daytripper knastet inn: :
>> Audi A3 (2003) - after about 10 minutes of driving one of the wheels starts
>> to give a metalic squeeling sound intermittantly up to about 30mph. When
>> applying the brakes of any pressure the sound disappears. If (when
>> stationary) I press really hard on the brakes the intermittant squeeling
>> sound seems to disappear for a bit longer. Occurs regardless of
>> weather/temperature.
> Could be a bad caliper (or, a caliper gunked up with corrosion and road crap),
> could be air in the brake line to the offending corner...I suppose even a
> balky master cylinder might cause something like this.
My guess, air or [too much] water in the break line. Bleed all caliphers,
back wheels first, until brake fluid is clean/new (why not, change all
of it). In any case, this is a cheap & fast method before looking into
other factors.
Air can also be caused by (once) overheatet brake fluid, sloppy bleeding,
or broken/old seals in the calipher - if last, a renewal/overhaul kit
would be smart[tm] and rather cheap.
---
Might also be the (not anymore) sliding bolts on the back calipher(s),
shown by unsymmetrical worn brake pads. Quite common Audi thing ...