CARspec had the opportunity to diagnose and repair a seized front caliper assembly. As this is a fairly common failure in Minnesota, we wanted to share the symptoms and repair procedure for the issue.
The owner of this 2004 Highlander was concerned over a brake pulsation and noise when driving. Upon inspection the technician, when removing the left front wheel, found the lug nuts too hot to touch. The rotors showed obvious signs of overheating once the wheel was removed. Here’s what the overheated rotor’s metal looked like:
Highlander Overheated Rotor
Similar to the seized calipers we wrote about on the GX470/4Runner, too much heat damages the rotor and results in an uneven surface. The dark spots are the cause of the guest’s pulsation and noise. Note the overheated rotor’s rust color is lighter than normal:
Highander Overheated Rust
This also indicates overheating. The root cause was the left front caliper’s hydraulic piston applying but failing to unapply – sticking on and holding the pad against the rotor (generating a lot of heat in the process). The left front caliper’s piston couldn’t be pushed back into the bore, condemning the assembly:
Seized Caliper
The result of the sticking piston were heavily worn brake pads on the sticking caliper. Here’s the left inner pad against the right inner:
Worn Pad Difference
The repair was to replace both front rotors, all pads, shim, and fitment kits, and the left front caliper. As Eden Prairie and Chanhassen’s Toyota and Lexus repair specialist we keep the majority of late model, Toyota genuine brake pads, shims, fitment kits and rotors in stock to quickly fix an issue like this. If you’ve got a brake issue (or want us to take a non-charge look at your brakes), give us a call at (952)426-4798 today!
