After my half hearted power wash in the local garage I decided to finish the job properly on my front diveway with my own power hose.Well I blasted the wheels and callipers for what must have been 15-25 minutes and the dreaded screech is gone I reckon .Brake feel has changed too , a slight hesitancy and then loads of positive feeling bite .This contrasts well with the previous over servoed pogo-ing and lunging back and forwards ...Im curious to take it out for a good spin but dont want to get it dirsty before I finish T Cutting or white spiriting the horrific tar spots and waxing it .
You need to be very careful because power hoses can be razor sharp ( I bled learning!)and you could damage brake lines or even tyres...

It seems strange that you used the power wash at the garage when you had one at home.

I'm sure the screech will be back soon :devil:
I power wash my wheels every week and it doesn't make a difference, although I would never aim the powerwasher directly at the brakes. Washing them can make it worse for a while because the discs rust and can then rub a bit until the rust wears off.

Don't use T-cut for tar. The best things far tar is probably either a tar remover (eg. AutoGlym) or detailing clay. I get so much that I usually end up using clay, but at the moment I don't think it's worth removing tar because my car seems to get covered within just a week.

Yeah Im v lazy where my power washer is concerned ...its buried in the shed and the hose takes ages to straighten out and it gets mud all over my lovely clean concrete driveway...Both my car and wife's Seat Altea XL's brakes are grinding like mad since the snow...presumably grit and sand under the pads...cant be good !