While preparing ASW 28 serial 28048 for annual inspection I noticed
wear on the brake caliper. The aft, upper, outer corner of the
caliper had a bright wear mark and a significant amount of the caliper
corner had been worn away. The was also wear on the upper caliper
bolt head and the safety wire that secures the caliper bolts had been
worn through. I found that when the gear was in the retracted position
the flexible brake pipe was in contact with the corner of the caliper.
When the gear was retracted or extended the steel braid of the brake
line was rubbing on the softer caliper and wearing it away. There was
no visible damage to the brake line. My temporary solution was to
wrap the brake line in a plastic spiral wrapping as used to contain
electrical cable harness or looms.

I inspected two other ASW 28 at my club. One with a slightly later
serial than mine showed caliper wear, another earlier serial number
had no wear. Two ASW 27 were also checked and neither showed any
caliper wear.

I suggest that all ASW 28 owners should check for this problem. If
uncorrected it could wear the caliper to the point that it would
require replacement. It seems possible that it could also cause a
failure of the brake line.

Andy