is fine" is the CJ buyer's equivalent of "I'm sure that noise is nothing."

Assessing the Damage (Bravery Required)

Grab a screwdriver and start poking. If the screwdriver goes through, that's rust. If the screwdriver goes through and your foot follows it, that's also rust, plus a tetanus shot.

The honest condition scale:

  • Surface rust: Wire wheel, POR-15, paint. Buy your wife flowers with the money you saved.
  • Pinholes: Needs cutting and patching. Tell your wife you need a welder "for the house."
  • Swiss cheese: Full panel replacement. Don't tell your wife.
  • You can see the road through the floor while driving: You're in good company. Most of us started here.

Floor Pan Replacement: A Love Story

Full floor pan replacements are the most common CJ body repair. Omix-ADA, Key Parts, and Crown make reproduction panels. You'll develop strong opinions about which brand is better. Nobody at parties will want to hear these opinions.

Tools Needed

  • Angle grinder with cutoff wheels: $40 (you'll burn through 8-10 wheels)
  • MIG welder: $400-800 (or "that thing I bought for a project around the house")
  • Cleco fasteners: $20 (or sheet metal screws and optimism)
  • PB Blaster: $8 x 4 cans
  • POR-15 rust converter: $25
  • Band-aids: $5
  • Replacement floor pan: $100-400
  • Total money your wife thinks you've spent: $100
  • Total money actually spent: $600-1,400

The Process

Day 1: Discovery

Strip the interior. Remove seats, carpet, and whatever creature has been living under the carpet. Assess the damage. Try not to cry. Text your buddy a photo. He'll respond "that's not bad" because his is worse.

Day 1.5: Cutting

Mark your cuts at least 1" past the rust into good metal. Good metal is defined as "metal the screwdriver doesn't go through." Cut with your angle grinder. This is the fun part. Wear safety glasses unless you want to explain to the ER doctor that you were cutting a Jeep floor with an angle grinder at 10 PM.

Day 2: Welding

Fit the new panel. Trim as needed. Drill 5/16" holes every 2" along the overlap. Plug-weld each hole. Do NOT run a continuous bead — you'll warp the panel so bad it looks like a topographic map.

Stitch weld: 1" on, 2" off, 1" on, 2" off. Let it cool. Go inside and tell your wife you're "almost done." You are not almost done.

Day 3-7: Everything Else

Grind welds smooth. Apply seam sealer. Prime everything. Apply bed liner because you are never going through this again (you will go through this again).

The Bed Liner Question

After all that work, what do you put on the floor?

  • Raptor bed liner: Tough, textured, waterproof. The "I actually use my Jeep" choice. $100-150 per gallon.
  • Monstaliner: Similar to Raptor. Comes in colors. The "I use my Jeep but I also want it to look nice" choice.
  • Regular paint: Will last about 6 months before scratching. But it's cheap.
  • Nothing: The "I just spent $1,200 on floor pans and I'm done spending money" choice. Respectable.

Rust Prevention (AKA Denial Management)

After welding in new metal, you want to keep it from rusting again. This is adorable optimism for a PNW Jeep, but here goes:

Inside:

  • POR-15 or Eastwood Rust Encapsulator on bare metal before primer
  • Bed liner on floor pans
  • Keep drain plugs clear (CJ-7s have them in the floor — find them, clear them, love them)

Outside:

  • Fluid Film or Woolwax on the frame annually (smells terrible, works great)
  • Cavity wax inside body seams
  • Try not to park in standing water (in the PNW, "standing water" is everywhere from October to June)

The most important thing:

  • Don't leave a wet soft top sealed up for days. The interior becomes a greenhouse for rust. Open it. Let it dry. Your CJ is not a terrarium.

When to Walk Away

If the frame is rotted through at the spring hangers or body mounts, you're looking at $2,000-5,000 in frame repair, or a frame swap at $1,500 for the frame plus a weekend of hating your life.

At some point, the cost of repairs exceeds the value of the vehicle. We call this point "Tuesday" because most CJ owners have already passed it and kept going anyway.

Final Thought

Every CJ you see at a car show looking beautiful was probably 50% rust at some point. Floor pans, patch panels, and a MIG welder have saved more CJs from the crusher than any other tool. It's honest work, it's satisfying work, and the before/after photos will get you at least 200 likes in the Facebook group.

Your wife will like the photos too. She just wishes you'd also fix the bathroom faucet that's been dripping since March.