Replacing Cycle Wings

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Here is a guide to replacing a cycle wing on a car with exposed fixings on the outside of the wing.

In replacing a cycle wing, the best advice I can give is to resist the urge to measure distances between fixing holes but instead plan to transfer fixing points from the car. 

Push a piece of card under the front edge of wing until it meets the first support. Mark the front edge of card with pencil. This will be a guide later.

Unscrew and remove wing, wire brush exposed supports and spray with satin black paint or Smoothrite. 

Stick strips of rubber on the supports (eg inner tube) if existing gasket strips are poor shape, using spray contact adhesive (cut holes to match those on supports). 
Get some Tipex ready (or paint and fine brush).

Offer up new wing. Use pencil mark on cardboard guide to work out where the front edge should sit. 

Use Tipex to mark wing through front support. Remove wing, drill pilot hole (2mm) through marked holes. 

Turn wing over and drill back through with appropriate drill size for fixings (eg. M5). 
Lightly fix the front of wing to support with two of the planned bolt / nut fixings. 

Move to rear of wing, mark holes with Tipex, remove wing and repeat. 
Spray rust protection or white grease in the ends of the supports and in and around the fixing holes before refitting.

Don’t overtighten as it will cause stress cracks around the drilled holes.

For fixings I’d suggest: 30mm stainless domed hex socket M5 screw, then stainless washer, then rubber O-ring in that order above, stainless washer and M5 nylock nut below.
Spray supports under wing with rust proofer / white grease.