Range Rover won’t start, brakes hard to push: how to fix it

If your Range Rover Sport won’t start and the brakes are hard to push, it could indicate a failing brake booster or an issue with the starting system. Check the battery, starter motor, and brake booster. Professional diagnostics may be necessary.

In this article, I’ll be discuss further of some of the signs, symptoms, causes, and possible fixes for this problem.

What models are affected?

Signs and symptoms

If your Range Rover Sport won’t start, it may indicate a problem with the starter or battery, but if this is accompanied by hard-to-push brakes, it could suggest a deeper issue.

The brake pedal may feel stiff and difficult to push down, or it may take longer to come to a halt than usual. This can be a dangerous situation, and you should avoid driving the vehicle until it’s fixed.

List of Possible OBD Codes

When encountering the Range Rover Sport won’t start, and brakes hard to push the issue, checking the On-Board Diagnostics (OBD) codes can provide valuable insight into the problem.

Some of the codes to look out for include:

  • P0504 – Brake Booster Circuit High Input
  • P0503 – Brake Switch A/B Correlation
  • P0577 – Cruise Control Brake Switch A Circuit High
  • P0578 – Cruise Control Brake Switch A Circuit Low

Common causes

Several factors can contribute to Range Rover Sport won’t start, and brakes hard to push the issue, including:

  • Brake Booster Vacuums Leaks: A vacuum leak in the brake booster can cause a decrease in vacuum pressure, causing the brakes to be hard to push.
  • Faulty Brake Booster: If the brake booster is failing or has a slight leak, it might not be able to provide the necessary boost, and the brake pedal can become stiff.
  • Bad Grommet Seals: The grommet that connects the booster to the firewall of the car can wear out and let air into the booster, affecting the vacuum pressure.
  • Brake Light Switch Malfunction: The brake light switch plays a crucial role in the functioning of the brake system. It can lead to the brake booster and other brake-related problems if it fails.

Can it be fixed without a mechanic?

If you have enough automotive experience, it’s possible to fix Range Rover Sport won’t start brakes hard to push at home with the right tools.

Join our Range Rover Facebook group

Join our new and exclusive group!
Learn, share and communicate with other Range Rover and Land Rover enthusiasts!

However, some issues are more complicated than others, and if you’re unsure of your ability to fix the issue, it’s always better to consult a mechanic.

Parts you’ll need to fix it

To fix the Range Rover Sport won’t start brakes hard to push the issue, you’ll need the following parts:

  • New brake booster and brake master cylinder
  • Grommet seal
  • New brake light switch

Tools you’ll need to fix it

To fix Range Rover Sport won’t start brakes hard to push, you’ll need these tools:

  • Socket set
  • Combination wrenches
  • Brake bleeder kit
  • Flat head screwdriver
  • Hammer

How to fix it

  1. Start by disconnecting the negative battery cable from the battery to avoid any electrical mishaps.
  2. Remove the intake manifold and the brake master cylinder.
  3. Take out the brake lines from the old master cylinder and move them to the new one.
  4. Mount the new brake master cylinder and attach the brake booster.
  5. Replace the grommet seal and attach the brake booster to the firewall.
  6. Install the new brake light switch and adjust it, ensuring it functions correctly.
  7. Reconnect the negative battery cable and test that brake pedal and start working as they should.
  8. Bleed the brake system to ensure there was no air in the lines.

Potential Alternative Causes

Other reasons for the Range Rover Sport won’t start, and brakes being hard to push issue can include defective brake lines, bad brake calipers, or a failing vacuum pump.


Why is my Range Rover Sport’s brake pedal so hard to push?

If your Range Rover Sport’s brake pedal is hard to push, it can indicate the brake booster is failing, or there’s a problem with the brake light switch.

Why won’t my Range Rover Sport start, even though the battery is good?

If your Range Rover Sport won’t start even though the battery is in good condition, it could suggest an issue with the starter, fuel pump, or ignition switch.

How can I tell if my brake booster is failing?

You can quickly tell if your brake booster is failing if the brake pedal is hard-to-push and difficult to depress.


Range Rover Sport won’t start brakes hard to push is not only frustrating but also dangerous. By understanding the symptoms, common causes, and potential fixes, you can quickly identify the issue and get your car back on the road.

Remember, if you’re unsure or uncomfortable fixing the issue yourself, it’s always wise to consult a mechanic.

Last updated and verified on 4th September 2023

Find this helpful?
Gareth Boyd
Gareth Boyd

An avid Land Rover fan, and lover of all models, specifically Range Rover Sports. Having owned over 5 Ranger Rover models, he has encountered every error code and problem you could imagine!

Leave a Reply

Your email address will not be published. Required fields are marked *