I recently converted my 32 pedal ***embly to hydraulic. I cut and rewelded the brake arm to the bottom of the brake pedal to line up with the 40 master cylinder that is mounted behind the k member. My question is where should I put the return spring. I bought both the regular stock style and a cross shaft brake return spring from Macs. I cant figure out how the cross shaft return spring fits into the ***embly. Has anyone used this application or a picture would be very helpful. Thanks.
after modifying your pedal ***embly you must recheck the pedal ratio for the mechanical advantage. Do so by measuring the height of the pedal from the pivot center to the top of the pedal arm, record the distance. Now remeasure the distance from the pedal pivot centerline to the center line of the master cylinder push rod. Now divide the distance measurement of the master cylinder arm into the distance of the brake pedal arm. ex 9"(pedal) divided by 2" (mastercyl) equals your pedal ratio (4.5). You should have a pedal ration from 6-1 to 7 to1 for adequate brake leverage. To fasten the pedal return spring just hook a spring to the pedal arm so it pulls the arm back to bump on the floor board. You also can get a 1" diameter spring and place it over the master cylinder push rod so it compresses between the master cylinder body and the lower pedal arm, when you compress the master cylinder to brake it will compress the spring, when you let up on the pedal the spring expands and returns the pedal to position.
On my similar conversion, I used one of those pins in the brake pedal arm that has the head to hook a spring on. I think it's used on the clutch pedal originally. Then made a small 3" tab that hangs down from the front of the chatter rod, held on by the nut on the front of the chatter. Ran a spring from the pin to the tab.
I use a stop collar (ace hardware or local farm store) and spring that is big enough to sit on the snap ring that holds the mc plunger. If your using the rubber boot get a spring big enough to go over teh boot. (yes I know, the pushrod is facing the wrong way.)
I am using a similar compression spring setup as da tinman, but found I had to add another return spring from the pedal itself to allow fast and positive releases. Check to make sure the spring does not bind before a full master cylinder stroke can be made-very important!
I did mine using old Ford parts. Pivot pin with shoulder for spring. The loop I think is from Model A brake rods.. Picture worth 900 words?? 1800 worth,click to enlarge.
Attn: Reefer, To answer your question you are not changing the height of the pedal from the central pivot. The stock 32 pedal has an actuator point on the upper portion of the pedal arm that moves forward to actuate the mechanical brakes. To convert to hydraulic brake you must reverse the direction of motion to push rearward and this requires you to fabricate a new throw arm on the lower portion of the pedal ***embly. It is at this point the the mechanical advantage is determined. Vaphead has an excellent picture of this setup giving you a good example and a neat little return spring holder.
Also Richard at Earl V8 garage has a hydraulic brake conversion kit that lets you use the original petals without modification. link: http://www.earlyv8garage.qpg.com/ If I ever get my new Lincoln brake backing plates I will let everyone know how it works. Rich
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