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CHOPPED 1972 CHEVELLE ! 4 INCH VERTICAL DROPPED TOP!
|Pinion Mounted Parking Brake:
This pinion mounted parking brake is something I concocted out of necessity on another project. It was a tubbed wagon and that particular set I did had very offset wheels that came inward so far that it didn’t leave room for conventional parking brake cables. So I built this pinion mounted brake system to relocate the parking brake away from the regular brake rotors. Now, I like this set up a lot because it allows me to use (as described in the rear brake build section above) the same rear rotors and calipers that I use in the front from a 2002 Camaro. So the following is what and how I built this alternative parking brake system.
Build Instructions for Parking Brake Kit for Chevy car 12 bolt (68-72)
First I made a template of what I wanted then I plasma cut it out of 3/8” thick steel.
Then I cut out a template to cut holes where the caliper posts get mounted.
To the right is the fixture that I use to position the caliper tubes onto the bracket to be welded.
Then I built a fixture to position the bracket in so that I could weld the 1” x ¼”thk mounting tabs where they needed to go as well as the tab to mount the brake cable.
Weld 1/8” gusset in and drill and install grease fittings in tube, check fit everything.
Installation Instructions for Parking Brake Kit for Chevy car 12 bolt (68-72)
The rotor I purchased from Streetrod MFG. CO.,INC (TSM). Part number #0640 8” dia., with 2-31/32 x 1-9/16 yoke hole-pattern.
I still had to drill out the holes to 3/8” to fit.
I had to grind yoke “ears” to fit rotor over yoke to back side.
If pinion seal shield does not leave clearance for thru bolts and nuts, remove yoke and machine mounting face for rotor to mount. May need to remove shield.
I did on this yoke but in the past I did not.
I unfortunately, had the yoke installed before I knew that the rotor would not fit without this mod. In the past, the yoke that was on the rear did not need the face machined.
So I had no choice but to remove the yoke to do this. After the yoke was modified I bought an “inch; torque wrench.
I reinstalled the yoke, removed the calipers and rotors so they did not cause drag on the yoke, reinstalled the lock washer and nut torqued it down to 200 lb-ft.
Then check it with the inch pound wrench. The rear pinion rotational resistance should be 9 to 10 inch pounds. I ended up with a final torque on the big yoke/pinion nut of 250 lb-ft.
If you torque it too much you will crush the “crush sleeve” inside and it will need to be taken apart and replaced. You will get too much play in the gears.
Most people say if you remove the yoke, you need to replace the crush sleeve. We’ll see.
Run the bolts from the front side through the u-joint straps (Girdle Kit- Moroso #85810) to mount the rotor to the yoke with nuts.
Assemble caliper with tubes, bolts and lock nuts, and place loosely assembled tubes and bolts into main bracket tubes, then tighten caliper bolts.
Ensuring that tubes and bolt heads are allowed to slide freely in and out of the main bracket tubes.
-Put caliper on main bracket and over rotor. Tighten caliper to position main bracket ears with differential housing webs. Locate brake pad to edge of rotor.
Tighten caliper pads with caliper lever so that the caliper holds in true position with respect to rotor and forces main bracket in correct position.
Slide main bracket from front to back using the secured caliper and its tubes as the guide to find the best location (front to back) for the bracket relationship to the rear diff. webs.
Drill 5/16” holes through ears and diff. webs keeping holes as far as possible from the edges of the diff. webs.
* Be sure to leave clearance for nuts on underside of webs without hitting.
One suggestion is to mark hole locations on bracket ears, remove everything and drill, then replace and match drill webs. Do one at a time.
Drill one hole, put 5/16-24 x 1”L grade 8 hex bolt in, do second and so on to maintain proper positioning. That’s it.
Now, to ensure that the parking brake system does not bottom out on the frame it is necessary to raise the 3 bumpers.
The 2 on the rear housing out by the spring perches and the one in the middle between the rear pumpkin and the frame cross member.
I built this aluminum bumper extension to insure that the rotor did not bottom out on the frame cross member.
Also I ground the caliper a bit and bent back the frame lip shown in the above picture.
This is with the suspension bottomed out. There was 3.25” between the frame and the top of the bumper when the shocks were fully extended and with no body weight on the chassis.
I melted down “soda” cans and poured them into a steel tube. You could just buy a bar of aluminum but I didn’t want to wait. Then,
I took them out and machined them to 2” diameter x 3” long with 3/8-16 threads 1” deep on top, ½-13 x 1” deep on bottom.
Used a big washer and bolt through the old bumper mount slot to match it up directly under the frame.
Then the Energy Suspension bump stop 9.9101G from AutoZone screwed right in the top side.
Now the suspension cant bottom out on the pinion mounted parking brake. I am running a 2000 Neon center console with the hand brake assembly in it.
This will match up nicely with this parking brake.