PowerStop L1378 Disc Brake Caliper - Rear Left

Rear Left OE Replacement Caliper

PowerStop L1378 is a rear left disc brake caliper built as a direct OE stock replacement for 1990-1993 Mazda Miata applications. It is remanufactured for stock-style fitment and uses a floating caliper design with a 31.67 mm steel piston for consistent rear brake operation.

PowerStop’s Autospecialty OE Replacement Brake Calipers line focuses on direct-fit hydraulic replacements for drivers restoring factory braking performance on a budget. For the Mazda Miata rear left position, this caliper is assembled with new seals, slide pins where applicable, dust boots, bleeder screws, and stainless steel brake pad abutment clips.

Key Features

• Direct replacement for the rear left brake position on 1990-1993 Mazda Miata
• Remanufactured in Chicago, IL
• Floating caliper design with one steel piston
• Cast iron caliper body with gray finish
• Includes caliper slides and mounting bracket
• Pressure tested to verify piston operation and check for leaks
• High-temperature EPDM rubber dust boots and silicone lubricant for smoother movement
• Inlet thread size: M10 x 1.0
• Bleeder screw thread size: M7 x 1.0

Detailed Description

PowerStop L1378 is engineered for drivers seeking an OE-style rear brake caliper replacement for the Mazda Miata. It bolts directly in place of the stock rear left caliper and is built with remanufactured components that are inspected and pressure tested before release. The cast iron housing, steel piston, and floating caliper layout support factory-style brake function, while the included bracket and slides help match the original mounting setup.

This part cross-references Monroe Shocks & Struts (e.g., 172286, 182286) for the same application.

What It Helps Address

• Rear brake dragging caused by worn caliper slides or piston movement issues
• Brake fluid leakage from aging seals or damaged hydraulic components
• Uneven rear braking on 1990-1993 Mazda Miata models
• Corrosion-related caliper wear on the rear left side
• Restoration of stock-style brake feel after caliper replacement

Installation Notes and Tips

Fits 1990-1993 Mazda Miata, rear left. Verify inlet thread size M10 x 1.0 and bleeder screw thread size M7 x 1.0 before installation. Transfer or replace brake pads as needed based on wear condition, and bleed the hydraulic system after installation to remove air from the brake circuit.

Quality Assurance

PowerStop remanufactures this caliper and bracket assembly in its Chicago, Illinois facility and pressure tests each unit to confirm piston operation and check for leaks. The caliper is assembled with new seals, dust boots, bleeder screws, and stainless steel brake pad abutment clips for consistent OE-style service.