passenger side tire squeak

is it a constant squeak or does it only happen when you hit a bump?It could be a wheel bearing but it seems rather odd for a bearing to start failing with only 70k+ miles.

Did you replace the ball joints because of the squeak...or did you start hearing the squeak after the ball joints were replaced?

I hate to tell you this but it sounds to me like Firestone took you for a ride.Seriously.They said it was your ball joints? Replaced them then you still had the squeak afterwards? Hmm..Doesn't sound right.This is why I do ALL of the work to my cars.

Anyway,jack the car up and place it on jack stands.First,check the passenger wheel for play.Get directly in front of it and grab it with both arms from the left side and the right side.Try to move it back and forth (like you are trying to steer the wheel).You shouldn't have any play in it except from what the steering gear allows.Now,take the passenger wheel off. Check the caliper mounting bolts that secure it to the spindle (Anchor plate bolts).These are the 2 bolts that are on the back side of the caliper.They are either torx T-45/T-50 (inverse star shaped) or a solid bolt (usually 17 or 18mm socket).If these bolts are loose even the slightest,then you'll have a squeak or rattle hitting bumps which would stop occuring when the brake is applied.Stepping on the brake compresses the pads against the rotor which would keep it from moving or rattling.Even if they dont feel loose with your hand,get a torx or socket and check.They should be very tight (60 - 80 ft-lbs).Also check the main caliper bolt (should be around 50 - 60 ft-lbs).If you dont have a torque wrench then just tighten them and apply a little extra force in a quarter turn.

Now would be a good time to check your pads and rotors while your down there.Check your tie-rod ends for excess play (moves too easily) or badly damaged dust boots.Check sway bar end link bushings for cracks or tears...etc etc.Just do an inspection if you havn't done one yet.Nows a good time to get to understand your car much better so some shop cant take a run for your money later on.