Introduction

If your Volvo 240's brake pedal is especially soft or loses pressure while you're holding the brakes, it could be a bad seal in the master cylinder.

Parts

Image 1/1:
  • The brake master cylinder is located directly underneath the brake fluid reservoir near the driver side of the engine bay.

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Image 1/3: Remove as much brake fluid from the reservoir as possible by sticking a clean rag inside the reservoir. Image 2/3: When you remove the rag, be sure not to place it on any painted or plastic surfaces. Brake fluid will strip paint and deteriorate plastic. Image 3/3: When you remove the rag, be sure not to place it on any painted or plastic surfaces. Brake fluid will strip paint and deteriorate plastic.
  • Twist the brake fluid reservoir cap counterclockwise and remove it.

  • Remove as much brake fluid from the reservoir as possible by sticking a clean rag inside the reservoir.

  • When you remove the rag, be sure not to place it on any painted or plastic surfaces. Brake fluid will strip paint and deteriorate plastic.

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Image 1/2: Image 2/2:
  • If your brake fluid reservoir has a fluid level sensor, disconnect it by pressing down on the plastic tab and pulling the connector straight out of its socket.

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Image 1/1: There were still be fluid in the master cylinder that will drip out of the connections; this is normal. Use a clean rag to clean up any dripping fluid.
  • Use a 10 mm open end wrench to disconnect the two brake lines from the master cylinder.

  • There were still be fluid in the master cylinder that will drip out of the connections; this is normal. Use a clean rag to clean up any dripping fluid.

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Image 1/2: Remove the brake master cylinder, taking care not to damage or bend the brake lines. Image 2/2: Remove the brake master cylinder, taking care not to damage or bend the brake lines.
  • Use an open end or socket wrench to remove the 17 mm nuts on either side of the master cylinder that attach it to the brake booster.

  • Remove the brake master cylinder, taking care not to damage or bend the brake lines.

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Conclusion

To reassemble your device, follow these instructions in reverse order.

Don't forget to flush & bleed with new brake fluid! (separate how-to required)

One other person completed this guide.

David Hodson

Member since: 04/13/2010

122,199 Reputation

136 Guides authored

One Comment

Thanks this was great. Additional instructions are required about how to disconnect the reservoir from the master cylinder. I've broken so many plastic bits on my Volvo that I was scared to really put much force into getting the reservoir off. I kept thinking "There must be a trick..." but no there's no trick you just have to pull really hard while doing your best to not damage the reservoir. Could have saved me some time as I stared at it wondering what the "trick" could be.

There's also a plug on one side of the old master cylinder that you will need to take out and put on your new one.

Thanks again for posting these instrux.

Brant Louck - Reply

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