Parking Brake - 1954 Pontiac
I've used the original 54's pull lever parking brake handle with the 84 Toronado's rear disk parking brake mechanism. I'm hoping that there will be enough leverage to lock up the rear wheels. I won't know for sure until I get the car running. Well, I got it running and the handbrake doesn't have enough leverage. You have to pull on it with both hands to get it to lock the rear wheels. So I made a lever to double the leverage. It's documented at the bottom of this page.
Basically, I installed 84 Toronado rear brake cables and routed them to the front of the car as far as they would go. I was able to use the existing 54's rear parking brake frame brackets by cutting the bracket in two pieces - a top and a bottom. The cable is firmly clamped together in place.
1984's cable held by modified 1954's frame bracket
The right rear parking brake cable run across the top of the driveshaft tunnel.
The only way to get the right rear parking brake cable over to the left side was to run it across the top of the driveshaft tunnel. There is about a foot of clearance between the driveshaft at ride height and the cable. The driveshaft tunnel is only about 3" in depth and the picture misleads how much clearance there really is.
I terminated the cables in an angle bracket bolted to the left side of the frame. I had to space the cables out because there was an exhaust bracket trying to occupy the same space/time continuim. The exhaust bracket sits in between the two cables. You can see one of the exhaust brackets's nutserts in the frame.
Parking cable bracket
It confused me as to why the two cables were not even close to the same length. I had to make a trip to the wreckers to look at a Toronado to see how they were hooked up. Interestingly, the two cables are connected together to make a loop.
Cables are joined together to form a loop
Loop adjuster
The parking brake is adjusted by taking up the slack by tightening a threaded rod that goes through the loop adjuster. The cable loop slides "semi-tightly" through the loop adjuster.
The problem then was to determine how to connect up the existing 54's handbrake to the Toronado's cables. I ran the parking brake cable from the hand brake as far back as it would go. Surprise it was the perfect length to mate with the loop adjuster. And it had a threaded rod on the end that was the correct diameter too!
A nylon locking nut is used to lock the adjustment in place. I mounted that 54's cable clamp so that I would have maximum adjustment available on the rod when the rear caliper's parking brake lever is at the back end of travel.
The parking brake cable enters the engine compartment beneath the proportioning valve
It is quite tight fit for the parking brake cable (aluminum color) as it enters the engine compartment underneath the proportioning valve and then passes through the firewall to the passenger compartment directly behind the power booster.
I didn't want to route the parking brake cable through the existing firewall support arm cutout because the cable may interfere with the tranny linkage that passes through the cutout.
Under dash pix of hand brake mechanism.
The above picture is an under dash pix of hand brake mechanism. You can just see part of the handle in the upper left corner. The camera was on the floor next to the transmission hump to get this picture. The parking brake mechanism is painted aluminum color. The brake pedal assembly is black and is on the right side of the picture. The parking brake cable enters in from the firewall at the top right hand corner. It is hard to see how it works as the whole mechanism is oddly shaped (on 3 planes) to start with. After I had cleaned it up and painted it, it was quite difficult to figure out how to put it back together.
The cylinderical rod in the center of the picture is the handbrake which is pulled. It pulls on the flat lever which is almost vertical in the picture. The hinge is just out of the picture at the top of the lever. There is great leverage here as the parking brake cable is attached at the very top of the lever. You can just see about an inch of the cable.
Parking brake cable in silver on right
Here's the completed parking brake lever ready to be installed
This is a rear view showing the retaining washers and cotter pins
This side view shows the frame bracket and the clevis.
The extra parking brake lever was required because there wasn't enough leverage with the handbrake alone. I used a simple lever design. The handbrake cable attaches to the outside clevis and the rear disk cable attachs to the middle clevis. The lever swivels on the frame bracket which is made out of scrap angle iron. Since the handbrake clevis is twice the distance from the swivel point as the rear brake cable clevis, there is a 2x leverage action.
The only things to worry about are whether there is enough physical movement at the rear brake cable side and at the hand brake pull side. The handbrake was only being pulled about 1/4 of the travel available so there should be plenty of room with the new lever. The disk brake cable only required about an 1" of movement and there is over 2" of play available. Everything went as planned and the handbrake works well.
I used 5/16" bolts and made my own clevis pins by cutting off the threads and drilling a cotter pin hole. I was under the impression that I had purchased the clevis with 5/16" pins and went ahead with drilling the lever holes for 5/16" dia holes. Unfortunately, they were 1/4" pins, so rather than make a new piece, I drilled the clevis for 5/16" holes and made the clevis pins. It didn't take too long and looks okay. Since these pictures were taken, I've changed the frame swivel bolt to a clevis pin also.
The lever is made out of 1/4" x 3/4" stock about 3" long and the frame bracket out of 1/4" thick scrap angle iron. The clevis ends originally had 1/4" thread and I drilled and tapped them for 5/16" NF threads to match the brake cables. I had a spare brake cable with the adjustment rod attached so I cut it off and screwed it into the rear disk clevis. I used locktite on the threads and will use a jam nut to ensure that it doesn't move. It will be used for adjusting the brakes. Finally, I spray painted everything with aluminum paint cause it looked good.