1955-57 HYDRAULIC CLUTCH INSTALLATION
1955-57 HYDRAULIC CLUTCH INSTALLATION
When automobiles were first built in the 1880's, they had mechanical clutch linkage. Your manual transmission classic '55-'57 still has clutch technology that is 125 years old! It's time to update that antiquated clutch linkage with a state-of-the-art hydraulic clutch system. Installing a hydraulic clutch system will not only remove all of that ugly, clunky clutch linkage and clean up the engine compartment and firewall, it will also give you increased clearance in the engine compartment for custom headers and exhaust. The new Hydraulic Clutch System includes a small master cylinder that mounts up under the dash out of sight. Our system uses a hydraulic release bearing so that the mechanical clutch fork in the bet/housing is also removed for an even cleaner installation. This system will work with a three finger type pressure plate or a diaphragm type pressure plate.
Image #1: The mechanical clutch linkage starts at the clutch pedal swing arm under the dash with a pushrod that routes through the firewall and connects to the cross shaft between the frame and the bellhousing bracket. A second pushrod connects the cross shaft to the clutch fork. This all works fine when everything is in good condition, but once one part starts to wear the complete system can become sloppy The clutch linkage also eats up a lot of engine compartment room which can limit your choice of headers.
Image #2: The clutch fork fits through a hole in the bell housing on the driver's side and connects to the mechanical release (throw out) bearing. The new hydraulic clutch system eliminates all of the clutch linkage, clutch fork and release bearing.
Image #3: The hydraulic clutch master cylinder mounts to the top of the brake pedal swing arm assembly under the dash. By mounting the master cylinder under the dash and not out on the firewall, the engine compartment will remain nice and clean. On 1955 and 56 cars, one hole must be drilled and on 1957 cars two holes must be drilled in the brake pedal swing arm assembly. To complete this, the assembly will need to be unbolted and removed from the car.
Image #4: The stock clutch pedal swing arm has a return spring and bracket that will need to be removed. The return spring bracket is bolted to the clutch pedal arm with two 9/16" bolts.
Image #5: The clutch pedal pushrod arm is splined to the clutch pedal shaft and secured with a 9/16" bolt, nut and lock washer. The stock arm will be replaced with a new billet arm for the hydraulic master cylinder.
Image #6: Before installing the new clutch arm, make sure the bushings on the clutch shaft are in good shape. If the shaft is wobbly, the bushings are bad. To replace the bushings, slide the pedal shaft out of the pivot sleeve and install two PIN 57-131171-1 bushings Be sure to lightly grease the bushings.
Image #7: Install the alum inum bushing in the kit onto the clutch arm shaft. Next install the billet aluminum clutch master cylinder arm. Make su re the offset of the arm is toward the left (driver side) of the pedal assembly. The arm is held to the shaft with an Allen head bolt and lock nut that will pass over the flat cut in the clutch pedal shaft just like the o riginal arm.
Image #8: The clutch master cylinder bracket bolts to the top of the pedal assembly with two 9/16" x 1" bolts, lock washers and nuts. There is an existing hole on the 1955 and 56 pedal assembly that can be used for one of the mounting holes for the clutch master cylinder bracket.
Image #9: Bolt the bracket to the top of the pedal assembly and square up the front of the bracket to the new clutch pedal arm.
Image #10: Using the bracket as a guide, drill the second 3/8" hole in the pedal assembly and bolt the bracket in place.
Image 11: On the 1957 pedal assembly both 3/8" holes must be drilled for the clutch master cylinder bracket. The rear edge of the bracket should be located 2-7/8" from the rear edge of the pedal assembly The original support rods from the pedal assembly to cowl will no longer be used.
Image #12: The clutch master cylinder bolts to the master cylinder bracket with two 5/16" X 1-1/4" bolts with lock nuts.
Image #13: The master cylinder is equipped with a threaded pushrod. The 3" long spring provided shou ld be installed onto the pushrod shaft first. Screw the coup ler onto the shaft to connect the master cylinder pushrod to the clutch pedal arm. Make sure the flat side on the coupler is facing away from the master cylinder.
Image #14: The pushrod shaft for the master cylinder can be turned so that clutch pedal height can be adjusted. This can be done on the bench.
Image #15: Once the clutch pedal height is set, lock the master cylinder pushrod to the coupler using the 5/16" fine thread nut and flat washer.
Image #16: Install the cotter pin and washer to hold the coup ler to the clutch pedal arm. The pedal assembly is ready to be installed back under the dash.
Image #17: With the pedal assembly back in the car, the clutch master cylinder will be to the right of the gauge cluster allowing clearance for the stock gauge cluster as well as any aftermarket gauge cluster. The stock wiper transmission cables and the updated Raingear system will clear as well.
Image #18: The hydraulic release bearing fits on the front bearing retainer on any three, four, five or six-speed standard transmission.
Image #19: The release bearing is adjustable in length so that it can be used with a diaphragm or three finger type pressure plate. A set collar on the release bearing may be adjusted in or out to set the proper clearance between the release bearing and pressure plate.
Image #20: The adjusting collar for the release bearing has two o-rings on the inside bore so that it will not spin. Lubricate the o-rings with a light oil and install the collar onto the front bearing retainer. The beveled side of the collar installs against the transmission face.
Image #21: Next install the release bearing onto the adjusting collar by turning the bearing clockwise until the rear face of the bearing bottoms out on the front bearing retainer bolts.
Image #22: Measure the clearance between the release bearing and the pressure plate. To make the release bearing work properly, there must be no less than .100" and no more than .300" between the bearing and pressure plate. First measure the distance from the front of the gear box to the front of the . release bearing. Our project car had a measurement of 3".
Image #23: Next measure the distance from the face of the bellhousing to the fingers on the pressure plate. Our project car had a measurement of 2- 7/8". By subtracting 2-7/8" from the 3" measurement we find that we have 1/8" (.125") clearance between the release bearing and the fingers of the pressure plate, this is within the tolerances required for the release bearing. If your measurement is not .100" to .300" turn the entire bearing assembly clockwise or counterclockwise full turns until the proper measurement is obtained.
Image #24: There are two fittings on the release bearing. The upper fitting is for bleeding the hydraulic system. A 12" long #4 steel braided hose is installed on this fitting with a bleeder fitting on the end. The lower fitting is for the supply hose from the master cylinder. The kit includes a 60" long #4 Teflon steel braided hose that connects the release bearing to the clutch master cylinder. Connect the straight end of the #4 hose to the lower fitting on the release bearing.
Image #25: With the two hoses connected to the release bearing and the bearing installed onto the front bearing retainer, the transmission may be installed. Feed the two hoses out through the hole in the side of the bellhousing where the clutch fork was installed and bolt the transmission into place.
Image #26: The supply hose can be routed through the firewall in any desired location. Make sure the hose is kept away from any moving parts or hot exhaust. The kit includes a grommet so that the hose will be protected as it passes through the firewall.
Image #27: The 90-degree end on the hose from the release bearing connects to the #4 fitting on the master cylinder.
Image #28: With everything installed it is time to put brake fluid in the clutch master cylinder. Use ONLY DOT 3 brake fluid and not silicone brake fluid. Using silicone brake fluid will damage the release bearing and void any warranty: If the gauge cluster is removed, there is room to get a container of brake fluid up to the master cylinder top to fill the master cylinder. Fill it to within 1/2" of the top. If there is not enough room to get a container of brake up to the master cylinder use the supplied squeeze ball and hose to fill the master cylinder. Spread a garbage bag out on the floor of the car to protect the carpet.
Image #29: The clutch master cylinder will bleed just like a brake master cylinder. With the master cylinder filled, pump the pedal four or five times and hold the pedal to the floor. Now open the bleeder on the #4 hose from the release bearing allowing the air to escape. Do this several times until all the air is bled from the system.
Image #30: Once all the air has been removed, the release bearing will move forward 1/2" to disengage the clutch. This amount of movement is enough to adequately disengage a three finger or diaphragm style pressure plate.
Using a couple of zip-ties, tie the two #4 steel braided hoses together so that the hoses cannot make any contact with the pressure plate when the engine is running. Enjoy your new smoothly operating clutch system using 21st century technology!