Ford Transit Brake Pedal Problems

The braking system in any vehicle is paramount for safety, and for a workhorse like the Ford Transit, reliable stopping power is non-negotiable. Owners sometimes encounter a concerning issue where the brake pedal slowly sinks towards the bulkhead while applying pressure, a phenomenon often referred to as 'pedal creep'. This can be particularly alarming when braking from higher speeds, such as motorway driving. If you've experienced this, you're not alone, and it's crucial to understand why it might be happening and what steps to take.

Understanding Pedal Creep

Pedal creep is characterised by the brake pedal gradually depressing further into the footwell while maintaining consistent pressure. It's distinct from a spongy pedal, which typically indicates air in the brake lines. Pedal creep suggests a leak or a failure within the hydraulic system that allows fluid to bypass the intended pressure zone. The technician's comment that 'all diesel Transits do this' is highly questionable and likely inaccurate. While some older braking systems might exhibit minor pedal movement over extended periods, a noticeable and progressive sinking at motorway speeds points to a fault that requires investigation.

Common Causes of Pedal Creep

Several factors can contribute to a Ford Transit exhibiting pedal creep:

1. Brake Fluid Issues

Contaminated or Low Brake Fluid: Brake fluid is hygroscopic, meaning it absorbs moisture from the atmosphere over time. This contamination can lower its boiling point, leading to vapourisation under heavy braking and a spongy pedal. However, severe contamination or a very low fluid level (due to a leak) can also contribute to pedal creep. When the fluid level is low, air can be drawn into the system, or the master cylinder's seals may not be fully submerged, allowing fluid to pass. Replacing the fluid, as was done in the case mentioned, is a good starting point, but if the underlying issue isn't resolved, the problem will persist.

2. Master Cylinder Faults

Internal Seal Failure: The master cylinder is the heart of the hydraulic braking system. It converts the mechanical force from the brake pedal into hydraulic pressure. Inside the master cylinder are seals that prevent fluid from bypassing the pistons. If these seals become worn, damaged, or hardened, fluid can leak past them, allowing the pedal to sink. This is one of the most common causes of pedal creep. A failing master cylinder might also show signs of fluid leakage around its housing.

3. Brake System Leaks

External Leaks: Leaks can occur at various points in the hydraulic system, including the brake lines, flexible hoses, calliper seals, or wheel cylinder seals (on drum brakes). Even a small, slow leak can lead to a gradual loss of hydraulic pressure, manifesting as pedal creep. It's essential to visually inspect all brake components for any signs of fluid dampness or drips.

4. Brake Calliper or Wheel Cylinder Issues

Sticking Pistons: In disc brakes, the pistons within the brake callipers can sometimes become stuck due to corrosion or dirt. This can prevent the brake pads from fully retracting, leading to drag and potentially affecting pedal feel. More critically, a damaged seal on a calliper piston could allow fluid to bypass it, causing pedal creep. Similarly, in drum brake systems, faulty wheel cylinders can exhibit similar issues.

5. ABS Modulator Issues

While less common as a cause of simple pedal creep, a malfunctioning Anti-lock Braking System (ABS) modulator or its seals could, in some rare instances, contribute to hydraulic pressure loss. However, this is usually accompanied by ABS warning lights or other related symptoms.

Troubleshooting and Diagnosis

Diagnosing pedal creep requires a systematic approach:

Step 1: Visual Inspection

Begin with a thorough visual inspection of the entire braking system. Check the brake fluid level in the reservoir. Look for any signs of leaks around the master cylinder, brake lines, hoses, callipers, and wheel cylinders. Pay close attention to the condition of the flexible brake hoses, as these can degrade over time and develop small leaks or bulges.

Step 2: Check Brake Fluid

Ensure the brake fluid is clean and at the correct level. If it appears dark, murky, or contains debris, it should be flushed and replaced with the correct type of fluid (refer to your Transit's owner manual for the specified DOT rating). After replacing the fluid, the system will need to be bled.

Step 3: Brake Bleeding Procedure (General Guide for Transit Connect 2011)

Note:** This is a general guide. Always consult your specific vehicle's service manual for the precise procedure. The order of bleeding is critical to effectively remove air from the system. Typically, you start with the wheel furthest from the master cylinder and work your way closer.

Tools and Materials:

• Correct type of brake fluid
• Wrench to fit bleed nipples
• Clear plastic tubing
• Collection container
• An assistant (highly recommended)
• Safety glasses and gloves

Procedure:

1. Locate the Master Cylinder: Identify the brake fluid reservoir under the bonnet.
2. Determine Bleeding Order: For most vehicles, the order is passenger rear, driver's rear, passenger front, driver's front. For a 2011 Transit Connect, if the master cylinder is on the driver's side under the bonnet, the standard procedure is to start with the passenger rear wheel.
3. Prepare the Bleeder Screw: Clean the bleeder screw at the furthest wheel cylinder or calliper. Attach a clear plastic tube to the bleeder screw, ensuring a snug fit. Place the other end of the tube into a collection container.
4. Pressurise the System: Have your assistant press the brake pedal firmly and hold it down.
5. Open the Bleeder Screw: Carefully open the bleeder screw a quarter to half a turn. Brake fluid and any trapped air will flow through the tube into the collection container.
6. Close the Bleeder Screw: Once the fluid flow stops, or just before the pedal reaches the floor, close the bleeder screw tightly.
7. Release the Pedal: Instruct your assistant to release the brake pedal slowly.
8. Top Up Fluid: Check the brake fluid level in the reservoir and top it up as needed. Never let the reservoir run dry, as this will introduce more air into the system.
9. Repeat: Continue this process for each wheel, moving progressively closer to the master cylinder. Bleed each brake until no air bubbles are seen in the fluid and the fluid runs clear.
10. Final Check: Once all wheels are bled, ensure the bleeder screws are tight and the fluid level is correct. Test the brake pedal; it should feel firm and not sink.

Step 4: Master Cylinder Test

If bleeding doesn't resolve the issue, the master cylinder is the next suspect. A common test is to bleed the system thoroughly, then close all bleeders. With the engine off, pump the brake pedal several times. The pedal should become firm. Then, apply steady pressure to the pedal. If the pedal slowly sinks to the floor, it strongly indicates an internal leak in the master cylinder.

Step 5: Check Callipers and Hoses

If the master cylinder appears to be functioning correctly, investigate the brake callipers and flexible hoses. A sticking calliper piston or a faulty seal can cause fluid bypass. Inspect the flexible hoses for any signs of cracking, swelling, or leakage, especially near the ends where they connect to the callipers or hard lines.

When to Seek Professional Help

Brake issues can be complex and dangerous. If you're not comfortable performing these checks or if the problem persists after initial troubleshooting, it's highly recommended to consult a qualified mechanic. They have the specialised tools and expertise to accurately diagnose and repair brake system faults, ensuring your Ford Transit remains safe to drive.

Frequently Asked Questions

Q1: My brake pedal sinks slowly when I hold it down. What's the most likely cause?

A1: The most common causes for a slowly sinking brake pedal are internal leaks within the master cylinder or external leaks in the brake lines, hoses, or at the callipers/wheel cylinders.

Q2: The Ford technician said this is normal for diesel Transits. Is this true?

A2: No, this is highly unlikely to be normal behaviour. While some minor pedal movement might occur in older systems over long periods, a noticeable sinking pedal, especially at speed, indicates a fault that needs to be addressed.

Q3: How important is the order of bleeding the brakes?

A3: The bleeding order is crucial for effectively removing air. Starting furthest from the master cylinder and working closer ensures that any air is pushed towards the open bleeder, rather than being trapped further in the system.

Q4: Can I use a vacuum bleeder for my Transit?

A4: Vacuum bleeders can be effective, but care must be taken not to introduce air into the system through the bleeder screw threads if the seal isn't perfect. Pressure bleeding or the traditional two-person method are often preferred for ensuring thorough bleeding.

Q5: How often should I change my brake fluid?

A5: It's generally recommended to change brake fluid every two years or as per the vehicle manufacturer's service schedule. This is because brake fluid absorbs moisture, which can lead to corrosion and reduced braking performance.

Maintaining your Ford Transit's braking system is vital. If you're experiencing pedal creep, don't ignore it. Prompt diagnosis and repair will ensure your safety and the longevity of your vehicle.