Project Mini Cooper S | Magazine Series Part 7: Tackling the Metalwork on Our Mini Cooper S

Update by Tim Suddard to the Austin Mini Cooper S project car
Nov 3, 2020

Photography by Tim Suddard unless otherwise credited • Lead by David S. Wallens

[Editor's Note: This article originally ran in the July 2014 issue of Classic Motorsports; for more updates on our 1967 Mini Cooper S, visit here.]

When we bought our poor, forlorn Mini Cooper S, we knew it needed some metalwork. We could see the poorly patched holes in the floor pans and the trunk. We also spotted the rust in the cowl and along the rain gutters.

We just didn’t expect the entire car to be quite so rusty.

The entire story was revealed during the body’s visit to Blast Masters in West Palm Beach, Florida. As workers stripped away the paint and putty, they uncovered horrors that exceeded our expectations.

Damage to the trunk floor was worse than we thought. The front of the car had been hit and then badly put back together. The driver’s door was a mess of corrosion.

We weren’t totally surprised: Minis are notorious rusters. The factory’s quick production techniques, questionable build quality, and minimal rustproofing efforts made for a car that was predisposed to tin worm. If you manage to find a healthy example, chances are it’s undergone some major rust repair. It’s an inconvenient reality, but it won’t dissuade us from rescuing our car.

To solve our Mini’s issues, we needed to carefully weld a series of new panels onto our stripped and primed shell. Time to fire up the welder.

Rust Reconnaissance

Once Blast Masters returned our Mini, Tom Prescott of The Body Werks primed the entire shell with multiple coats of PPG DP40 rust-inhibiting primer.

Our entire rear seat panel, which is also the trunk floor, was rotten.

The top corner of our A-pillar was badly rusted.

Our floors were a mess, especially the driver’s side.

The drip rail had also rusted through in a few places.

Our trunk floor looked like Swiss cheese.

Both sides of our cowl had rusted through. The left side had been poorly patched, but the right side was even worse.

Our driver’s door was shot. We decided that a used door was the answer, as we were trying to keep the car as authentic as possible. Good ones are getting hard to find, but we found one at Heritage Garage.

Photography credit: Jere Dotten

Metalworking Our Mini

If you're diving into rust repair, do your repairs in the proper order, but also be sure to focus on one step at a time: The amount of work left in the overall project might scare you off.

Consider starting at the front of your car and working your way back: That’s what we did on our Mini. We began the rust repair by fixing the cowl, since it was a simple job. Plus, we couldn’t reattach the fenders until we first had a solid cowl.

Before going too far, we wanted to make sure that the front-end alignment was close. Test-fitting the front subframe ensured that we were looking good.

There’s no reason to go at this alone, either. Steve Eckerich, on the right, is an old friend of ours. While he was passing through town, we put him to work. He and Jere Dotten test-fitted the grille surround.

Once we roughed in the nose alignment, we brought in Tom Prescott, our local sheet metal expert. Our car had been tweaked, but Tom was able to bend and pry our front end back to spec. Trial and error is one thing, but years of high-end bodywork experience is needed when a car is this messed up.

Some panels just couldn’t be saved, like our front fender. Mini Mania supplied our replacement from Heritage in England. These panels, made from the original dies, fit beautifully. In fact, this company’s panels were some of the best-fitting ones we’ve ever used.

Once we reassembled the cowl and nose, it was time to tackle the floors. We cut out most of the incredibly rusty driver-side floor so we could replace it with a new panel sourced from Mini Mania.

Our new floor fit nicely. Before we call the bodywork complete, though, we have a few small dents to remove.

While the car was on its side, we removed the entire trunk floor—it was simply that corroded. After drilling out the spot welds, we finished the job with a cutoff wheel.

The new trunk floor fit was a very tight fit. Getting it in place required a bit of tapping and massaging. Also, notice that we’re wearing proper safety gear, including ear, eye and hand protection. Even when you’re not welding or grinding, metalwork can be nasty business.

Photography credit: Jere Dotten

The top of the car needed work, too. We replaced our rusty rain gutters with fresh ones.

When the aftermarket didn’t have what we needed—or we simply didn’t want to wait—we made our own patch panels with our Woodward Fab 3-In-1 Machine. It’s a cutter, brake and roller.

Photography credit: Jere Dotten

Step by Step: Rust Repair

1. No matter the location of the damage, rust repair tends to follow a similar sequence of events. Our cowl was badly rusted and needed to be properly repaired.

2. Cowl rust is a common problem on Minis, so Mini Mania makes patch panels to fit this area. This panel cost about $25.

3. Remove the outer and inner metal with a cutoff wheel to see the magnitude of the damage.

4. Sandblast the entire area to vanquish every bit of rust.

5. Notice any unforeseen damage? Source the necessary replacement panels now. We bought the outer panel from Mini Mania, but we didn’t realize we would also need to replace the inner panel. Rather than order one and wait, we used our fabrication tools to make one—our replacement panel is the one at the bottom of the photo.

6. Time to test-fit the repair pieces and the front fender. Everything fit okay? Good. Now weld the cowl panel in place. To duplicate the original spot welds, use plug welds: Drill a hole and then weld in the middle of that hole.

7. Grind down the repair, first with a 4-inch grinder fitted with a No. 24-grit wheel. Afterward, hit the repair with a No. 80-grit wheel attached to a small air grinder.

8. Now it’s the home stretch. Spray the area with self-etching, rust-inhibiting primer. Complete the final bodywork from here—not much should be needed.

8 Tips for Better Metalwork

1. Eastwood sells a kit to remove spot welds. It’s possible to do this task with a standard drill, but Eastwood’s tool prevents you from drilling all the way through the two pieces of sheet metal.

2. Don’t throw anything away until the car is done. This repair panel was intended for the lower-right corner of the cowl, but the same piece worked just fine when we repaired the upper-left corner of the A-pillar.

3. A Dremel tool fitted with a grinding tip is a great way to address hard-to-reach places that normal grinders won’t touch.

4. Before grabbing the sheet metal, first make your repair panels out of cardboard and test-fit them. You can easily trim the cardboard to get a perfect fit. Once your cardboard templates fit, duplicate the patch panels in metal. This saves time, materials and muscle soreness in your hand.

5. Old fenders can yield great material for patch panels—and you know that the sheet metal will be of the correct type, thickness and vintage. Again, save everything.

6. Common paint-stirring sticks are about the perfect thickness for setting most door and hood gaps.

7. Use markers to make notes and, well, to mark things.

8. Eastwood Self-Etching Weld-Thru Gray Primer is amazing stuff. It offers a level of protection that you can still weld through.

Where Do Minis Rust?

Photography credit: Laurent Nault

Sure, they’re fun and lovable, but classic Minis are known to rust. While some hobbyists joke that these cars rust everywhere, Mini Mania has narrowed down the problem areas:

Lower-front bumper lip: Road debris and curbs often remove paint, leaving the sheet metal bare and vulnerable.
Rear seam of the hood: The hood rests on soundproofing foam that retains water.
Lower windscreen surround, top of fender, A-panel: The box-section construction allows road dirt and water to accumulate.
Roof skin edge/drip rail: Trapped dirt and water plus worn paint equals rust.
Rain channel: As designed, it just doesn’t drain properly.
Headlamp surrounds and bowls: These rust out from behind due to accumulation of road dirt and moisture, especially in locales where road salt is used.
Lower door edge: Rusts due to blocked drainage holes.
Outer/inner sills: Very prone to rust thanks to trapped dirt and moisture.
Lower edge of body sides: More common where road salt is used.
Boot lid: It’s prone to rust along the bottom edge—the same applies to van and estate rear doors.
Rear panel, rear valance: The rear seat bulkhead, trunk floor and rear valance all like to rust.