One problem related to brake disc pads has been reported for the 2004 Toyota Highlander. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Toyota Highlander based on all problems reported for the 2004 Highlander.
Brought the vehicle in for a routine oil and filter replacement. As dealers normally do, they also did spot checks on brakes, hoses, etc. The two front wheels had been removed supposedly to check the wear on the brake pads. As the mechanic was reinstalling the wheels, two of the lugs broke off. The service rep showed me one as he explained why the oil and filter job was taking much longer than expected. I studied the fracture face and saw typical fatigue failure with origin and progression features. It was quite evident the problem started much earlier than today. I only saw one broken lug, but the service rep said that there were two lugs that broke prematurely when they were reinstalling one wheel. This concerns me so I am giving this information to NHTSA. I have taken close-up pictures of the fracture face if you would like them submitted. To be safe, I am having all the front wheel lugs replaced on this vehicle. Agreed, this isn't necessarily a Toyota problem. It could have been caused by overtorque when I had the tires replaced. If it is a Toyota problem, you'll have other reports similar to mine. (I am a retired sr. Quality engineer familiar with accident investigation, failure modes, metallurgy, metallography, machining practices, threads, etc. ).