This procedure replaces the brake proportioning valve, which regulates hydraulic pressure between front and rear brakes to ensure proper braking balance and prevent premature rear wheel lockup.

Warnings

Tools required

Parts

• Brake proportioning valve assembly × 1 — Use OEM Toyota specification
• Brake line copper washers/gaskets × 4 — Usually included with valve
• Brake fluid × 1 — DOT 3

Fluids

• DOT 3 Brake Fluid — 1 qt

Preparation

1. Park vehicle on level surface and engage parking brake. Place wheel chocks behind rear wheels.
2. Open hood and locate brake proportioning valve on the firewall near the master cylinder.
3. Using turkey baster or fluid transfer pump, remove as much brake fluid as possible from master cylinder reservoir to minimize spillage.
4. Place absorbent pads or shop towels under the proportioning valve area to catch brake fluid.
5. Prepare brake line plugs or vacuum caps to seal open lines immediately after disconnection.
6. Have new proportioning valve and copper washers ready for installation.
7. Spray all brake line fittings at the proportioning valve with penetrating oil and allow to soak for 10-15 minutes.

Procedure

1. 1

   Label and photograph brake line connections
   Before disconnecting anything, take clear photos of all brake line connections to the proportioning valve from multiple angles. Use masking tape to label each brake line with its position (front left, front right, rear, etc.). The exact configuration varies by model year and ABS equipment, but typically there are 4-5 lines connected to the valve.
2. 2

   Disconnect first brake line
   Using the appropriate size flare nut wrench (typically 10mm), carefully loosen the first brake line fitting at the proportioning valve. Hold the valve body steady with another wrench if necessary to prevent twisting the mounting. Once loose, unthread the fitting by hand and immediately plug the open line with a brake line plug or vacuum cap to prevent fluid loss and air entry. Allow fluid to drain into catch pan.
   ⚠Use only a flare nut wrench (6-point box wrench) to prevent rounding off the soft brass fittings. Do NOT use open-end wrenches or adjustable wrenches.
   Torque spec

   Brake Line Fittings15 Nm (11 lb-ft)
3. 3

   Disconnect remaining brake lines
   Repeat the disconnection process for all remaining brake lines connected to the proportioning valve. Work methodically, disconnecting one line at a time, plugging each immediately after removal. Keep track of which line came from which port using your photos and labels. Some brake fluid loss is normal.
   Torque spec

   Brake Line Fittings15 Nm (11 lb-ft)
4. 4

   Remove proportioning valve mounting bolts
   Once all brake lines are disconnected and plugged, locate the proportioning valve mounting bolts (typically 2 bolts securing it to a bracket on the firewall). Remove these bolts completely and carefully extract the valve assembly. Inspect the old valve and mounting area for corrosion or damage.
   Torque spec

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

   Prepare new proportioning valve
   Remove the new proportioning valve from packaging and verify it matches the old valve exactly in terms of port configuration and mounting points. Install new copper washers/gaskets on all ports as provided with the valve. Do not reuse old washers. Verify all ports are clean and free of debris.
6. 6

   Install new proportioning valve
   Position the new proportioning valve in the mounting location, ensuring proper orientation matches your reference photos. Start the mounting bolts by hand and verify alignment before tightening. Torque the mounting bolts to specification in an alternating pattern if multiple bolts are present.
   ⚠Verify the valve orientation matches the original installation. Incorrect orientation may result in improper brake operation.
   Torque spec

   Proportioning Valve Bolts15 Nm (11 lb-ft)
7. 7

   Connect brake lines to new valve
   Remove plugs from brake lines one at a time and connect each line to its correct port on the new proportioning valve, referencing your photos and labels. Start each fitting by hand to ensure proper thread engagement, then tighten with flare nut wrench to specification. Work methodically to ensure each line goes to the correct port.
   ⚠️Cross-threading brake line fittings will cause catastrophic brake failure. Ensure each fitting threads smoothly by hand before using wrench. If resistance is felt, stop and verify proper alignment.
   Torque spec

   Brake Line Fittings15 Nm (11 lb-ft)
8. 8

   Refill master cylinder reservoir
   Fill the master cylinder reservoir with fresh DOT 3 brake fluid to the MAX line. Keep the reservoir filled throughout the bleeding process to prevent air from entering the system through the master cylinder.
   ⚠Use only fresh DOT 3 brake fluid from a sealed container. Never mix different brake fluid types or reuse old fluid.
9. 9

   Bleed brake system - rear brakes first
   Begin bleeding at the right rear wheel, then left rear. Have helper pump brake pedal 3-5 times and hold pressure. Open bleeder screw with 10mm wrench until fluid flows, then close before pedal reaches floor. Repeat until fluid runs clear without air bubbles. Keep master cylinder filled. Torque bleeder screws to specification after bleeding each wheel.
   ⚠️Never let the brake pedal go to the floor while bleeder is open, and never allow master cylinder to run dry. Either condition will introduce air and require complete re-bleeding.
   Torque spec

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

    Bleed brake system - front brakes
    Continue bleeding process at right front wheel, then left front wheel, using the same procedure as rear brakes. The standard bleeding sequence is: RR, LR, RF, LF (furthest to closest from master cylinder). After all wheels are bled, pump brake pedal firmly and verify solid, consistent pedal feel with no sponginess.
    ⚠️A spongy or soft brake pedal indicates air remains in the system. Do NOT drive the vehicle until pedal is firm and consistent.
    Torque spec

    Bleeder Screw13 Nm (10 lb-ft)
11. 11

    Inspect all connections for leaks
    With brake system bled, have helper apply firm, sustained pressure to brake pedal (approximately 50 lbs force) while you carefully inspect every brake line connection at the proportioning valve for any signs of leakage. Check mounting bolts, all line fittings, and the valve body itself. No leakage of any kind is acceptable.
    ⚠️Any brake fluid leak, no matter how small, is a critical safety failure. The vehicle must not be driven until all leaks are eliminated.

Reassembly

1. Top off master cylinder reservoir to MAX line with fresh DOT 3 brake fluid.
2. Clean any spilled brake fluid from painted surfaces, hoses, and components using water and shop towels.
3. Double-check all brake line fittings are torqued to specification and all bleeder screws are closed and torqued.
4. Verify proportioning valve mounting bolts are torqued to specification.

Verification

• Start engine and pump brake pedal multiple times. Pedal should be firm and consistent with approximately 1-2 inches of travel before resistance. No sponginess should be present.
• With engine running, apply firm brake pressure and hold for 30 seconds. Pedal should not sink or feel soft. If pedal sinks, air remains in system or there is a leak.
• Inspect all connections at proportioning valve one final time with brake pressure applied. No leakage is acceptable.
• Test drive vehicle in safe, controlled area at low speed (under 15 mph initially). Test brakes gently, then progressively harder. Braking should be smooth and balanced with no pulling to either side.
• Perform several moderate stops from 30-40 mph in a safe area. Verify no premature rear wheel lockup occurs and braking feels balanced front-to-rear.
• After test drive, re-inspect all proportioning valve connections for any signs of weeping or leakage. Check master cylinder fluid level.
• CRITICAL: If ANY abnormality is detected in brake feel, balance, or performance, do NOT continue driving. Have vehicle towed to professional service immediately.

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