This procedure covers the removal and replacement of the brake proportioning valve on a 2015 Kia Forte 1.8L, including proper bleeding of the brake system to ensure safe operation.

Warnings

Tools required

Parts

• Brake proportioning valve assembly × 1 — Use OEM Kia specification
• Brake line sealing washers (if applicable) × 4 — Use OEM specification

Fluids

• DOT 4 Brake Fluid — 1 qt

Preparation

1. Park vehicle on level surface and engage parking brake firmly
2. Chock rear wheels to prevent vehicle movement
3. Open hood and locate brake fluid reservoir - do NOT open yet
4. Place protective covers over fenders to prevent brake fluid damage to paint
5. Gather all tools and new parts before beginning work
6. Ensure you have at least 1 quart of fresh DOT 4 brake fluid available
7. Locate the proportioning valve - it is mounted on the firewall or frame rail near the master cylinder with multiple brake lines connected
8. Take photos of brake line routing and connections for reference during reassembly

Procedure

1. 1

   Prepare brake fluid reservoir
   Using a turkey baster or fluid transfer pump, remove brake fluid from the master cylinder reservoir down to the MIN line. This minimizes fluid loss when disconnecting lines. Dispose of old brake fluid properly - do not reuse. Keep reservoir cap loosely in place to prevent contamination.
   ⚠Dispose of brake fluid according to local environmental regulations. Do not pour down drains.
2. 2

   Label and photograph brake line connections
   The proportioning valve will have 4 brake lines connected (2 inlet lines from master cylinder, 2 outlet lines to rear brakes). Clearly label each line with tape marked 'LF' (left front inlet), 'RF' (right front inlet), 'LR' (left rear outlet), 'RR' (right rear outlet) or according to your photos. Note any specific orientation markings on the valve body.
3. 3

   Disconnect brake lines from proportioning valve
   Using the appropriate size flare nut wrench (typically 10mm or 12mm), carefully loosen each brake line fitting at the proportioning valve. Work slowly to avoid rounding off the soft brass fittings. Have a catch pan ready as brake fluid will drain from the lines. Once loosened, unthread fittings by hand and immediately cap or plug open lines with rubber caps to prevent fluid loss and contamination. Keep lines elevated if possible.
   ⚠️Use only flare nut wrenches on brake line fittings. Standard open-end wrenches will round off the soft fittings and cause leaks.
   ⚠Brake lines are under slight residual pressure. Have rags ready to catch dripping fluid.
4. 4

   Remove proportioning valve mounting hardware
   Locate the mounting bolts securing the proportioning valve to the mounting bracket or firewall. Remove these bolts using the appropriate socket. Support the valve as you remove the final bolt to prevent it from falling and damaging brake lines.
   ℹ️Some proportioning valves are mounted on a bracket. Note the orientation and position for correct reinstallation.
   Torque spec

   Proportioning Valve Bolts15 Nm (11 lb-ft)
5. 5

   Remove old proportioning valve
   Carefully remove the proportioning valve from the vehicle, keeping it upright to minimize fluid spillage. Inspect the mounting area for corrosion or damage. Clean the mounting surface with a wire brush if necessary. Inspect all brake line ends for damage, corrosion, or flaring issues - replace any damaged lines before proceeding.
6. 6

   Prepare and install new proportioning valve
   Remove the new proportioning valve from packaging. Verify it matches the old valve exactly in terms of port configuration and mounting. If the valve has protective caps on the ports, remove them just before installation. Position the new valve in the mounting location, ensuring proper orientation matches your photos. Thread mounting bolts by hand first to ensure proper alignment.
   ⚠Verify the replacement valve is the correct part for your specific vehicle. Using an incorrect valve will result in improper brake bias and dangerous braking performance.
7. 7

   Torque proportioning valve mounting bolts
   Tighten the proportioning valve mounting bolts to specification in a crossing pattern if multiple bolts are present. Ensure the valve is seated properly and positioned correctly before final torquing.
   Torque spec

   Proportioning Valve Bolts15 Nm (11 lb-ft)
8. 8

   Reconnect brake lines to proportioning valve
   Remove caps from brake lines. Inspect line ends and valve ports for any debris - blow out with compressed air if available. If your valve uses sealing washers at the fittings, install new washers now. Thread each brake line fitting into the correct port by hand, ensuring lines follow their original routing. Verify you are connecting each line to the correct port using your labels and photos. Hand-tighten each fitting until it seats against the valve body.
   ⚠️Cross-threading brake line fittings will cause catastrophic brake fluid leaks and brake failure. Thread fittings by hand first and ensure they turn smoothly.
9. 9

   Torque brake line fittings
   Using a flare nut wrench and torque wrench, tighten each brake line fitting to specification. Do not overtighten as this can damage the soft brass fittings and cause leaks. Verify each connection is snug and properly seated.
   ⚠Over-torquing brake line fittings can strip threads or crack fittings, causing brake fluid leaks.
   Torque spec

   Brake Line Fittings15 Nm (11 lb-ft)
10. 10

    Fill brake fluid reservoir
    Remove the master cylinder reservoir cap. Fill reservoir with fresh DOT 4 brake fluid to the MAX line. Keep the reservoir at least half full throughout the entire bleeding process. Have extra fluid ready.
11. 11

    Bleed brake system - rear brakes first
    Bleed the brake system starting with the wheel furthest from the master cylinder (typically right rear, then left rear, then right front, then left front - verify sequence in service manual). At each wheel, locate the bleeder screw on the brake caliper or wheel cylinder. Attach clear tubing to the bleeder screw and submerge the other end in a container with clean brake fluid. Have an assistant pump the brake pedal 3-4 times and hold pressure. Open the bleeder screw 1/2 turn - fluid and air bubbles will flow out. Close bleeder screw before pedal reaches floor. Repeat until no air bubbles appear and only clean fluid flows. Tighten bleeder screw to specification. Maintain reservoir level throughout process.
    ⚠️Never allow brake fluid reservoir to run dry during bleeding or air will enter the master cylinder, requiring master cylinder bleeding.
    ⚠The brake pedal will go to the floor during bleeding. This is normal. Warn your assistant not to release the pedal while bleeder screw is open.
    Torque spec

    Bleeder Screw13 Nm (10 lb-ft)
12. 12

    Final brake fluid level check
    After bleeding all four wheels, check the brake fluid reservoir and fill to the MAX line with fresh DOT 4 brake fluid. Wipe any spilled fluid from the master cylinder area. Securely install the reservoir cap.
13. 13

    Inspect for leaks
    With the engine off, pump the brake pedal firmly 10-15 times to build pressure in the system. Inspect all brake line connections at the proportioning valve for any signs of leakage. Also check all bleeder screws. Wipe all connections dry with a clean rag, then pump pedal again and recheck. Any fluid seepage indicates a connection that must be tightened or repaired before proceeding.
    ⚠️Even small brake fluid leaks can cause complete brake failure. Do not proceed if any leaks are present.

Reassembly

1. Double-check all brake line connections are properly torqued and leak-free
2. Verify brake fluid reservoir is at MAX line with fresh DOT 4 fluid
3. Ensure no tools or parts are left in the engine compartment
4. Remove fender covers and clean any brake fluid spills immediately with water

Verification

• With engine off, pump brake pedal 20-30 times - pedal should become firm and hold pressure without sinking
• Start engine (power brakes will assist) - pedal should drop slightly then remain firm
• With engine running, apply firm steady pressure to brake pedal for 30 seconds - pedal should not sink
• Perform a low-speed brake test in a safe area - brakes should apply evenly without pulling to either side
• Test drive at speeds up to 25 mph in a safe area, performing multiple gentle and moderate stops - verify proper brake function and no warning lights
• After test drive, re-inspect all proportioning valve connections for leaks while system is at operating temperature
• Final verification: Perform a more aggressive stop from 35-40 mph in a safe area - brakes should function smoothly without pulling, pulsing, or requiring excessive pedal effort
• If ANY abnormal brake behavior is detected (soft pedal, pulling, warning lights, leaks), DO NOT DRIVE THE VEHICLE - repeat bleeding procedure or seek professional service immediately

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