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Seized Brake Caliper: 7 Symptoms and How to Confirm It

A seized brake caliper does not just stop working — it works all the time. The pad stays pressed against the rotor, generating heat continuously. That makes it one of the few brake faults that can escalate quickly, and it produces a distinctive set of symptoms. 1. The Vehicle Pulls to One Side When Braking If one caliper is applying less force than its opposite number, the car pulls away from the weak side under braking. If a caliper is dragging constantly, the car may pull toward that side even without touching the brakes. Note the direction and whether it happens only while braking. That distinction narrows things down considerably. 2. One Wheel Runs Much Hotter Than the Others This is the clearest indicator. After a short drive without heavy braking, carefully check the temperature near each wheel — hold your hand close rather than touching, because a dragging brake can get hot enough to burn. A dragging caliper makes that corner dramatically hotter than the other three. In severe cases you will see the wheel discoloured, smell a hot metallic or burning odour, or even see smoke. 3. Uneven Pad Wear Pull the wheel and compare pads. Two patterns matter: Inner pad far more worn than outer: often a seized caliper piston. Outer pad far more worn than inner: often seized slide pins, so the caliper body cannot float back. One corner far more worn than the opposite corner: that side is dragging. 4. Reduced Fuel Economy and Loss of Power A dragging brake is a constant parasitic load. Noticeably worse fuel consumption with no other explanation, or a vehicle that feels like it is being held back, is worth investigating. 5. Grinding, Squealing or a Constant Rubbing Noise A caliper that never fully releases keeps the pad in light contact, producing a rubbing or grinding that continues while driving rather than only when braking. 6. A Spongy or Sinking Brake Pedal Overheated brake fluid can boil, introducing compressible vapour into the hydraulic system. The result is a pedal that feels soft or sinks toward the floor — usually after sustained braking or after a dragging brake has been generating heat. 7. The Vehicle Feels Sluggish From a Stop In advanced cases the drag is significant enough to be obvious. The car creeps reluctantly, and may feel like the parking brake is partially applied. What Actually Seizes The caliper piston. Corrosion in the bore, or a deteriorated dust boot letting in water and grit, causes the piston to stick. The slide pins. On floating calipers, the body slides on two pins. When the grease dries out or the boots tear, the pins seize and the caliper cannot centre itself. The brake hose. A hose can fail internally, acting as a one-way valve — pressure gets to the caliper but cannot return. This produces identical symptoms to a seized caliper, and replacing the caliper will not fix it. The parking brake mechanism, on rear calipers with an integrated parking brake, particularly if cables are corroded. How to Check Wheel spin test. With the vehicle safely supported and in neutral, spin each wheel by hand. Some light drag is normal. A wheel that stops almost immediately, or takes real effort to turn, is dragging. Piston retraction. With the pads out, try to compress the piston with a proper tool. A piston that will not retract, or moves unevenly, has seized. Slide pin check. Remove the pins. They should slide smoothly and be coated in clean grease. Dry, rusty or scored pins need attention. Hose test. If the caliper releases when you crack open the bleeder, the hydraulic pressure is not returning — suspect the hose rather than the caliper. Repair or Replace? Slide pins and their boots are routinely serviceable — clean them, replace damaged boots, and apply the correct high-temperature silicone grease. That solves a large share of caliper problems at minimal cost. A seized piston is a different matter. Rebuild kits exist, but if the bore is pitted with corrosion the rebuild will not last. On most vehicles a replacement caliper is the practical choice. Replace calipers in axle pairs. Mismatched braking force between left and right is a handling and safety problem. Common Misconceptions "New pads will fix the uneven wear." If the caliper is the cause, new pads wear unevenly too. "Pulling under braking is always alignment." Alignment pull is present all the time. Pull that appears only when braking is a brake fault. "It only drags a little, it can wait." Heat builds cumulatively. Dragging brakes have caused rotor damage, boiled fluid and wheel bearing failures. "Any grease works on slide pins." Petroleum-based grease swells the rubber boots and makes the problem worse. Use silicone-based brake grease. Before You Order a Replacement Calipers are side-specific and vary by brake package — the same model can use different calipers depending on trim, engine or rotor size. Check whether the bracket is included, whether it is front or rear, and confirm driver or passenger side. Match the fitment chart to your exact year, trim and brake configuration. Plan on new pads and a brake fluid bleed at the same time, and inspect the rotor — a dragging caliper often overheats and warps it.