Brake Servo
- Porsche Boxster 981 Spyder 3.8L 2016
- Porsche Boxster Spyder 718 4.0L (420 Bhp)
- Porsche Boxster 25 Years 718 4.0L Manual (400 Bhp)
- Porsche Boxster 25 Years 718 4.0L PDK (400 Bhp)
- Porsche 991.1 R 4.0L (500 Bhp) 2016
- Porsche 991.2 Turbo Coupe 3.8L (540 Bhp) 2016-19
- Porsche 991.2 Turbo S Coupe 3.8L (580 Bhp) 2016-19
- Porsche 991.2 Turbo Cabriolet 3.8L (540 Bhp) 2016-19
- Porsche 991.2 Turbo S Cabriolet 3.8L (580 Bhp) 2016-19
- Porsche 991.2 Speedster 4.0L (510Bhp) 2019
- Porsche 991.2 GT3 4.0L (500 Bhp) / GT3 RS 4.0L (520 Bhp) 2017-19
- Porsche 991.2 GT2 RS 3.8L PDK (700 bhp) 2018-19
- Porsche Cayman GT4 3.8L 2015-16
- Porsche Cayman GT4 718 4.0L / GT4 RS 718 4.0L

Fits:
- Porsche Boxster Spyder 3.8L 2016
- Porsche Boxster Spyder 718 4.0L (420 Bhp)
- Porsche Boxster 25 Years 718 4.0L Manual (400 Bhp)
- Porsche Boxster 25 Years 718 4.0L PDK (400 Bhp)
- Porsche 991 Turbo Coupe 3.8L (540 Bhp)
- Porsche 991 Turbo S Coupe 3.8L (580 Bhp)
- Porsche 991 Turbo Cabriolet 3.8L (540 Bhp)
- Porsche 991 Turbo S Cabriolet 3.8L (580 Bhp)
- Porsche 991 R 4.0L (500 Bhp)
- Porsche 991 GT3 4.0L (500 Bhp) / GT3 RS 4.0L (520 Bhp)
- Porsche 991 GT2 RS 3.8L PDK (700 bhp)
- Porsche 991 Speedster
- Porsche Cayman GT4 3.8L 2015-16
- Porsche Cayman GT4 718 4.0L / GT4 RS 718 4.0L
Click 'Zoom in' for large parts diagram.
Diagram ref no 4
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99135512584
The product you are viewing cross references to these numbers
High-Quality Brake Servo Units for Strong, Consistent and Safe Braking Performance
A brake servo—also known as a brake booster—is an essential part of the vehicle’s hydraulic braking system. It uses vacuum or pressure assistance to reduce the amount of force required on the brake pedal, allowing the driver to achieve strong, controlled braking with minimal effort. Whether used in classic models or modern braking systems, a healthy servo is critical for maintaining safe braking performance, predictable stopping distances and a comfortable pedal feel.
Brake servos are vital for both everyday driving confidence and high-demand situations where maximum braking efficiency is essential.
What a Brake Servo Does
Brake servos perform several key functions:
- Amplify
braking force using vacuum or hydraulic assistance
- Reduce
pedal effort, improving comfort and responsiveness
- Ensure
consistent braking pressure across varying driving conditions
- Improve
brake modulation, allowing smoother, safer braking
- Support
ABS and advanced braking systems by stabilising hydraulic pressure
- Enhance emergency braking performance when rapid deceleration is required
Without a properly functioning brake servo, braking becomes harder, less predictable and potentially unsafe.
Why Brake Servos Commonly Fail
Brake servos can wear out or malfunction due to age, usage
conditions and environmental factors. Typical causes of failure include:
- Vacuum
leaks in seals, diaphragms or hoses
- Internal
diaphragm rupture affecting assistance levels
- Corrosion
inside the servo housing from moisture intrusion
- Check
valve failure, causing loss of vacuum retention
- Brake
fluid contamination damaging internal components
- Wear
from sustained heavy braking in performance or towing environments
- Heat and age-related degradation of rubber components
Failure symptoms often include a hard brake pedal, poor braking efficiency, hissing noises, long stopping distances or inconsistent pedal feel.
Why You Should Replace a Faulty Brake Servo
Replacing a worn or failing servo with a high-quality,
precision-built alternative engineered to match original braking performance
specifications is essential for driver safety and system integrity.
Advantages include:
- Restored braking assistance and smoother pedal operation
- Reduced stopping distances and improved safety
- Reliable vacuum or hydraulic support under all driving conditions
- Correct functioning of ABS and other brake control systems
- Prevention of brake fade caused by excessive pedal effort
- Enhanced driving comfort, especially in urban and stop-start conditions
A new servo unit dramatically improves braking consistency and ensures your vehicle remains safe and responsive