Teaching Tennessee, CTE Task: Check Master Cylinder

Click here to download the teacher resource for this task. 


Maintenance and Light Repair III (MLR III)


30 Minutes


Check Master Cylinder

Task Description


Students will:

  • Read the linked materials using guided notes.
  • Watch the linked videos using guided notes.
  • Complete the worksheet.
  • Record a video of themselves describing the steps and tools involved in checking the master cylinder.


Safety Note: If possible, students should do this task with a vehicle, but ensure the students do so safely.

Check master cylinder for external leaks and proper operation. (4.4)

Overall Standard (4): Students will inspect, service, and repair vehicle brake systems.

 Content Understandings

Extending Understandings

Upon successful completion of these tasks students will demonstrate the ability to:

  • Explain why a master cylinder needs to be inspected.
  • Describe symptoms of a bad or failing master cylinder.
  • Select the tools required.
  • Locate the master cylinder.
  • Describe how to visually inspect the master cylinder and related components.
  • Explain why low brake fluid levels may indicate the master cylinder is bad.   

To move students towards deeper understanding, they should be given opportunities to:

  • Explain why the typical master cylinder has two pistons or compartments.
  • Describe how the hydraulic brake system works in a vehicle.

Support Strategies

If students are struggling to access this task, additional supports and strategies could be employed as students are engaging with the task.

Key Terms

Sentence Frames

Scaffolded Questions


The brake system is an ______________ system using the brake fluid to create pressure in the brake system to engage the brakes.

How does the hydraulic braking system engage the brakes at the wheels?



Instructional Resources


Materials to read (see guide below)


Oards Automotive Hub, Kevin (2020, June 15) 7 Symptoms of a Bad Brake Master Cylinder Click here for link


Videos to watch (see note guide below)


AutoZone (2011, April 14) How to Diagnose Problems With Your Brakes – AutoZone Car Care (Video) YouTube. Click here for link (6 minutes)

Wilwood Racing (2020, July 24) How to Check a Master Cylinder for Leaks (Video) YouTube. Click here for link (1 minute)


Additional Resources


Tech Garage (2017, April 19) Diagnosing & Replacing Master Cylinder (Video) YouTube. Click here for link (6:30 minutes)


Student Resources

Click here to download the student resource for this task. 

Student Reading Guide

How to Check the Master Cylinder

  • Test drive the vehicle, if possible, to determine how brakes are working.
  • If the vehicle pulls to one side while braking, the master cylinder may be bad.
  • Check the brake fluid level in the reservoir. Fill if needed.
  • Check the quality of the brake fluid.  If it is dirty or contaminated it could affect brake pressure and it needs to be replaced.
  • Inspect the master cylinder for signs of leaks.  Check all brake related fittings, connectors, and seals in the engine compartment.
  • Start the vehicle and apply the brakes with light pressure.  The brake should hold its position without sinking for at least a minute. If it sinks, the system may have a leak requiring further inspection.
  • Release the brake and apply it more firmly.  See if the brake pedal holds steady.  Repeat this until very firm pressure is applied.
  • If the pedal sinks or is spongy, the master cylinder may have an internal leak.



Student Video Guide

How to Check the Master Cylinder

  • How the brake pedal feels could be a warning there is a problem.  A fading, sinking or spongy pedal means the hydraulic brake fluid system is not working properly.
  • Check the brake fluid level in the reservoir. Fill if needed. Note that brake fluid is very corrosive and can easily damage vehicle paint.
  • Pump the brakes and look for a leak in the brake system.
  • Low brake fluid is a symptom of a problem in the brake system.
  • Inspect the master cylinder for signs of leaks.  Check all brake line fittings, connectors, seals and areas in the engine compartment.
  • If no other problem can be detected in the brake system and the braking problem continues, the master cylinder may need to be replaced.


Student Worksheet

Questions for after reading and watching all resources


What are possible signs the master cylinder may be bad?






What tools and parts are needed?






What needs to observed about brake fluid when working around it?






What are the tests with the brakes that can help determine if the master cylinder may be bad?






What are visual signs of problems with a master cylinder?