If I had to choose a "first" it would be the front brake calipers, since you
don't indicate anything has been done with the brakes that would cause this.
In addition, if the car pulls to one side when you brake, be especially
suspicious of the opposite side caliper. A quick check would be to raise the
front wheels, either both together or one at a time, and have somebody step
on the brake gradually until it goes all the way down. If either or both
wheels turn freely, continue to remove the wheel and caliper. (The following
may vary with brake manufacturer.) You will probably find the pads rattling
loose rather than being held against the rotor when you remove the caliper.
Remove the bolt that holds the two parts, then remove the sleeve that goes
over the bolt. You may have to drive it out of the caliper housing with a
soft faced mallet... that is what goes wrong. Clean and lubricate that
sleeve and the housing where it fits with disk brake grease, then reassemble
and make sure the sleeve isn't binding. Put it together and check the other
side. Unless the wheel becomes very difficult to turn when your assistant
begins to press on the brakes (like it should), I recommend you do the clean
and lubricate thing. It is an easy alternative to frustrating brake
problems.

The rear brakes (at least on my car - I think it applies to all variations)
don't have a floating caliper so are not susceptible to this problem.

If that doesn't fix the brakes and it has been 100K miles or more since the
last master cylinder overhaul, I recommend going ahead with that. Same
philosophy - a moderate cost for a likely suspect that needs periodic
attention anyway.

Between those and bleeding if you overhaul or replace the master cylinder I
think you will be on the road again.

Mike

You need to bleed the air out of the Brake system

Harold

Bleed the air out of the system.