HOW TO: Install an MDL LF Series Hydraulic Clutch System

Why settle for a heavy pedal when you can install Modern Driveline’s LF Series in a weekend?

Text & photography by Jim Smart

LF Series External Slave

If you like driving your classic Mustang for those great feelings of nostalgia but dread the energy it takes to shift gears, you’re going to want to hear about the new LF Series Hydraulic Clutch Kit from Modern Driveline. Available for ’65-’78 and ’79-’04 Foxbody Mustangs, the LF Series is the latest innovation from Modern Driveline, which has long been known for easy-to-install and adjusts cable clutch release systems and complete five-speed conversion kits for classic Mustangs. Once you switch to a hydraulic clutch, you will wonder how you ever got along without it because the pedal effort is more effortless with smooth operation. Marlon Mitchell of Marlo’s Frame & Alignment in Chatsworth, California, helped us with the installation of the LF Series system on his first-generation Mustang, which took a day to perform, even with transmission and bellhousing removal for clutch and flywheel replacement. Modern Driveline offers a bracket that enables slave cylinder installation without removing a five-speed. For other transmissions, such as a Toploader, call Modern Driveline for details.

	The LF Series hydraulic clutch system from Modern Driveline includes everything you’ll need for installation over a weekend. With Wilwood hydraulics, the LF system offers durability and smooth function. Price is $235 for the master cylinder and underdash linkage. The external slave is another $225 or $245 depending upon application.
	While we’re at it, we’re going to install a Superior diaphragm clutch and 28-ounce offset balance flywheel from Modern Driveline. This is an outstanding clutch package for the money, offering a clutch alignment tool, needle pilot bearing, release bearing, and a bi-friction disc. Price is approximately $178 for a basic stock clutch. High-performance clutch packages will cost more.
	Our first order of business is removing the transmission and bellhousing. We started by draining the Tremec T-5 transmission in order to keep the job neat. Your Mustang may have a 3.03 three-speed or Top Loader four-speed, which do not use automatic transmission fluid.
	Driveshaft removal is next, taking note of indexing by marking the shaft and yoke. Also, remove the starter and disconnect the negative battery cable. Disconnecting the parking brake cable will also make way for transmission removal.
The old Z-bar clutch linkage is removed next. Because these antiquated bell crank linkages are susceptible to failure, it is not uncommon to find them cobbled up with welded reinforcements.
	Bellhousing bolts are removed next with a 5⁄8-inch socket. Make sure the transmission is properly supported.
Remove the transmission crossmember, then use a transmission jack to lower the transmission out of the car.
	How you install the LF Series hydraulic clutch kit depends on your bellhousing and transmission. When you order this system, be very specific about what you have, right down to the bellhousing and transmission type. The slave cylinder bracket is positioned for marking and drilling on this T-5 bell.
	The bellhousing is drilled as marked with a 3⁄8-inch bit at low speed for a smooth cut.
	This is a Ford E6ZA-AA bellhousing for a 5.0L engine with the slave cylinder bracket installed. You can also use an internal slave/release bearing for a cleaner installation. The only negative to that is transmission removal should it require service.
	The slave cylinder is mounted on the bell like this. Bolt hole selection depends on required pedal travel and height.
The slave cylinder connects to the clutch fork as shown and is easy to adjust.
	Reinstall the bellhousing assembly with the Modern Driveline slave cylinder installed.
	The Wilwood master cylinder attaches to the firewall like this. Use the mount as a template and follow instructions to the letter. The master cylinder is positioned at an angle relative to the firewall plug (’65-’66 shown). Mark the firewall and ascertain position before cutting with a 1-inch hole saw.
This is the underdash clutch master cylinder linkage on a display model for ease of understanding. If your clutch pedal is distorted and worn out, Modern Driveline has new clutch and brake pedals for perfect fit and function.
	The installed and adjusted Wilwood slave cylinder is easy to access and adjust. You can use a modified Ford clutch fork dust cover to house this installation.
	The Modern Driveline hydraulic clutch system takes time to bleed so be patient until all air is removed. Use DOT 3 brake fluid and take extra care never to get it on paint.