REMOVAL & INSTALLATION
- Jack the car so wheels are off the ground.
- Remove the wheel or wheels where brake drums are to be removed.
- Pull the brake drum off-it may be necessary to gently tap the rear edges of the drum to start it off the studs.
- If extreme resistance to removal is encountered, it will be necessary to retract the adjusting screw. Knock out the access hole in the brake drum and turn the adjuster to retract the linings.
- Install brake drums after adjusting the linings.
- Install the drums in the same position on the hub or axle shaft as removed.
When a drum is removed, it should be inspected for cracks, scores, or other imperfections. These must be corrected before the drum is replaced.
Minor drum score marks can be removed with fine emery cloth. Heavy score marks must be removed by "turning the drum." This is removing the metal from the entire inner surface of the drum in order to level the surface. Automotive machine shops and some large parts stores are equipped to perform this operation.
If the drum is not scored, it should be polished with fine emery cloth before replacement. If the drum is resurfaced, it should not be enlarged past 0.060 in. of the original diameter.
It is advisable, while the drums are off, to check them for out-of-round. An inside micrometer is necessary for an exact measurement, therefore unless this tool is available, the drums should be taken to a machine shop to be checked. Any drum which is more than 0.006 in. out-of-round will result in an inaccurate brake adjustment and other problems, and should be refinished or replaced.
If the micrometer is available, make all measurements at right angles to each other and at the open and closed edges of the drum machined surface.
Check the drum with a micrometer in the following manner:
- Position the drum on a level surface.
- Insert the micrometer with its adapter bars if necessary.
- Obtain a reading on the micrometer at the point of maximum contact. Record this.
- Rotate the micrometer 45° and take a similar reading. The two readings must not vary more than 0.006 in.