Brake Caliper Piston SIZE 48mm diameter x 34mm height  ❭  91135191800

Brake caliper seal repair kit. REAR
Repair kit designed to rebuild the rear brake calipers of classic Porsche 911 models from the 1969–77. This kit includes all necessary sealing rings, dust boots and associated hardware required to restore proper hydraulic operation and sealing integrity of the “M-type” steel calipers.
Sold per caliper.


Porsche 911 1969-77 REAR.
"M" type The S calipers are aluminium and the M calipers are steel

• Position: Rear axle brake caliper assembly—used to rebuild one caliper (sold each).

•  Applications: Ideal for use when calipers show signs of leakage, piston sticking, seal degradation or during full brake system overhaul/restoration.

Brake caliper seals and boots are crucial for maintaining hydraulic function, preventing fluid leaks and ensuring piston mobility. When seals wear out, you may experience brake drag, uneven pad wear, reduced stopping performance or fluid leakage. Replacing with a correctly specified kit ensures safe, consistent braking under all conditions.

When and why to replace:
• Visible brake fluid leakage around the caliper body or piston boot.
• Caliper pistons sticking or uneven pad wear.
• Brake overhaul where pistons are removed and seals are exposed.
• Restoration of vehicles where the original seal kit has not been replaced in decades.

Related reference numbers
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91135299800

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Brake caliper seal repair kit, REAR.
OE Match rear brake caliper seal repair kit designed to service the rear brake calipers on classic Porsche 911 (1974–1983) models. Now you can restore your brake calipers performance with our Rebuild Kits. Each kits includes the necessary seals and dust covers that you will need for the rebuild process.
Sold per caliper.


Porsche 911 1974 - 1983

The brake caliper seal kit replaces the internal piston seals, dust boots, and associated rubber components within the rear brake caliper. These seals perform essential functions:
•  Maintain brake fluid integrity inside the caliper piston bore
•  Prevent fluid leakage under hydraulic pressure
•  Protect internal components from dirt, moisture, and debris
•  Enable smooth piston movement for consistent brake pad engagement
•  Help ensure even pad wear and reliable stopping performance.

Over time, original caliper seals harden, crack, or lose elasticity, which can lead to leaking, sticking pistons, uneven braking, and reduced safety.

Function
•  Hydraulic sealing: Ensures brake fluid stays within the caliper bore
•  Piston movement control: Allows smooth, controlled piston travel
•  Dust and dirt exclusion: Prevents contaminants from entering the caliper bore
•  Brake performance preservation: Helps maintain even pad engagement and return.

A properly rebuilt caliper with new seals helps restore brake responsiveness and reduces the risk of brake drag or uneven braking at the rear wheels.

Brake caliper seals are critical for hydraulic braking performance and safety. Old seals often suffer from: • Hardening and cracking due to heat and age • Swelling or deformation from fluid contamination • Loss of elasticity, causing piston bind or leak paths • Corrosion of caliper bores when moisture enters through failed dust boots Worn or leaking seals result in reduced brake performance, fluid leakage, uneven pad wear, brake drag, and compromised stopping power. Replacing them with an OE Match seal kit restores proper fluid retention and piston mobility - increasing safety, consistency, and brake system longevity. When to replace. Install this rear brake caliper seal kit when: • Calipers are leaking fluid around the piston area • Brake pistons stick or bind, causing brake drag • You are performing a full caliper overhaul • Pads and rotors are replaced and calipers are difficult to service • Dust boots are torn, brittle, or missing. A seal kit is a core part of brake caliper rebuilds and should be considered whenever the caliper is disassembled.

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

91135299800

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Brake Caliper seal repair kit, FRONT.
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