Never tighten the slack without first adjusting up the
brakes.
As preventative maintenance, pull the drums, check for thin pads on the
rear shoe, if they are questionable, replace the shoes.
The cables should work freely, the
self adjuster cables and the adjusters should also be bind-free and not frayed or broken.
A canted cable "splitter" indicates worn parts or mis-adjusted
brakes.
In this case, usually a cable (or even brake hardware) is stuck and has worn the
brakes down, causing the mis-alignment, but stretched e-brake cables also cause the same symptom.
If it ultimately comes down to stretched cables, replace either one, or both OR, if the stretch isn't so severe as to affect performance, use them as-is.
One of the biggest PITA and the least understood troublemaker is the AUTO BRAKE
ADJUSTER FUNCTION!
It's function it to adjust the
brakes automatically when the vehicle has rearward motion and the service (foot) brake is applied and is done with or without intentional input.
DESCRIPTION:
This is a system where a cable, one end with a moderate-tensioned spring, the other end with a loop, is routed from an anchor point, where the loop end attaches on one brake shoe.
The cable is then routed through a cable guide, then attached to an
adjuster lever, by way of a slot on the
adjuster lever catching the loop end of the cable's spring.
The
adjuster lever's other end, or "knife", aided by another spring's tension, rests on a notch on an
adjuster wheel, also called a "star" wheel, which has numerous teeth that the knife catches.
The
adjuster, or "star wheel" assembly consists of a threaded male assembly with an anchor point, which fits into the star wheel's body, which is female threaded.
At the other end of the star wheel assembly is a floating anchor point that the star wheel body rides in.
In essence the "star wheel assembly" is an axle assembly that changes length.
When backing a vehicle up and applying the brake, the brake pads apply to the drum, which rotates the brake pads ever so slightly, this motion is transferred through the cable, pulling on the
adjuster lever's "knife" into the star wheel's notches, causing it to spin and since one end is threaded, the assembly actually lengthens, causing the pad assemblies to spread.
Due to the fact the the end of the
adjuster cable is attached to the
adjuster arm via spring tension from 2 different springs, once a certain amount of tension is realized (The result of the pads contacting the drums), the springs then allows the cable to "slip" the "knife" over the teeth.
This prevents over tightening of the brake pads.
Be sure the
adjuster cable is not stretched or frayed. If it is stretched, the lever will ride too low on the star wheel and not catch the teeth, causing it to either not adjust correctly, or allow the
adjuster to back off.
The proper place for the
adjuster lever is towards the bottom of the star wheel, with the "knife" engaging one of the teeth and spring tension maintaining the knife in that position, with NO SLACK in the
adjuster cable.
A hint that the
adjuster/cable assembly has gone bad, or worked loose, is constantly having to adjust the
brakes MANUALLY to compensate for low pedal feel.
In a properly working
self-adjusting drum braking system, you should almost NEVER have to manually adjust the
brakes.
Sorry for the rambling on.
Mark.
by Ol_blue88 » Fri Nov 30, 2012 7:18 pm 
Work in progress......