Brake master cylinders

The brake master cylinder is the part that transforms your finger pressure on the lever into hydraulic pressure to clamp your brake pads onto the disc. It's safe to say it's a critical component of your motorcycle. At Holdfast, we distribute the KustomTech range —an Italian brand specializing in custom parts machined from solid blocks of aluminum, renowned for the precision of its machining and the durability of its components. The defining characteristic of most KustomTech master cylinders is that they are cable-operated , not directly by the handlebar lever. This allows for a minimalist design on the handlebars: no more large black plastic housing, just the lever and the cable that activates the pump hidden under the seat or behind the tank. This is what creates the clean aesthetic sought after by builders of choppers, bobbers, and heritage café racers . The Deluxe versions add value with hand-finished details (polished aluminum, anodized black, brass inserts) that match the rest of the Deluxe line. Here you'll find four product families:

Repair kits — to refurbish an existing master cylinder (seals, pistons, original springs)
Basic cable-operated master cylinders — 14 mm bore, to free the handlebars when mounting the hidden pump
Master cylinders with integrated oil reservoir — compact version that avoids the ugly external jar
Deluxe Master Cylinders — Premium line with polished aluminum and black anodized finishes, brass inserts
Custom rear brake master cylinder — Ultra-compact design for streamlined projects
All models are in 14 mm (9/16″) bore — The universal size for most brake or clutch applications on custom Harley and American custom projects. The 33 to 38 mm mounting hole spacing allows it to fit standard custom plates. Caution: these cable-operated master cylinders require cable handlebar controls (wire handlebar controls) compatible to function. If you are still using stock hydraulic controls, this part will also need to be changed.To create a cohesive cockpit from A to Z, match your master cylinder with the rest of the Deluxe KustomTech line: risers, handles, levers, handle rings, dressersHoldfast distributes the complete range from Marseille: 48-hour shipping, secure payment, free delivery on orders over €150 in mainland France, and free 14-day returns. If you have any doubts about compatibility with your motorcycle, contact us—we know the KustomTech range inside and out.

Custom Motorcycle Brake Master Cylinder FAQs
Which brake master cylinder should I choose for my Harley?
It depends on your caliper: for a Harley single-disc front brake, a 12mm bore is sufficient. For dual-disc or 4-piston calipers, aim for 14mm. KustomTech offers both bore sizes in its Classic and Deluxe lines.
What is the difference between a cable-operated and a hydraulic master cylinder?
Hydraulics (the modern standard) offers progressive braking with precise modulation. cable (Mechanical) requires more effort but gives a pure vintage look — often preferred on old-school choppers. Choose according to your style and riding habits.
Is the KustomTech master cylinder road legal?
Yes, all KustomTech master cylinder parts are approved for European road use (ECE standard) and are compatible with motorcycle insurance. You can install them legally.