Guys,
Shane is spot on, the handbrake mechanism really is a strange arrangement. I have found this step by step procedure which mirrors Shane's explanation. It worked for me. Hope that this helps.
These pads require adjustment at 6,000 mile intervals.
1. Put front of car on stands
2. Remove front road wheels, ensure that the disc rotor is firm. Bolt if necessary.
3. Release the handbrake lever inside the car
4. Clean the cable passages and spring mechanism. Spray the cable assembly
with WD-40. Make things move freely.
5. Remove the nuts on each cable end using a 11mm spanner. Don't twist the cable too much, use locking pliers if necessary. These cables tend to need cleaning to allow the nuts to go on and off easily, this is important so do that once the nuts are off.
6. Pull each cable, one at a time, as far down through the assembly as possible and measure the length of cable sticking out from the bottom of the assembly on each side. Record the measurement.
7. Note the length for each side and calculate the difference between the two. This difference must be maintained when the cables are reassembled.
8. Remove the cable and cable return springs
9. Slacken the lock-nut (8mm??) on the top stop bolt of the inner arm, and
screw the bolt inwards several turns.
10. Using a 17mm socket wrench, loosen (don't remove) the bolts holding the brake pad lever/eccentrics in place. (See note at bottom.)
11. Using a common screw driver inserted in eccentric adjust the OUTER eccentric so that there is 0.5mm gap between the arm and the pad (turn the eccentric so that it turns up to tighten against the pad). If the disks are in good condition or the pads are new this may be reduced to 0.3mm??? It soon opens out to its natural value.)
Be sure to use a clockwise rotation on the left side cam and anti-clockwise on the right side cam (each calliper has a right side and left side cam. Right and left are determined as if sitting in the car). The aim here is to have the tab on the cammed device be centred on the brake pad so the pad wears evenly.
Next, adjust the INNER eccentric so that there is 0.5mm gap between arm and
pad when the OUTER arm is held against the stop - use a rubber band to hold it out.
12. Adjust the eccentrics until the pad is touching the rotor but you can still move the rotor using only moderate force.
13. Holding the eccentrics in place, tighten each bolt.
14. Test the freedom of movement of the rotor again, repeat steps 10
- 13 if necessary until the gap is correct. Each side of the calliper
(each pad) is adjusted independently. Some drag is expected.
15. Next add the return coil springs (not the cables) and adjust the nut-and-bolt on the inner arm so that it just contacts. The absolute key is to ensure those backstops are touching or within 10 thou of an inch of touching. This stops the mechanism rattling and moving and thus wearing the pads with the hand-brake off.
16. When both sides are adjusted reassemble the cables. Tighten the first nut until it just bottoms out on the brake assembly. Do not lock the nuts yet, you must pull the cable through on each side to ensure the difference between sides is the same as when you started.
Note also that the handbrakes are NOT adjusted by screwing the cable nuts further up on the cable. This is important. The cable ends can become so long that they scrap the inside of the wheel.
Now pull the hand-brake lever on and off several times and adjust the cables again.
17. When the cables are adjusted lock the nuts in place using the
second nut.
18. Apply the handbrake lever, you should hear 4-5 clicks. If more
clicks are heard then the adjustment is a bit loose, if less then you
must re-adjust the brakes to avoid glazing the pads.
19. Remove jack stands and lower the car.
20. Done!
Notes: If the parking brake is becoming less effective you need to examine it for 'premature' wear. Remove the pad and inspect it (you'll need to remove the bolt holding the adjustment cam and shim). If there is a shiny surface then you likely have a glazed pad. Use fine sandpaper to remove the glaze (and treat the pads as if they were new for a while).