Quarter Panels Are Welded On, Which Changes the Whole Job

Because a fender comes off. Unbolt it, replace or repair it on a bench, bolt it back, refinish it. The panel is separate from the structure and there is nothing to cut.

A quarter panel is part of the body shell. It is welded at the roof rail, the sail panel, the rocker and the rear body panel, and on a modern van it may be structural. Replacing one means cutting factory welds, sectioning at manufacturer approved locations, fitting the new panel, welding it with the correct process for the material, dressing the welds, sealing the joints inside and out, and restoring corrosion protection to bare metal that was originally coated before assembly.

Then it has to be refinished, and a quarter panel touches a roof, a door, a rocker and a rear panel, so the blend travels further than it would on a bolt on fender.

On recreational vehicles the equivalent distinction is between a bolt on fender skirt, which is a straightforward part swap, and a bonded or riveted wheel arch section in the sidewall, which is closer to panel replacement.

By cutting it out, always. Rust cannot be treated in place with any expectation of permanence, because the corrosion continues on the back side of the panel where the treatment never reached.

Wheel arches rust for structural reasons. They are a doubled or flanged edge with a seam, they collect moisture and road salt in that seam, and the drainage that was supposed to clear it gets blocked with debris. Once corrosion starts in a seam, it separates the layers and accelerates.

The repair is to cut back to bright, sound metal well past the visible corrosion, fabricate or fit a repair section, weld it in, seal the seam from both sides, and apply cavity wax or coating inside the closed section where the eye never goes. The last step is the one that decides whether the repair returns in three years.

Filler over rust is the failure mode owners have usually seen before: it looks correct for a season and then bubbles through, because the corrosion never stopped and the filler simply hid it.

1. Assess and measure. Damage mapped, and if the impact reached the wheel house or the rocker, structure gets measured before panel work is planned.
2. Access. Interior trim, wheel house liner, lamps and glass removed as required, and on a van, upfit equipment along that wall comes out.
3. Section or repair. Either the damaged area is worked and filled, or the panel is sectioned at approved locations and a replacement section fitted.
4. Weld and dress. Welded with the process the material requires, welds dressed flat and the joint inspected before it is covered.
5. Corrosion protection. Seam sealer inside and out, primer on bare metal, cavity coating into closed sections.
6. Refinish and blend. Colour applied and blended into adjoining panels, clear carried to natural breaks, then cut and polished.

Body labour posts at $210 per hour with body supplies at $5 per body hour and paint supplies at $55 per paint hour. Corrosion protection materials are part of the repair rather than an upsell, because a sectioned panel without them is a repair with a countdown on it.

Enough to know whether you are looking at a bolt on job or a welded one, which is most of the price question.

• Look for a seam or a line of fasteners around the panel edge. Bolts or a defined seam usually mean a bolt on part. A continuous surface running into the roof line means a welded quarter.
• Check the wheel arch lip for bubbling paint, which is corrosion working from the inside out and is always larger than it looks.
• Open the door beside the damage and check the gap along its rear edge, since a pushed quarter shows up as a changed door gap first.
• Look inside the wheel house with a light for a folded or torn liner and for any bright metal where something has been pushed.
• Photograph the panel with light raking along it to reveal the true extent of the deformation.

Sibling operations sit at dent removal and repair and bumper repair and replacement. Bands are on the price sheet.