MWMNUN 12mm Rear Hydraulic Brake Master Cylinder & Caliper for 70–150cc Pit Bikes — Pre-filled, Includes Spare Pads

Compact 12mm rear hydraulic brake master cylinder and caliper assembly engineered to replace worn rear brakes on 70cc–150cc Chinese pit and dirt bikes.

This complete rear brake kit from MWMNUN arrives ready to install with brake fluid and pads already fitted, simplifying replacement or upgrade on compatible small-displacement bikes. It’s built to mount to frames with a 12mm rear wheel shaft and fits many popular models from manufacturers such as SSR, Baja, Apollo, Taotao, Coolster, Roketa, SDG, Pitster Pro, Atomik and Sikk. The package includes one assembled master cylinder/caliper and an extra set of brake pads for quick servicing.

Which motorcycles will this rear brake assembly work with?

It’s designed specifically for bikes with a 12mm rear axle; it does not fit models that use a 15mm axle. Typical applications are 70cc, 90cc, 110cc, 125cc, 140cc and 150cc pit or dirt bikes from common Chinese and entry-level brands. Always check your bike’s axle diameter and mounting points before ordering.

• Compatible with many SSR, Baja, Apollo, Taotao, Coolster, Roketa, SDG, Pitster Pro, Atomik and Sikk models
• Accepts 12mm rear wheel shaft only — not for 15mm axles
• Fits a range of 70–150cc small-displacement dirt and pit bikes
• Includes installation-ready master cylinder with fluid and pads installed

How easy is it to install the MWMNUN rear master cylinder and caliper?

Installation is straightforward for anyone familiar with basic motorcycle maintenance. The assembly comes pre-filled with brake fluid and pads installed, so you won’t need to bench-bleed the caliper in most cases. Standard tools and a torque wrench will be sufficient for mounting and hose connection.

• Pre-assembled with fluid and pads — reduces prep time
• Mounts to bikes with matching 12mm shaft and existing brake lever/hose fittings
• May require minor hose routing or banjo bolt adjustment for exact fit
• Includes an extra pair of brake pads for immediate spares

What materials and performance details should I expect?

The unit is a standard hydraulic master cylinder and caliper combination built for daily use on off-road and recreational bikes. It’s intended to restore reliable rear braking rather than improve racing performance. Construction focuses on durability and serviceability, with replaceable pads and a serviceable bleeder valve.

• Hydraulic master cylinder paired with a single rear caliper
• Replaceable brake pads included and additional spare pads in box
• Serviceable bleeder valve for routine maintenance
• Designed for everyday off-road braking loads, not high-performance racing upgrades

What after-sale support and warranty are provided?

MWMNUN backs the product with a lifetime warranty and offers customer support for fitment or quality questions. If you’re unsure about compatibility with your specific bike, contact the seller before purchase so they can confirm fit or recommend an alternative. Warranty covers manufacturing defects under normal use.

• Lifetime warranty against manufacturing defects
• Customer support available for fitment and quality inquiries
• Return or replacement processes guided by seller policy

Who is this for: This rear brake master cylinder and caliper assembly is aimed at owners of 70–150cc pit and dirt bikes who need a direct replacement for a worn or damaged rear brake on a bike with a 12mm rear axle. It’s ideal for DIY mechanics, small repair shops, and riders who want a ready-to-mount, serviceable brake unit that includes pads and fluid for a fast turnaround.