The braking system on a vehicle is one of its most critical systems. Brakes are especially important on an off-road vehicle. Nothing is more unnerving then being on the side of a rocky hillside and realizing your brakes are not up to the task. We will briefly cover the basic install of upgrading brake components on a 1950 CJ3A.
In the front, we will be doing a GM/CJ disc brake kit. In the rear, we will be upgrading the 9” drums to later model 11” drums. Take note that when disc brakes are installed in the front it requires you to change the master cylinder to a dual split master cylinder, which is due to the increased amount of fluid disc brakes require.The disc brake kit was sourced from The Jeep Guy. Ryan Hopkins, the owner of The Jeep Guy is a wealth of knowledge when it comes to Jeep brake upgrades. He is always willing to talk to you and go over your options for brake upgrades. To start the disc conversion, all of the original parts must be removed to get the knuckle down to the spindle. Start with removing the locking hub, next the spindle nuts, then the hub/drums, brake line to the wheel cylinder, and finally the backing plate.Once all the original parts are removed you will mount the caliper bracket in your desired location. Note that it may be necessary to use bolts that are slightly longer than the originals because the caliper brackets are thicker than the original drum backing plates. Then, mount the caliper and check the clearance between the caliper and the back of the knuckle.In this application, it was necessary to clearance the caliper and knuckle for a better fit. The calipers were marked, then removed so the knuckles and calipers could be clearanced.4Low Magazine is a print magazine about the off-road community. It features 4×4 vehicles and personalities behind the vehicles. Off-road industry news, overlanding, racing, rock crawling, adventures, tech articles and more.Wheel bearings were packed and placed in each hub then the wheel seals were installed. The hub and rotor assembly was next placed on the spindle and the nuts were installed in the reverse order from which they were removed.Brake pads were put in the calipers and then the calipers were installed on brackets. The “S” lines, that loop from the wheel cylinder to the bracket, which is bolted through the kingpin bolts, must be removed. Optionally, this bracket can be removed, as done here, but it does not have to be. The brake line is bolted to the caliper then looped around to the factory tab on the axle tube.
Locking hubs are installed and the front is done!
Next, on to the rear 11” drum upgrade. The backing plates used on this swap were sourced from AMC Salvage. These 11” backing plates are found on 72-77 CJ-5s, 72-73 Jeep Commandos, and on many Ford car and truck applications. You will need to do research on the Ford applications for a proper fit. The ones used here were from the front of a 1974 CJ-5. We were able to use the fronts of the CJ-5 because the CJ3A has a drive shaft e-brake and doesn’t need additional e-brake capabilities at the rear wheels. The rest of the parts were sourced from the local Napa Auto Parts store.
Initially, the 11” backing plates were stripped, cleaned, and painted then set aside.The rear drum was removed along with the rear axle hub. We noticed that the rear hub was cracked when it was removed, which typically happens when the key is placed in the axle upside down. In this install, the hub and key will need replaced.The backing plate can now be removed by removing the six nuts and bolts that hold it to the end of the axle housing, as well as the brake line on the wheel cylinder. The bolts also hold on the dust shield, outer axle seal, and shims. Be sure to pay attention to the order for reassembly. We cleaned and prepped the new drums and factory dust shield for assembly.The shims were cleaned and sprayed with high tack sealant and placed on new bolts. Next, the backing plate was placed on bolts and the brakes were assembled. The outer axle seal and dust shield were installed.Everything was then tightened down and the hub was reinstalled and torqued to 250 ft lbs. Rear drums were placed on and then adjusted. Brake lines were hooked back up and access holes were plugged. That finishes up the rear.The dual master cylinder kit came from ATV Manufacturing. ATV Manufacturing specializes in many upgrade kits for vintage Jeeps. First, you must remove the factory master cylinder and unhook the brake lines. The metal bracket that holds the original master cylinder must be removed to make way for new parts.Next, I prepped the new master cylinder by painting it, installing the special banjo bolts/fittings, and bench bleeding it. The bracket was held in place, located by the pedal pivot bracket, and the holes were marked. The marked holes were drilled and the bracket was bolted in place. Finally, the new master cylinder was bolted in place and the pushrod was fitted and installed.The brake lines were modified to fit the new master cylinder (note: be sure to hook the rear port, towards the back of vehicle, to the front brakes and the front port to the back brakes). Fill the fluid, bleed the brakes and enjoy being able to brake your vintage rig right.
