Clutch Master Cylinder Installation

Maximize hydraulic efficiency for your Bexar Pro Components clutch master cylinder. This guide outlines mandatory procedures for heavy-duty automotive and industrial systems.

CRITICAL: Verify Specifications

Physically verify your original unit’s 1-inch bore size (or equivalent) before mounting. An incorrect bore diameter will cause total system failure—either a pedal too stiff to operate or a clutch that will not release. Verify your casting number now.

Field Installation Procedures

Step 1: Bench Bleeding (Mandatory)

Before mounting to the firewall, secure the master cylinder in a vise. Fill with fresh fluid and cycle the piston manually with a smooth rod until air bubbles stop appearing. Do not skip this—trapped air in the bore is the #1 cause of soft pedals.

Step 2: Mounting & Alignment

Install the master cylinder and connect the pushrod. Ensure the rod is perfectly straight; any angle will side-load the seals, leading to premature leaks. If adjustable, verify the piston returns completely to rest to open the compensation port.

Step 3: Secure Hydraulic Fittings

Hand-thread the line into the INV (inverted flare) port to avoid cross-threading. Final-tighten only with a flare nut wrench. Standard wrenches will round the fitting and compromise the seal in high-pressure industrial applications.

Step 4: Gravity & System Bleeding

Open the slave bleeder and gravity-bleed for 10 minutes. Finish with a manual bleed, keeping the master reservoir topped off. If the reservoir runs dry, you must return to Step 1 and re-bench bleed the unit.

Expert Installation & Field Note

Since 1985, our shop has found that “ghost” clutch slipping is often caused by incorrect pushrod length. If the rod is too long, the piston cannot fully retract, trapping pressure in the line as it heats up. Always ensure a slight gap of free-play at the top of the pedal travel.