The hydraulic brake system used in the Ford Falcon XK relies on hydraulic pressure to apply braking force evenly to all wheels. Proper operation depends on correct brake fluid level, properly adjusted components and a sealed hydraulic system free from leaks or air contamination.
When brake trouble occurs, a systematic inspection should be performed to determine the cause before any major repair work is undertaken.
Preliminary Checks
Before diagnosing specific brake problems, perform the following preliminary inspections.
Check the brake fluid level in the master cylinder reservoir. If necessary, add heavy-duty brake fluid until the level is within approximately ½ inch of the top of the reservoir.
Press the brake pedal firmly while the vehicle is stationary. If the pedal can be depressed more than halfway between its released position and the floor, the brakes require adjustment.
Apply steady pressure to the brake pedal and observe its movement. If the pedal slowly moves toward the floor, inspect the hydraulic system for fluid leaks.
If the brake pedal feels spongy, the hydraulic system should be bled to remove air from the brake lines and cylinders.
Brake Trouble Symptoms and Causes
Various brake symptoms may appear depending on the nature of the fault. Common symptoms include:
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One brake dragging
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All brakes dragging
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Hard brake pedal
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Spongy pedal feel
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Vehicle pulling to one side during braking
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One wheel locking
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Brake chatter
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Excessive brake pedal travel
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Brake pedal gradually moving to the floor
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Uneven braking
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Low brake pedal reserve
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Noisy or grabbing brakes
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Brakes failing to apply properly
These symptoms can be caused by faults in the hydraulic system, brake linkage, brake drums, linings or wheel cylinders.
Common Causes of Brake Problems
Pedal Improperly Adjusted
Incorrect brake pedal adjustment can lead to dragging brakes or excessive pedal travel.
Damaged Linkage
Bent or damaged brake linkage components can interfere with proper brake operation.
Restricted Brake Line
A restriction in the brake line can prevent proper hydraulic pressure distribution to the wheel cylinders.
Insufficient Brake Fluid or Leaks
Leaks within the hydraulic system or insufficient fluid in the master cylinder reservoir may cause loss of braking efficiency or excessive pedal travel.
Improper Tyre Pressure
Incorrect tyre pressure can affect braking stability and may cause the vehicle to pull during braking.
Improperly Adjusted or Worn Wheel Bearings
Loose or improperly adjusted wheel bearings can contribute to brake drag and uneven braking.
Distorted or Improperly Adjusted Brake Shoes
Brake shoes that are worn, distorted or incorrectly adjusted can cause brake chatter, uneven braking or poor braking efficiency.
Faulty Retracting Spring
Weak or broken brake shoe retracting springs may allow the brakes to drag after the pedal is released.
Brake Drum Out of Round
A brake drum that is not perfectly round can produce brake pulsation or chatter.
Worn or Glazed Brake Linings
Glazed or worn brake linings reduce friction and may cause noise, grabbing or poor braking performance.
Oil or Grease on Brake Linings
Contaminated brake linings can cause grabbing, uneven braking or reduced braking effectiveness.
Loose Carrier Plate
A loose brake backing plate may allow components to move during braking.
Loose Brake Linings
Brake linings that are not securely attached to the shoe may produce noise or vibration.
Scored Brake Drum
A scored drum surface can reduce braking efficiency and cause noise or vibration.
Dirt on Drum-Lining Surface
Dirt or debris between the drum and lining surfaces can cause uneven braking.
Faulty Brake Cylinder
A defective wheel cylinder may cause uneven braking or fluid leakage.
Dirty Brake Fluid
Contaminated brake fluid can reduce hydraulic efficiency and damage internal components.
Faulty Master Cylinder
A defective master cylinder may cause low hydraulic pressure or brake pedal sinking.
Air in Hydraulic System
Air trapped in the brake lines will cause a soft or spongy brake pedal and reduced braking effectiveness.
Road Test Checks
If the braking system appears safe for operation, a road test can help confirm the nature of the problem.
Apply the brakes at approximately 25–30 mph to check whether the vehicle stops in a straight line.
High-speed panic stops are not required to diagnose brake pull.
If the vehicle pulls to one side during braking, inspect and adjust the brakes to correct the imbalance.
Apply the brakes firmly without locking the wheels at approximately 50 mph to check for brake pedal chatter or surge. This condition is often caused by a brake drum that is out of round.
If a brake becomes locked and the vehicle must be moved, the wheel cylinder bleeder screw can be opened briefly to release a small amount of brake fluid. This may temporarily release the brake, but the underlying problem must still be corrected.
Proper inspection and diagnosis will ensure safe brake operation and prevent unnecessary replacement of components.
Safety, Copyright and Source Notice
Safety Disclaimer
Working on motor vehicles involves mechanical, electrical and chemical hazards. Always ensure the vehicle is safely supported, the engine is switched off when appropriate, and suitable safety equipment such as gloves and eye protection are used. If you are unsure about any repair or maintenance procedure, consult a qualified mechanic before attempting the work.
Source
Information compiled from period factory service literature.
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