Front V Brake squealing on Trek FX 7.4 I know this is a frequent question in this forum...  To use a cliché &quot;I've tried A, I've tried B. what do I do now?&quot;...
I have a very persistent squealing from my front Tektro v brake, on my 5-yrs-old Trek Fx 7.4.  I've tried:

Cleaned the rim and pads , with isopropyl alcohol, then with brake cleaning fluid
Installed new pads, twice (two different brands)
&quot;Toed in&quot; the brake pads, tried more or less, even no, toe-in
Checked the wheels for true and play in the wheel's bearing (both OK)

... and no luck!  Front brake still shrieks like a banshee...  It seems like there is some play on the brake caliper... however on my wife's bike (similar model), there is some play but hers doesn't shriek at all.  What is the next step?  Should I replace the front brake set?  Try baby powder on rim?  Try cleaning the rim with fine steel wool?  Thanks for any help...
Since a single pair of V brakes is not much more than 2-3x the price of decent set of pads, why won't you try a different pair of V brakes? It's not hard to install, only bit more work as changing the pads. Also having some play on the brake arms is a cause for concern -- there shouldn't be any play in decent brakes apart from sidewards play against the spring due to the pad gap.
In one of my bikes, the front brake squealed like hell. It's not V brake but cantilever. I assume some combination of cantilever brake arms, rims, fork and pads caused the squeal. Changing the Kool Stop salmon pads to Shimano S70C pads fixed the squeal for me.