Replace the caliper, it is probably stuck. Take the brake pads off and check the wear pattern. If you are unable to tell take them to the autoparts store, they should be able to help.
if its the hub it self then its a axle change.
lift tailgate and look for two screws and remove them, and then turn the bulb housing right and oull out
You first must be assured that the brake pads and discs are not in need of replacement.
check the fuses,if it has currents,,and still don't work, then replace the cigarret coil lighter that you use to light up the cigarrete with
if you can manually move it with you hands them u need to tighten the nut on the arm
If it is a Toyota, they do not know how to fix the squeaking brakes either. Even after replacing all the pads and machining the rotors and rear drums
how do you fix brakes on a 2002 Cl 500 Benz
busted oil pressure sensor or oil level is already low - add more engine oil. try to fix the leak if the oil drips on a fast rate.
Change the brake pads. I have had good luck with PBR Deluxe and PBR Metalmaster. They are quieter and dust a lot less.
Try and get someone to read the ECU codes, that will tell you if the problem is from the "Knock Sensor". If it is you will need to buy a new one and replace it. They are very expensive and can only be got from a Toyota Dealer. To fit your self Drill a hole under the front seat(Directly above the sensor) and replace from there. If you dont want to drill a hole you will have to drop the engine and that is not a cheap option on a previa.
I am working on this myself right now. I have replaced the master cylinder, lines, shoes, and calipers. The problem persists. I am going to try sanding and lubing the ways on the calipers today. There is nothing else to fix. I found an article in a Dodge forum that suggested this in the most detailed fix i have found.
if u take off the egr valve and tap it it on something to knock out the carbon built up inside ,and put it back on, its a free fix,just the labor involved