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Brake caliper piston SIZE 38mm diameter x 29mm height ❭ 90135299300
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
- Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
Restore safe and reliable braking performance with this OE Match Replacement Brake Caliper Piston, measuring 38mm diameter x 29mm height, manufactured as a direct replacement. Produced to OE-style specifications, this precision-engineered caliper piston is designed to replace worn, corroded, or damaged original pistons during brake caliper overhaul and restoration.
Fits:
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
- Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
The brake caliper piston converts hydraulic brake pressure into mechanical force, pressing the brake pads evenly against the brake disc to slow and stop the vehicle. Over time, exposure to moisture, contaminated brake fluid, corrosion, or damaged piston seals can cause the piston to seize or operate unevenly, affecting braking performance and causing uneven pad wear. This OE Match replacement restores smooth caliper operation, making it ideal for professional brake rebuilds and classic Porsche restoration projects.
What This Product Does:
- Converts hydraulic pressure into braking force.
- Pushes the brake pads evenly against the brake disc.
- Restores smooth brake caliper operation.
- Helps maintain consistent braking performance.
- Reduces uneven brake pad wear.
- Provides OE-style fit and dimensional accuracy.
- Replaces worn, corroded, or seized original pistons.
Symptoms Of Wear Or Failure:
- Seized or sticking brake caliper.
- Uneven brake pad wear.
- Brake pulling to one side.
- Reduced braking performance.
- Brake drag after releasing the pedal.
- Corrosion or pitting on the piston surface.
- Fluid leaks caused by damaged piston surfaces.
- Overheating brake disc or pads.
- Difficulty retracting the piston during servicing.
- Age-related deterioration discovered during caliper overhaul.
Why Replacement Matters:
- The brake caliper piston is a critical component in the hydraulic braking system. A corroded, worn, or seized piston can reduce braking efficiency, cause uneven braking, increase brake wear, and compromise vehicle safety.
- Replacing a damaged piston restores smooth hydraulic operation, even brake pad contact, and dependable stopping performance. Manufactured to OE-style specifications, this OE Match replacement provides the correct dimensions, precise fit, and reliable durability, making it an essential component for professional brake caliper refurbishment and classic Porsche restoration.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90135299300
The product you are viewing cross references to these numbers
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
This brake caliper seal kit is designed to rebuild the front brake calipers of classic Porsche 911 models (1974-89) (non-turbo). It includes all the sealing rings, dust boots, and fasteners necessary to rebuild a single caliper, ensuring proper hydraulic sealing, piston movement, and reliability. Manufactured to original Porsche specifications.
Sold per caliper

Porsche 911 1974 - 1989
• Position on Vehicle: Front axle brake calipers, service train of the front brake system.
• Applications: Ideal when the original caliper pistons or seals have been serviced, when you observe brake lever/root pressure changes, when brake fluid contamination has occurred or during a full caliper rebuild.
The sealing components within a brake caliper are critical to safe and effective braking performance. Worn or damaged seals can lead to piston sticking, brake drag, uneven pad wear, reduced braking efficiency or fluid loss. Replacing with a correctly specified rebuild kit restores hydraulic integrity, ensures smooth piston operation and helps maintain your 911’s original braking feel.
When and why to replace:
• Caliper pistons are sticking or moving unevenly.
• Visible damage to dust boots or signs of fluid leakage around the caliper.
• Uneven pad wear or brake performance inconsistency.
• During brake pad or rotor replacement when calipers are open.
• High-mileage vehicles or cars where original seals have not been replaced.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91135194600
The product you are viewing cross references to these numbers
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
This OE Match-standard brake caliper seal repair kit is engineered as a direct-fit replacement for the rear brake caliper sealing components on classic Porsche 911 models. This kit supplies the essential gaskets, seals and dust boots needed to rebuild the brake caliper’s sealing surfaces accurately.
Sold per caliper.

Porsche 911 1984-89 (Rear)
This kit is sold on a per-caliper basis - for reconstructing or refreshing one rear brake caliper’s internal seals and dust protection.
In a brake caliper, seals and dust boots play a critical role in maintaining hydraulic integrity and protecting internal components from dirt and moisture. Over time seals can harden, crack or shrink, leading to fluid leaks, reduced braking performance, and uneven pad wear. This kit provides the correct rubber components to refresh the caliper sealing surfaces, allowing pistons to move freely while maintaining fluid pressure and protecting against contamination.
Function
• Hydraulic Seal Function: Prevents brake fluid leakage from the caliper piston bore under pressure.
• Dust Protection: Dust covers keep contaminants out of the caliper internals, reducing corrosion and wear.
• Restore Performance: Helps return caliper piston travel and braking response to as-designed levels.
• Durability: rubber materials resist heat, fluid exposure and aging typical of high-stress brake system environments.
Brake caliper seals and dust boots wear with age and use. When the seals degrade, brake fluid can leak at the caliper piston, reducing hydraulic pressure, degrading braking performance, and potentially causing uneven pad wear or pulling under braking. Dust boots that are cracked or missing allow grit and moisture into the caliper bore, accelerating corrosion and piston binding. Replacing these with an OE Match kit helps restore correct brake function, maintain consistent pedal feel, and extend the life of your brake calipers.
Replace the brake caliper seal kit if you notice:
• Brake fluid leaks around the caliper piston seal.
• Spongy or inconsistent brake pedal feel.
• Uneven pad wear or reduced braking performance.
• Cracked, hardened or missing dust covers.
• During a full brake overhaul or rebuild.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91135290500
The product you are viewing cross references to these numbers
Brake Caliper Replacement Pistons for Brembo Calipers
Sold each
Restore the performance and reliability of your Porsche Brembo braking system with these OE Match Brake Caliper Replacement Pistons. Manufactured to original equipment specifications, these precision-engineered pistons are designed for rebuilding Brembo brake calipers fitted to a wide range of Porsche models.
Available in 28mm, 30mm, 32mm, 34mm, 36mm, 38mm, 40mm and 44mm outer diameters, every piston has an overall height of 32mm and is manufactured to deliver the correct fit, smooth operation and dependable sealing performance when used with new piston seals and dust boots.
Important: Please check the piston diameter required for your specific caliper before ordering. Many Brembo calipers use two different piston diameters within the same caliper to optimise braking performance. The sizes listed refer to the outer diameter (OD) of the piston.
What Does a Brake Caliper Piston Do?
The brake caliper piston is one of the most important components inside the braking system. Hydraulic brake fluid pressure pushes the piston forward, forcing the brake pad firmly against the brake disc to generate the friction required to slow or stop the vehicle.
Its primary functions include:
- Converting hydraulic pressure into braking force.
- Applying even pressure across the brake pads.
- Ensuring smooth and consistent piston movement.
- Maintaining balanced braking performance.
- Supporting Porsche ABS and stability control systems.
- Delivering precise pedal feel and braking response.
Correctly functioning pistons are essential for maintaining the powerful, progressive braking performance expected from Porsche Brembo calipers.
Why Do Brake Caliper Pistons Fail?
Brake caliper pistons operate in harsh conditions and are continually exposed to heat, moisture and brake dust. Over time they can become damaged or worn.
Common causes include:
- Corrosion caused by moisture ingress.
- Torn or damaged dust boots.
- Contaminated brake fluid.
- Surface pitting.
- Heat generated during heavy braking.
- Seized pistons caused by corrosion.
- Damage during previous repairs.
- High mileage and normal wear.
A damaged piston can prevent the caliper from operating correctly, leading to reduced braking performance and uneven brake pad wear.
Symptoms of a Worn or Damaged Caliper Piston
Common symptoms include:
- Sticking or seized brake calipers.
- Uneven brake pad wear.
- Vehicle pulling during braking.
- Reduced braking performance.
- Overheating brakes. Brake drag.
- Fluid leaks around the piston seal.
- Difficulty retracting the piston during servicing.
Replacing damaged pistons during a caliper overhaul restores smooth operation and reliable braking performance.
When Should Brake Caliper Pistons Be Replaced?
Replacement is recommended whenever:
- Corrosion or pitting is visible.
- Pistons become seized or difficult to move.
- The caliper is being rebuilt.
- Dust boots have failed allowing contamination.
- Brake fluid leaks occur around the piston.
- Uneven pad wear is caused by sticking pistons.
- Restoring older Brembo brake calipers.
- During preventative maintenance on ageing braking systems.
For the best results, new pistons should always be installed with new piston seals and dust protection boots.
OE Match Quality You Can Trust
These OE Match Brake Caliper Replacement Pistons offer:
- Manufactured to original equipment specifications.
- Precision-machined finish.
- Excellent corrosion resistance.
- Smooth piston movement.
- Direct replacement fitment.
- Suitable for Brembo brake calipers.
- Available in 28mm, 30mm, 32mm, 34mm, 36mm, 38mm, 40mm and 44mm diameters.
- Uniform piston height of 32mm.
- Ideal for professional caliper rebuilding.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
1055955
The product you are viewing cross references to these numbers
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