How to Troubleshoot a Toyota Brake Caliper
Toyota makes use of various types of brake caliper in its vehicles. There's the multiple, dual, and single piston designs as well as the fixed and sliding mount. Fixed-mount caliper has pistons on each side of the rotor, plus there's direct application by the moving pistons of the outboard and inboard pads. What's more, the more pistons are used on the caliper (the fixed mount has one or two pistons on each side), the applied pressure becomes more even. This is the reason multiple piston calipers are often used on heavy-duty vehicles and sports models. With that said, when troubleshooting your Toyota's brake caliper, you need to take into account what type of design and mounting variant it is.
Common fixed- and sliding-mount brake caliper problems
Fixed-mount calipers last longer but are costlier to repair, making them quite uncommon compared to the sliding mount brake caliper. This caliper variant only has one side of the rotor with pistons. It slides in order to apply the other pad. As such, when the slides seize, the outboard pad won't apply even if the inboard pad does.
If the slides bind, the outboard pad won't release when the brakes are activated, resulting in rapid pad wear and rotor complications. This might be because these slides require proper lubrication at every brake service since they alternate from one pad to another in contrast to the fixed mount that has pads on all sides. You also have to ensure that the protective boots that seal the slides are in good working order every time.
Avoid ending up with a caliper that applies only one pad
When your Toyota sliding mount brake caliper ends up seizing or binding, it tends to only apply one pad. This should be avoided at all costs or else, you'll end up shouldering all the costs of repair. More to the point, the brake rotor will warp, thanks to the pressure of applying only one pad and the heat produced from the excessive one-sided friction caused by such an event.
In fact, one of the major symptoms of caliper slide malfunction or impairment is when your brake pads wear down quickly yet in an uneven manner or if your brake rotors get warped and twisted altogether. As such, whenever these symptoms show up, your caliper slides should be immediately inspected and serviced before you end up with even bigger problems.
The many ways your brake caliper can fail
There are many other ways a brake caliper can fail other than seizing or binding. For example, your Toyota's piston can get stuck in the bore or the seal can get damaged, causing leaks that compromise your brake caliper's function. Replacement or rebuilding of the caliper is recommended when this happens. For calipers that make use of corrosion-resistant, noise-reducing phenolic pistons that isolate heat from the fluid, the piston's coating can wear down.
The piston will then swell and get stuck into the bore of the caliper, resulting in a great deal of heat, noise, and rapid pad wear. As for metal piston calipers, the same type of issues can come about. You can avoid corrosion and excessive wear by regular replacement of brake fluid. When your brake hoses fail, it's hard to detect. You'll have to get your Toyota serviced in a proactive manner to see if there are signs of deterioration on the hose material that can cause your piston to stick to your caliper bore.