LoadForce 7/8″ Hydraulic Master Cylinder for Trailer Brakes | MC78 (SKU: MC78)

The LoadForce 7/8″ Hydraulic Master Cylinder (MC78) is a heavy-duty solution for larger trailers requiring strong, responsive braking performance. With a bigger bore size than its 3/4″ sibling, this cylinder provides enhanced hydraulic force — perfect for towing setups that demand more stopping power.

Compatible with HU4 union and CW1 copper washer (not included), this unit is a direct replacement or upgrade option for trailers using 7/8″ master cylinders. Designed for use with DOT 4 brake fluid, it ensures efficient brake response when properly installed and bled.

Note: Be sure to flush out old brake fluid before installation. After connecting the lines, fill with new fluid and bleed the system thoroughly to remove trapped air. Mounting bolts and nuts are NOT included.

Frequently Asked Questions

Product Evaluation & Installation Advice

This master cylinder is best suited for:

• Trailers requiring 7/8″ hydraulic master cylinders
• Heavier loads where increased hydraulic pressure is needed
• Customers upgrading from older or underpowered braking systems

If your trailer uses a smaller size or you’re unsure of compatibility, feel free to reach out to our team for guidance.

Installation Tips:

1. Drain and flush all old brake fluid
2. Connect the HU4 union and CW1 washer (not included)
3. Secure the master cylinder using suitable bolts and nuts
4. Refill system with DOT 4 brake fluid
5. Bleed brakes thoroughly to eliminate air