Projects & Repairs --> Collision --> Jeep Wrangler Cowl Area

Body repair on a 2006 Jeep Wrangler.

Collision Repair:

Repairing The Cowl Area On A Jeep Wrangler

  • Pulling Dented Metal With A Frame-Straightening Machine
  • Shrinking Warped Metal To Create A Smooth Surface

In This Article:

After the fenders and hood are removed, a frame straightening machine is used to pull out dented metal. Minor bumps in sheet metal are removed with a professional metal-shrinking technique.

Related Articles:

Skill Level: 4-5 (Advanced to Professional)

Time Taken: A Couple Of Days

By Jim Wilk, Licensed Auto Body Technician

Introduction:

This 2006 Jeep Wrangler is owned by two mechanics who repair and sell Jeeps as a hobby. This Jeep had collision damage in the right front area.

After repairing the suspension, they asked me to repair the cowl area and fender line. 

 

First thing I did was examine the damage. 2006 Jeep Wrangler with collision damage to front end. 

 

 Wrinkle in sheet metal side panel on Jeep Wrangler. The most visible damage was this wrinkle in the side panel, just behind the cowl.

Upon further inspection, I noticed more damage under the battery mount.

 

The combination battery tray / inner fender support bracket had been driven back in the collision. This area will have to be repaired first, so I removed the battery and bracket. Battery mounting tray needed to be removed because it was bent. 

 

 Automotive frame straightening machine.

The Frame-Straightening Machine:

I removed the tire and braced the frame off the floor with wood blocks. Next I anchored the frame with chains to the floor anchors mounted in the concrete.

 

 

I pulled from a bracket welded at the top of the damaged area. Using the frame straightener to pull dented steel in firewall area. 

 

 Safely using frame straightener by staying clear of chains. I have lived this long by following the safety rule of staying clear of the pulling area.

I placed a hydraulic jack under the floor pan area and applied upward pressure to the buckle down there.  

 

Having already removed the battery tray, I threaded special forged eye bolts into the battery tray mounting holes.

Then I pulled each hole, one at a time, until the firewall sheet metal looked flat.  

Pulling dented car body with forged eye bolt. 

 

 Repairing collision damage by pulling on a clamp attached to edge of sheet metal. Once the pressure was relieved from the inner area, I moved to the cowl area.

To fix the long wrinkle, I started pulling at the bottom and worked towards the top.

With pulling pressure applied, I started working the buckle area with a wood block and hammer. (I found that flat wood works well with today's soft metals)

 

I threaded the eye bolt into one of the fender mounting holes and started pulling the outer side panel, while working the buckle. Pulling dented body metal. 

 

 Using welded pull blocks to straighten body on Jeep. To pull the outer lip of the side panel, I welded pulling blocks to the lip.

 

I started at the lower block and worked my way up, carefully hammering the metal as I pulled. Pulling the dent requires progressing from bottom to top. 

 

Metal Finishing:

 Jeep body damage after pulling with frame straightener machine. Once the structure and metal had been pulled to the original shape, I began the metal finishing process.

 

First I stripped the paint and primer of the metal area to be worked.  Collision damage area after paint had been sanded off. 

 

Experienced Pro Technique -
Metal Shrinking:

After finding a slight outward hump in the panel, I decided to shrink the metal in this area.

Using the frame straightening machine, I applied a pulling pressure to the edge of the panel. With a torch, a shrink hammer, and a cold wet rag, I started shrinking small spots, working my way from the beginning of the hump to the edge of the panel.

The Procedure For Shrinking Each Spot:

 Collision repair, shrinking metal with a welding torch.

Step 1:

I used an oxy-acetylene torch (equipped with a welding tip) to heat an area the size of a quarter.

I applied heat until the spot was a dull cherry red color.

 

Step 2:

I carefully tapped it with a shrink hammer until I could see the end of the ridge-shaped hump just starting to flatten out.

My goal is to make that end of the ridge move towards the edge of the metal panel.

Metal shrinking involves tapping with a shrink hammer after heating. 

 

 Cooling the metal with a cold wet rag to complete the metal shrinking process.

Step 3:

After hammering the hump, I quickly wiped the metal with a cold wet rag.

When I cool the metal in this manner, I can actually feel the metal tightening under the cold rag, and I can see the ridge begin to disappear.

 

After shrinking the metal, I ground down the surface with a 36 or 40 grit sanding disc on an angle grinder.

Then I applied a light coat of plastic body filler.

After metal shrinking the area was sanded with coarse sandpaper. 

 

 Thin layer of body filler is applied to smooth out the collision repair. Then I sanded the filler until it was smooth and level.

I power-sanded this area with 80 grit sandpaper, then I hand-sanded with 150 grit, followed by 240 grit.

 

I mounted the fender to the body, after the hidden edge had been primed and painted. We always pre-paint the hidden edges to completely seal them and better resist corrosion.

We simply use spray cans of etching primer and enamel spray paint that closely matches the car's color.

06 Jeep Wrangler collision repair, cowl area, with fender installed. 

 

 Matrix primer on collision repair area. Then the area was primed with Matrix System MP-700 (super polyester primer surfacer). This primer has a one hour drying time. 

Then I sanded it with 400 grit sand paper.

 

Painting the front of a Jeep was done with the hood off, to do the job properly. Painting Jeep hood and repaired body area.

We used Matrix System's MPB Premium Basecoat with MS-42 Premium High Solids Clearcoat.

Jeep Wrangler collision repair after painting. After the painting was completed, the jeep was returned to the owners for assembly.

 

View of repaired area.

The owners will apply the Jeep emblem.

Collision repair after completion. 

The work in this article was performed at R-TECH Auto Body in Traverse City, Michigan.

 

More Info:

Tools Used:

  • Basic Mechanic's Tools
  • Automotive Frame Straightener
  • Oxy-Acetylene Welding Torch
  • Shrinking Hammer
  • Rags
  • Dual-Action Sander

Materials Used:

  • Sanding Discs, 36 or 40 grit
  • Sandpaper: 80, 150, 240 grit
  • Auto Body Filler
  • Etching Primer
  • Automotive Paint

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Written April 28, 2008