[Vwdiesel] knocking front wheel-huh?

[Mike & Coreen Smith]

Had a wicked thump/knock in my front wheel the other night.  Thought the
wheel was going to fall off.  The CV joint has been tinging/rattling/pinging
a bit lately (last 10,000kms) so I thought maybe this was it.  Nope.
Anyways, it was SOOOO bad, I pulled over (from 20kms of highway driving) and
checked the lugnuts, as I literally thought I was going to lose a wheel; it
was that bad.

Test drove the car 2 days later and nothing. Zip, nada, zilch. Ran as smooth
as always !!??

What gives?

Bro-in-law (mechanic) thought maybe somehow caliper got stuck on, heating up
rotor and then it became warped and started to knock/bang/thrash about.
Once cooled,maybe  it straightened up and all is fine.

I'm at a loss.

Ideas?

Mike in N.B.