KJ Jones
December 19, 2013
Photos By: K.J. Jones
Quarter Master’s hydraulic clutch-release (throw-out) bearing features a racing-inspired return spring design. In addition to air gap, this helps minimize continuous bearing-to-pressure-plate-fingers contact.
Unlike popular DOT 3/brake fluid that is used in hydraulic-clutch applications, Quarter Masters’ synthetic race-clutch fluid is designed to provide a solid pedal feel and consistent pedal actuation by maintaining its viscosity in high-temperature conditions. The fluid is available in individual 12-ounce bottles (PN 30100), and one bottle is included with the throw-out bearing.
Measurement C is the final value, which represents the setup height of the clutch (distance from the tip of the clutch fingers to the flywheel) and is taken with the assembly bolted onto the engine.
Setting the proper air gap (between the face of the bearing and the pressure plate’s fingers) is critical. Calculations for determining air gap must be made, and Addiction Motorsports owner Eddie Rios stepped in to help for this segment of the installation. After measuring the amount of crankshaft flange that pokes out of the engine block and noting it as Measurement A, Eddie and Cody use a straightedge and a 12-inch vernier caliper to measure the depth from the face of the bellhousing to the face of the bearing. The bearing must be fully compressed when this measurement is taken, and the thickness of the straightedge (0.100-inch in our case) must be subtracted as well. The result of this calculation is Measurement B.
After measurements are taken, performing the calculation of: Measurement A plus Measurement C, and then subtracting its sum from Measurement B will result in giving us the amount of air gap. Quarter Master recommends air gap be set at 0.150- to 0.200-inch; an assortment of shims is included for achieving this amount.
Here is a look at how the factory hydraulic clutch-release bearing (a sprung unit) measures up against the stout Quarter Master replacement. There really is no comparison here, as the stocker’s stamped chassis and anemic plumbing is clearly inferior to that of the new bearing. Fluid flow is from bottom to top with the Quarter Master throw-out (the top fitting/line is the bleeder).
AN -3 feed and return lines are routed from the bearing through the bellhousing, which must be modified slightly to accept them both.
Lastly, the hard line for the OEM hydraulic clutch is removed, and the new bearing’s feed line is connected to the master cylinder. This union is completely plug-and-play, thanks to a fitting that mates directly into the quick-release port at the firewall.
A few pumps of the clutch pedal ready the new unit for operation. The dual-disc combination, along with Quarter Master’s hydraulic throw-out bearing, give the new clutch a clamping force that’s rated at 2,200 pounds. However, unlike other clutch systems which require the leg of Samson to operate, minimal pedal effort is needed to disengage the Quarter Master. Like most clutch replacements (single or dual-disc), it’s highly recommended that a ‘Stang be driven for 250-500 miles before romping on the gas to allow the clutch to properly seat. 5.0