Q: All four brakes locking up after being driven for about 45 minutes

Hi there, if work was recently done on the master cylinder or brake booster, check to see if the brake push rod (manual or power assisted) has too little free play. If it is too tight, the master cylinder piston could be partially blocking the return port. If the brake fluid reservoir is too full, this can cause hydraulic brake drag. A weak or failed metering valve - a valve intended to keep a small amount of pressure on the front disk brakes only, could be causing a small amount of pressure on all of the brakes temporarily as you are experiencing. I would recommend having an inspection done on your dragging brakes by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.