One problem related to brake disc caliper has been reported for the 2004 Toyota Sienna. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Toyota Sienna based on all problems reported for the 2004 Sienna.
The car is used on an occasional basis. 34,000 miles in four years. It has suffered corrosion buildup on the rotors, so we have tried to use it at least twice a week, knowing that catastrophe can occur when the vehicle is not used with some regularity--especially in the cold weather. About two months ago, my wife complained of noise, and I told her it was due to corrosion buildup and that driving would remove the corrosion. Then she abandoned the car a couple of days later when the brakes failed. The inner pad had work down to metal, and the metal backing slid out of place. My wife wound up braking on the caliper piston. I will replace the brake shoes and rotors, and must also replace a caliper if I cannot find the piston as a separate piece. Estimate: $300, not counting the caliper, with me doing all the work. Toyota would likely charge a little more than $1,000 for the job. The car has sat unused and unrepaired now for weeks for want of the cash for the parts.