Jeep CJ 1945-1970 Repair Information

Brake Drum



Brake linings may contain asbestos. Asbestos is a known cancer-causing agent. When working on brakes, remember that the dust which accumulates on the brake parts and/or in the drum contains asbestos. Always wear a protective face covering, such as a painter's mask, when working on the brakes. NEVER blow the dust from the brakes or drum! There are solvents made for the purpose of cleaning brake parts. Use them!

Clean, high quality brake fluid is essential to the safe and proper operation of the brake system. You should always buy the highest quality brake fluid that is available. If the brake fluid becomes contaminated, drain and flush the system, then refill the master cylinder with new fluid. Never reuse any brake fluid. Any brake fluid that is removed from the system should be discarded.


The front brake drums are attached to the wheel hubs by five bolts. These bolts are also used for mounting the wheels on the hub. Press or drive out the bolts to remove the drum from the hub.

When placing the drum on the hub, make sure that the contacting surfaces are clean and flat. Line up the holes in the drum with those in the hub and put the drum over the shoulder on the hub. Insert five new bolts through the drum and hub and drive the bolts into place solidly. Place a round piece of stock approximately the diameter of the head of the bolt, in a vise. Next place the hub and drum assembly over it so that the bolt head rests on it. Then flatten the bolt head into the countersunk section of the hub with a punch.

The run-out of the drum face should be within 0.030 in. (0.762mm). If the run-out is found to be greater than 0.030 in. (0.762mm), it will be necessary to reset the bolts to correct the condition.

The left-hand hub bolts have an L stamped on the head of the bolt. The left-hand threaded nuts may have a groove cut around the hexagon faces, or the word LEFT stamped on the face.

Hubs with left-hand threaded hub bolts are installed on the left-hand side of the vehicle. Late production vehicles are equipped with right-hand bolts and nuts on all four bolts.


See Figures 1 through 6

Click image to see an enlarged view

Fig. Fig. 1: After removing the rear wheel, access can be gained to the rear brake drum

Click image to see an enlarged view

Fig. Fig. 2: Remove the cotter pin from the castellated axle nut ...

Click image to see an enlarged view

Fig. Fig. 3: ... then remove the axle nut itself

Click image to see an enlarged view

Fig. Fig. 4: Remove the flat washer from the end of the axle shaft

Click image to see an enlarged view

Fig. Fig. 5: It may be necessary to use a drum puller to remove the drum

Click image to see an enlarged view

Fig. Fig. 6: While removing the drum, make sure to keep track of the axle shaft key

The rear brake drums are held in position by spring clip type locknuts, a central axle nut and cotter pin or by three drum-to-hub retaining screws, depending on the model and year. After the spring-type locknuts or retaining screws are removed, the drum can be slid off the axle shaft or hub and brake shoes. It may be necessary to back off the brake shoe adjustment so that any lip on the inside of the brake drum clears the brake shoes.

For models equipped with central axle nuts and cotter pins:

  1. Position wheel blocks around the wheels which will stay on the ground to keep the vehicle from rolling. Raise and safely support the vehicle on jackstands.
  3. Remove the wheels.
  5. Straighten the cotter pin ends and pull it out of the castellated axle nut. Discard the old cotter pin and make certain to get new cotter pins for reassembly.
  7. Remove the castellated axle nut and flat washer from the axle shaft.
  9. Pull the brake drum off of the axle shaft. It may be necessary to use a hub puller to loosen the drum from the axle shaft.

While removing the brake drum, make certain to keep track of the axle shaft key.

To install:
  1. Make sure that the key is installed in the key groove in the axle shaft, then slide the brake drum onto the axle shaft so that the key groove in the drum is aligned with the key in the axle shaft.
  3. Tap the drum onto the axle shaft with a soft-faced hammer until the castellated axle nut can be threaded onto the axle shaft.
  5. Slowly tighten the axle nut to draw the drum completely onto the axle shaft.
  7. Once the drum is completely drawn onto the axle shaft tighten the axle nut to 150 ft. lbs. (204 Nm).
  9. After tightening the axle nut to 150 ft. lbs. (204 Nm), continue to tighten it until one of the castellated grooves is aligned with the cotter pin hole in the axle.
  11. Install a new cotter pin through the axle nut and the hole in the axle shaft, then bend the ends of the cotter pin so that it cannot work its way out during use.
  13. Adjust the brake shoes, if necessary.
  15. Install the wheels and tighten the lug nuts until snug.
  17. Lower the vehicle and finish tightening the lug nuts.


Using a brake drum micrometer, check all drums. Should a brake drum be scored or rough, it may be reconditioned by grinding or turning on a lathe. Do not remove more than 0.030 in. (0.762mm) thickness of metal.

Use a clean cloth to clean dirt from the brake drums. If further cleaning is required, use soap and water. Do not use brake fluid, gasoline, kerosene or any other similar solvents.