The brake pedal travel was getting longer again, so either the brake de-airing didn't work or something else is going on.
I noticed the shims on the back of the front pads had moved again. They had done this in the previous video, but I didn't think much of it...

So this time I want to eliminate the shim slip as a possible cause, so I'm using a spray adhesive to glue them on.
I'm also using a "caliper twist" to de-air the brake lines... More effective?? perhaps.

Anyway the initial few test runs seem better. Pedal is firmer and the brakes more progressive with no sudden braking after initial application.
Here's the video

 

I don't know if the spray adhesive is going to hold up to the heat but only one way to find out.

 

So after 1 month, the brakes feel much better. Just a light touch needed now and quite progressive.
Now what fixed it???
Was it the way I twisted the caliper off after taking the sliding pin bolts out (compressing the piston & pushing air back into the reservoir)
OR
Was it the spray adhesive on the shims

 

Well, after 3 months, the glued shims seem to be working.
Brake pedal travel remains good.
Braking is easy and precise with no sponginess.
I'm calling it fixed.

 

6 month visual inspection. The right front outer is slipping despite the glue. Has not affected braking performance yet.