# Clutch Master Cylinder Repair in Upland > Clutch master cylinder repair in Upland for sinking pedals and fluid under the dash. We find internal bypass and leaks, replace and bleed the system. Source: https://route66autorepairshop.com/transmission-services/clutch-master-cylinder-repair Updated: 2026-09-17 Business: Route 66 Auto Repair, 1775 W Foothill Blvd, Upland, CA 91786, (909) 608-7699 Hours: Monday to Friday 8 AM–5 PM, Saturday 8 AM–2 PM, Sunday closed **TLDR:** A worn master cylinder lets the **pedal sink** or leaks **under the dash**. We confirm it, replace it, and bleed the system. Route 66 Auto Repair in Upland replaces failing clutch master cylinders, the pedal-side pump that starts the hydraulic clutch system. When its internal seal wears, fluid slips past instead of being pushed down the line. You feel a pedal that slowly sinks at a light, or a clutch that does not release fully until you pump it. Some leak into the cabin. We confirm the master is the fault before replacing it. ## What are the signs of a bad clutch master cylinder? - The pedal slowly sinks while held at a stoplight - The clutch releases only after pumping the pedal - Fluid or dampness on the carpet or under the dash near the pedal - Fluid on the firewall behind the master cylinder - The reservoir level drops, or the fluid is dark with rubber particles ## Is it the master cylinder or the slave cylinder? Both cause a soft or sinking pedal. We look for an external leak first. A leak under the dash points to the master. A leak at the transmission points to the slave. With no visible leak, we test for internal bypass: the pedal is held with steady pressure, and if it sinks while the line and slave stay dry, the master's seal is the likely cause. On cars with a slave inside the bellhousing, we check the bellhousing drain for fluid before deciding. See [clutch slave cylinder repair](https://route66autorepairshop.com/transmission-services/clutch-slave-cylinder-repair) for that side. ## Our clutch master cylinder repair process 1. **Test the system:** Leak trace, pedal hold test and reservoir check identify the failing part. 2. **Replace the master:** The old unit is removed from the firewall and pedal, and the new unit is installed. 3. **Bleed:** The system is refilled and bled until the pedal is firm. 4. **Adjust and verify:** Pushrod and pedal settings are checked, then the car is road tested. ## What's included in master cylinder repair - Leak trace and pedal hold test - Replacement clutch master cylinder - Fluid to specification - System bleeding - Pushrod and pedal check - Road test ## Need-now or need-later? **Need now:** - A pedal that sinks to the floor - A clutch that will not release to select gears **Need later:** - A slight seep at the master with a steady fluid level ## How pricing and timing work Access varies. On some cars the master is easy to reach from the engine bay; on others, work under the dash takes longer. If the master and slave are sold as a pre-filled set, we explain the option. AAA members save 10% on parts and labor, up to $75. Our [hydraulic clutch service](https://route66autorepairshop.com/transmission-services/hydraulic-clutch-service) page explains the whole system. ## Aftercare Check the carpet and reservoir over the next few weeks. If the car shares a reservoir with the brakes, a falling level can affect both, so any drop is worth a visit. The [brake fluid condition inspection](https://route66autorepairshop.com/diagnostics-and-inspections/brake-fluid-condition-inspection) covers that side. ## Frequently asked questions ### Can I drive with a bad clutch master cylinder? If the pedal still releases the clutch, short careful drives may be possible. If it sinks to the floor or gears will not engage, have it towed. We accept tow-ins. ### Why is there fluid on my car's carpet? A leaking clutch master cylinder can drip down the pushrod into the footwell. Clutch fluid can damage paint and carpet, so it is worth fixing promptly. ### Should I replace the slave cylinder at the same time? If the slave is original and high-mileage, doing both can make sense, especially if it is easy to reach. If the slave is inside the bellhousing, we discuss timing it with a future clutch job. --- Call (909) 608-7699 or visit https://route66autorepairshop.com/contact for a written estimate.