Right Front Brake Drag After Pad Replacement
A 2015 SUV with 88,000 miles had front pads and rotors replaced 2,000 miles ago. The owner reports a pull to the right when braking and a burning smell after highway driving. After a 10-mile drive with light braking, the right front rotor is 340°F and the left front is 160°F. The right wheel is hard to turn by hand when hot, but both spin freely when cold. The right front inner pad is worn 2 mm more than the outer pad. The rotor has a blue tint. Guide pins were lubricated at the last service. The brake hose shows no external cracks. Fluid is dark and the last flush is unknown. The pedal is firm and ABS has no DTCs.
1. Interpret the temperature split and pad wear pattern. What does this tell you about the location and nature of the drag?
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The 180°F temperature split after a light-braking drive is too large to be normal heat soak; it localizes the drag to the right front corner. The inner pad wearing 2 mm more than the outer pad points toward the piston side of the caliper rather than a guide-pin problem, because a sticking guide pin usually loads the outer or leading edge. The blue rotor tint confirms excessive heat. However, the temperature and wear pattern do not by themselves separate a seized caliper piston from an internally collapsed brake hose. Both can hold pressure on the caliper. The dark fluid and unknown flush history also raise the possibility of contaminated fluid causing swollen seals. The next test must determine whether pressure is trapped at the caliper or upstream.
2. Describe a crack-open test at the right front caliper bleeder and explain how the result changes your repair decision.
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With the wheel hot and dragging, open the right front caliper bleeder just long enough to release pressure, then try to turn the wheel. If the wheel frees up and the temperature stops climbing, the caliper is holding pressure because of an upstream restriction, most likely a collapsed hose or a blocked ABS/hard line. If the wheel remains tight after the bleeder is opened, the caliper piston or slide is seized. Because the hose has no visible cracks, an internal collapse is still possible; a hose can fail internally without external evidence. On this vehicle, a caliper or hose replacement plus a full fluid flush is indicated if the test confirms drag. I would not replace the caliper without doing the crack-open test, because replacing the wrong part leaves the hose restriction in place.
3. The shop proposes replacing only the pads and rotors again. Why is that likely to return, and what else must be done?
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Replacing pads and rotors again treats the symptom, not the cause. The right front corner has already been overheated; new friction material will simply be cooked again if the caliper or hose continues to drag. The rotor may be warped or have uneven deposits from the heat, so machining or replacement may be needed, but only after the drag is corrected. The repair order should include the crack-open result, replacement of the failed caliper or hose, a complete fluid flush, and a road-test temperature check with an infrared thermometer. I would also inspect the opposite side and check for ABS DTCs. If the customer declines the root-cause repair, I would document that the new pads and rotors are not warranted against heat damage.