RESTORING REAR BRAKE ADJUSTERS
 
The rear brake adjusters use a pair of pistons which are expanded by using a 1/4" open-end wrench to turn a special bolt with a tapered head.  These adjusters are often found inoperable because of corrosion and other contaminants between the aluminum body and the steel adjusting pistons and the adjusting bolt.  What follows is the procedure I use to restore the brake adjusters to normal operation.
 
The adjuster body is aluminum,  and the expansion pistons and bolt are steel, which can cause corrosion and render the adjuster immobile.  The following information is intended to show one way to restore the adjuster to free operation and prevent the adjuster from freezing up in the future.

After removing the brake drum and the brake shoes the adjuster is removed from the backing plate by removing two 7/16" nuts and lock washers from the back side of the backing plate.

If the adjuster is not frozen I use a 1/4" open end wrench to turn the adjusting bolt into the body of the adjuster and push the pistons out.  If the pistons or the adjusting bolt are frozen to the adjuster body you will need to persuade them a bit.
   
One method of removing the adjuster piston is to let penetrating oil soak in and rotate the piston, letting the tapered portion of the piston to push the piston out as it rotates.  The picture at the left demonstrates using a small end wrench to twist the piston.  

 
Once you have the piston rotated you can pull it out and clean it up for reassembly.  In some cases only one piston may rotate.  If one piston can be removed it may be possible to use a screwdriver or other thin tool to tap the second piston out from the access hole left by the first piston removed.

Once both pistons have been removed you should be able to screw the adjusting bolt out (assuming it is not frozen to the body).  If the bolt won't turn you may need to soak the threads with penetrating oil until the bolt is freed up from the adjuster body.  


 		 The component parts of the brake adjuster are shown in the photo to the left.  The can behind the components is anti-seize compound, which is used to coat all surfaces of the adjuster pistons and adjuster bolt to provide lubrication and prevent corrosion. 
Once the adjuster is reassembled, reattach it to the backing plate.  Lubricate the rub pads on the baking plate and install the brake shoes to complete the job.


Remember, Anti-Seize compound should be used whenever two dissimilar metals may contact each other.  This includes completely painting bolts that may pass through an aluminum body such as a timing cover or water inlet body.