Tech – How To Install Rust Repair Panels

From Moss Motoring 1984

As most of our readers know, Moss Motors sells a wide range of Rust Repair Panels. We are often asked how easy it is for the amateur to install them. Provided you have the right equipment, a reasonable level of mechanical aptitude and a car that is not totally rusted out, the procedure is quite straightforward. Using these pre-shaped panels is infinitely preferable to trying to repair rusted sheet metal from sheet-stock, so, even if the job requires the ser­vices of a professional body shop, Moss repair panels cut costs and make for a much better job.

As a guide to how easy the job is for an amateur restorer, we asked our Moss-SYE manager, Peter Cosmides, to detail his experiences with installing rear fen­der repair panels on an MGB. As you will read, a very satisfactory job can be done at home. Peter presented the procedure as a series of steps, as follows:

1) Collect the equipment necessary to do the job. This includes: An electric high-speed grinder with cutting disc attachment; a hammer and sharp cold chisel; gas welding equipment; your Moss Motors rust repair panels; a piece of chalk or welder’s marking crayon; jack and stands.

2) To prevent heat damage to the car’s interior, remove the seats, peel back the carpets from the area around the inner fender, and buy yourself a can­dy bar with the change you found under the seat. Jack up and support the corner of the car, and remove the wheel. Remember, if you’re working inside a garage with welding equip­ment, remove cans of gasoline, and make sure your home-heater pilot light is alight (or else turned off completely).

3) Take your repair panel, and place it over the area it will replace. With your chalk or crayon, carefully mark the fender where it is to be cut. Be sure to allow for the W of the fender that has to cover the lip of the repair panel! Cutting with a disc grinder is much better than using your welding torch, because the heat will warp the fender. Care is important when cutting; one wrong cut and you’ve got another repair job! The inner rocker panel protrudes inside the fender; don’t cut into it! You might want to : (a) Cut a square “window” in the rusted section you are about to remove, to see what’s inside, and (b) make your first cut about W below your marked line, so that you can “trim to fit”.

4) The top line you marked is the only place that needs to be cut. The other edges are spot-welded and can be separated with your hammer and chisel (or by drilling out the welds).

5) Once the old panel has been removed, you can wire brush away any surface rust, dirt, etc., that is exposed. If you find any other rust holes in the inner area, if s decision time! Professional repair, small patches welded in, or fiberglass patching might be needed, depending on the extent of what you find.

7) After the welding is finished, grind the welds down and, using body filler, surface the join area nice and smooth. It is now ready for priming and painting. (Don’t forget the inside; rust-inhibiting paint or rubberized undercoating will help prevent you having to go through all this again in the future!)

Now you can begin fitting the new repair panel. When everything is trimmed and tidied so that the new panel fits to your satisfaction, clamp it in place with vise grips or C-clamps. You then carefully weld it in place, making sure you do not concentrate in one spot long enough to warp the panel.

'Tech – How To Install Rust Repair Panels' have 5 comments

  1. May 17, 2015 @ 8:01 am Orlando

    The images do not show up.


  2. August 13, 2016 @ 5:22 am Jomana

    do you think what is better for time and money is to repair panel or just buy new one ?


  3. September 6, 2016 @ 9:22 am Sam Stengler

    Interesting. Can we get pics that show more of the area that needs to be cut(and not cut)?

    Also, just read the Safety tip, and noted that the gentleman doing to grinding is almost w/o eye protection!

    Let’s lead by example, ok?


  4. February 9, 2019 @ 1:58 pm Evan Hughes

    #6 is missing from the process?


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