My 37 Ford is a typical street/strip hot rod: A stout SBC engine, GM steering box, Muncie M-22 four-speed transmission and early Lakewood scatter-shield. I drive it on the street and race at local nostalgia drag events. When I first assembled the car, I cobbled together mechanical linkage from the 37 Ford clutch pedal to the SBC clutch fork. It worked (marginally), but was difficult to align and never operated smoothly. So I have been determined to set up a hydraulic clutch with an absolute must to retain the original Ford clutch pedal. The main challenge to using the original clutch pedal to a hydraulic master cylinder is lack of space/accessibility under the floor. And I wanted to put this together without having to blow the car apart to do it. <OMy solution was to locate the master cylinder forward near the slave cylinder, which provides room both for installation and servicing. Then connect back to the clutch pedal with an actuating rod. The addition of a bell crank provides a couple of advantages it puts this rod in tension rather than compression (much stiffer) and provides for adjusting the pedal-ratio at the bell crank. In my case, I set it up for a shorter pedal throw and live with the stiffer pedal pressure -- to accommodate quicker shifts at the drags. <OThis is back-yard engineering that may appear somewhat Rube Goldberg, but it works -- and works well. Several photos are attached. <O Other than scrap steel and rod, here are the major commercial components (CNC, Inc. is located in <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com<ST1San Diego</st1:City>): <OMaster Cylinder: CNC Series 701. I selected ¾ bore. <OSlave Cylinder: CNC Series 305 Push Style. <OSlave-Cylinder Push Rod: CNC 1312. <OBraided brake line connecting Master Cylinder to Slave Cylinder. It is six inches long. <O First step (no photo) was to rotate the arm on the stock clutch pedal 180 degrees so that it pulls rather than pushes when pedal is depressed. I drilled out the pin, rotated the arm and replaced pin with a ¼ bolt and nut. I welded an extension on to the arm with several locating holes for the to provide alternatives on ratios. <OPhotos 1 & 2: I fabricated the mounting for the master cylinder. This becomes an assembly that bolts to the bottom of the frame rail, such that the push rod from bell crank to master cylinder is actually tucked inside the frame channel. Once complete, this assembly can easily be removed and reinstalled as a module. <OPhoto 3: The frame is not parallel to the crankshaft centerline at this mounting location, so the master cylinder must be angled to establish alignment. I spent many hours of trial fitting, tweaking and tack-welding to get it to the point of final welding. <OPhoto 4: The assembly bolted into position on the bottom of the frame channel Photo 5: The rod from bell crank back to the re-positioned arm on the clutch pedal clutch pedal is in place. (Note it is essential to clock position of the bell crank to assure maximum insertion of master-cylinder push rod versus bell-crank rotation. A few degrees will make a big difference.) <OPhoto 6: This shows a mounting plate fabricated to attach the slave cylinder to the side of this Lakewood Scatter shield. A custom mounting plate could be easily fabricated to meet differing attachments of different bell housings. <OPhoto 7: Master Cylinder and Slave Cylinder in place. Yes, they are close. Lots of trial and error fitting is required to assure that they dont interfere with each other, and that the master cylinder clears the steering box. <OPhoto 8: Master Cylinder and Slave Cylinder connected. A residual valve is not required. <OServicing the master cylinder is tight; I would not try to do that around a hot exhaust. The cap of the master cylinder is easy to remove and replace from under the car. Adding brake fluid to the master cylinder is straight-forward from topside with an extended funnel. <OWhen I first serviced the master cylinder, there was air in the system that I could not remove through the bleed valve of the slave cylinder. I simply disconnected the braided line at the slave cylinder and dropped the master cylinder module from the car. On the bench, I inserted the loose end of the braided line back into the fluid in the reservoir and cycled the bell crank a few times to thoroughly bench-bleed. I reinstalled the master cylinder module and re-connected the braided line to the slave cylinder. That was two years ago, and the system has worked fine without requiring further attention.
Wow!! Exactly what I was looking for! I'm working on a 36 ford coupe, SBC and Muncie 4spd. I thank you for your post, do you have any more pics and also how smooth is the shifting,return,etc. Do you have a pic of the extension you welded to the original clutch pedal ? I'm using 39 OG pedals and was wondering if you had any issues welding to them( I'm not sure if they are cast or forged) If you don't mind me asking, which clutch fork you used? And what exhaust you are using? Again, Many thanks !
I'm glad that it may be of help. If you can look past the crappy welding, here is a photo of the extension on the clutch-pedal arm after rotating it 180 degrees on the shaft. The bolt & nut provide most of the security, welding just removes slop. Note the extra holes for more options on adjusting ratio. Clutch Fork is Lakewood #15500 HD GM. Pretty standard; nothing Special. Exhausts is Speedway Fenderwell headers for SBC in early Ford.. When finally dialed in, all works smoothly and consistently. With everyting so tight, I just had to allow a lot of time for trial fitting and tac-welding and refitting. The most difficult is the master cylinder/bellcrank inside the frame rail.
Hi Finn, Quick question,. How close is your brake pedal to the clutch arm and slave mount? Looking at the pedal on my car it swings pretty close to the trans clutch fork. Did you heat and bend the arm to clear? Thanks!
JW, I'm not certain that I completely follow your question, but I didn't have to bend any parts to clear. I only rotated the clutch arm 180 degrees on the clutch shaft that goes through the brake pedal. In my case, everything cleared no problem. I believe that the 36 Ford clutch pedal assembly is identical to my 37, so I would think that you would not have a problem. PM me with your phone # if you want to discuss. Finn
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