Brake Caliper Rebuild - Rear

This procedure covers disassembly, cleaning, inspection, seal replacement, and reassembly of the rear brake calipers on a 2015 Kia Forte with 1.8L engine to restore proper caliper function and prevent brake fluid leaks.

Warnings

Tools required

Parts

• Rear brake caliper rebuild kit (includes piston seals, dust boots, bleeder caps) × 2 — Use OEM specification for 2015 Forte rear caliper
• Brake caliper slide pin grease (silicone-based) × 1 — High-temperature silicone brake grease
• Caliper slide pin boots (if damaged) × 2 — Included in some rebuild kits or sold separately

Fluids

• DOT 4 Brake Fluid — 1 qt

Preparation

1. Park vehicle on level, solid ground and engage parking brake firmly
2. Chock front wheels securely
3. Loosen rear wheel lug nuts 1/4 turn while vehicle is on ground
4. Raise rear of vehicle with floor jack and support securely on jack stands rated for vehicle weight
5. Remove rear wheels completely
6. Prepare clean workspace with drain pans, brake cleaner, and all rebuild kit components laid out
7. Verify rebuild kit contents match caliper type before beginning disassembly
8. Open brake fluid reservoir cap slightly to allow fluid displacement during piston retraction

Procedure

1. 1

   Remove caliper from bracket
   Attach a clear tube to the bleeder screw and place the other end in a brake fluid catch container. Loosen the bleeder screw slightly to relieve pressure, then close it. Remove the caliper slide pin bolts (lower and upper) using appropriate socket. Lift caliper off the brake rotor and bracket. Suspend caliper with wire or bungee cord - do NOT let it hang by the brake hose. If completely removing caliper, place a drain pan beneath the brake hose connection, then disconnect the banjo bolt from the caliper. Cap the brake line immediately to prevent fluid loss and contamination.
   Torque spec

   Caliper Slide Pin Bolts35 Nm (26 lb-ft)
2. 2

   Disassemble caliper and remove piston
   Place caliper in a clean drain pan with the piston facing upward. Remove the dust boot retaining ring if present using snap ring pliers or carefully pry out the dust boot. Cover the caliper body with a shop towel, leaving the piston exposed. Using controlled compressed air applied to the brake fluid inlet port, carefully blow the piston out of the caliper bore. Use LOW pressure and keep fingers clear - the piston will eject forcefully. If piston is stuck, tap gently around the caliper body with a rubber mallet while applying air pressure.
   ⚠️Piston will eject with significant force when using compressed air. Keep hands and face clear of the piston path. Start with low air pressure and increase gradually.
3. 3

   Remove old seals and inspect components
   Once piston is removed, use a plastic or wooden tool (never metal) to carefully pry out the piston seal from its groove inside the caliper bore. Remove any remaining dust boot material. Thoroughly inspect the caliper bore for scoring, corrosion, or pitting. Minor surface rust can be cleaned, but deep scoring or pitting requires caliper replacement. Inspect the piston surface for chrome plating damage, scoring, or corrosion. If piston surface is damaged, the piston must be replaced. Inspect caliper slide pins for wear, corrosion, or damage.
4. 4

   Clean all caliper components
   Clean the caliper bore, piston, and all internal passages thoroughly using brake cleaning solvent and lint-free cloths. Use a wire brush to clean the caliper slide pin bores in the bracket. DO NOT use petroleum-based solvents. Blow out all passages and bores with compressed air. Ensure the bleeder screw passage is clear. The caliper bore must be completely clean and dry before installing new seals. Clean the piston with brake cleaner and dry completely. Inspect again after cleaning to ensure no damage was missed.
5. 5

   Install new piston seal
   Remove the new piston seal from the rebuild kit. Lubricate the seal lightly with clean DOT 4 brake fluid. Carefully install the seal into the groove in the caliper bore, working it in evenly around the circumference. Ensure the seal is seated properly in its groove with no twists or folds. The seal must sit completely flat in the groove all the way around. Do not stretch or distort the seal excessively during installation.
6. 6

   Install piston and dust boot
   Lubricate the caliper bore and piston surface with clean DOT 4 brake fluid. Install the new dust boot onto the piston according to the rebuild kit instructions (some boots install on piston first, others on caliper bore first). Carefully align the piston and start it into the caliper bore by hand, ensuring it enters straight and does not cock to one side. Use a caliper piston tool or appropriately sized C-clamp to press the piston fully into the bore until it bottoms out. Ensure the dust boot seats properly in both the caliper groove and piston groove. Install the dust boot retaining ring if applicable.
7. 7

   Service caliper slide pins
   Remove the caliper slide pins from the bracket. Clean slide pins thoroughly with brake cleaner and inspect for wear, corrosion, or damage. Replace slide pins if damaged. Check slide pin boots for tears or deterioration and replace if necessary. Apply a thin, even coating of silicone brake grease to the slide pin shafts (not the threads). Install new slide pin boots if removed. Insert slide pins back into bracket bores and verify they slide freely without binding.
8. 8

   Reinstall caliper to vehicle
   If brake hose was disconnected, install new crush washers on the banjo bolt and reconnect the brake hose to the caliper. Tighten banjo bolt to specification (typically 18-23 Nm, though not provided in torque list - use moderate hand-tight pressure plus 1/4 turn). Position the caliper over the brake rotor and bracket. Apply a thin coating of silicone brake grease to the caliper slide pin bolt threads and under the bolt heads. Install and tighten the caliper slide pin bolts to specification using a torque wrench.
   Torque spec

   Caliper Slide Pin Bolts35 Nm (26 lb-ft)
9. 9

   Bleed brake system
   Attach a clear tube to the bleeder screw with the other end submerged in a container of clean DOT 4 brake fluid. Have an assistant pump the brake pedal 3-4 times and hold pressure, or use a vacuum bleeder. Open the bleeder screw 1/4 to 1/2 turn and allow fluid and air to flow out. Close the bleeder screw before releasing pedal pressure. Repeat until no air bubbles appear in the expelled fluid and only clean fluid flows. Tighten bleeder screw to specification. Check brake fluid reservoir frequently and maintain proper level throughout bleeding process. Never let reservoir run dry.
   ⚠If brake pedal was pressed to floor while caliper was removed or disconnected, the master cylinder may be damaged. Bleed carefully and check for proper pedal feel.
   Torque spec

   Bleeder Screw10 Nm (7 lb-ft)
10. 10

    Repeat for opposite side
    Repeat steps 1 through 9 for the opposite rear caliper. Both rear calipers must be rebuilt together to ensure balanced braking performance. After both calipers are rebuilt and bled, check brake fluid level in reservoir and top off to MAX line with fresh DOT 4 brake fluid. Install wheels and hand-tighten lug nuts in a star pattern.
11. 11

    Final torque and test
    Lower vehicle until wheels just touch ground but jack stands still support vehicle weight. Torque wheel lug nuts to specification in a star pattern using torque wrench. Remove jack stands and lower vehicle completely. Torque lug nuts again in star pattern to verify proper torque. Pump brake pedal slowly several times until firm resistance is felt - pedal should not go to floor. Check all brake connections for leaks. Test brake operation at low speed in a safe area before returning to normal driving.
    ⚠️Before driving, verify brake pedal is firm and brakes engage properly. If pedal feels soft or goes to floor, DO NOT DRIVE - repeat bleeding procedure or seek professional service immediately.
    Torque spec

    Wheel Lug Nuts140 Nm (103 lb-ft)

Reassembly

1. Ensure all caliper components are properly assembled with new seals from rebuild kit
2. Verify caliper slide pins move freely and are properly greased
3. Confirm brake hoses are not twisted or kinked
4. Top off brake fluid reservoir to MAX line with fresh DOT 4 fluid only
5. Dispose of old brake fluid properly - do not pour down drains or into environment

Verification

• Brake pedal should be firm with approximately 1-2 inches of free play before engagement when engine is running
• No brake fluid leaks visible at caliper, bleeder screw, or brake hose connections
• Parking brake holds vehicle on incline (rear brakes functional)
• Test brakes at low speed (under 15 mph) in safe area - vehicle should stop smoothly without pulling to either side
• Perform several moderate stops from 30-40 mph to seat brake pads and verify consistent braking performance
• Recheck brake fluid level after test drive - should be at MAX line
• Allow 200-300 miles for complete break-in of rebuilt calipers before full performance is achieved
• If any vibration, noise, pulling, or soft pedal occurs, stop driving immediately and re-inspect all work

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