When you set up the calipers you should do them both as a pair. This is to ensure the e-brake cables share the same load and the mechanism is in phase side to side. There are a couple of simple things to check out to ensure it all works out ok. I'd even try this first before getting another caliper as 99.99% of the time I've found other issues to be the pain first.
1) Get the centre console out of the car. With the e-brake on is the spreader bar on the cable level? Do both cables pull the same?
2) Get the back in the air Both sides at the SAME time and get the wheels off.
3) Choose a caliper and remove it from it's bracket, then remove the bracket from the arm. Need the e-brake cable disconnected at the arm end too.
Check:
i, Do the pads look evenly worn?
ii, Do the pads slide FREELY in the bracket?
iii, is there lots of corrosion around the place on the bracket?
iv, If so ensure you scrape the edges of the pad ears, the slots they fit into, the rattle shims that clip to the brackets. You are done once the pad slips in with light finger pressure and moves freely with light finger pressure.
v, Check the slide pins and the slide pin bores. these should also fit cleanly and move with light finger pressure. If not these need cleaning too.
NOTE: Compacted rust is very hard and black, you will need a file or a tap to shift it. I generally use a file to break the surface for the ears and an M8 tap for the holes.
4) Once cleaned copper grease all the working surfaces (make sure there is none on the face of the pads. and bolt the bracket back.
5) repeat for the other side.
6) Caliper time: Wind the pistons ALL the way back until they bottom. If they are stiff or reluctant or the calipers are old you may want to rebuild the seal and piston interface too.
a, Wind out the piston.
b, remove the boot CAREFULLY (Little snap ring in the lip)
c, remove the square seal CAREFULLY ( I use a 2mm flat blade screwdriver.)
d, Wipe the boot and set aside.
e, Wipe the square seal in fresh brake fluid and set aside.
f, Now you need a funky little hook tool to clean out the seal groove. I make these from a portion of a wire coat hanger. Important thing to do is make a handle and a straight hook that will fit into the groove. Once done peen the tip flat so you can scrape the sh*t out of the square seal groove and the boot groove. You will be amazed at the sh*t that comes out.
g, next use the side of a flat screwdriver to scrape the sh*t and corrosion off the outer land of the seal groove (the bore between the square seal and the boot. Again, compacted rust is strong and you will be able to be quite hardy with this. You'll be surprised at the crap again.
***DO NOT TOUCH THE BORE INBOARD OF TYE SQUARE SEAL***
h, Reassemble the caliper and wind the piston right back.
7) Do the other caliper.
8) Assemble both back to their brackets DO NOT CONNECT THE E BRAKE CABLES.
9) Bleed if calipers were stripped or if preferred.
10) Get in the car and stamp hard on the brakes a couple of times to seat the calipers and pads but most importantly re adjust the e brake worm system IN phase.
11) slacken the e brake cable adjuster inside the car.
12) reconnect e brake cables.
13) Re adjust adjuster in the car.
When the e brake is operated the system should now be balanced. The toggle arm inside should be level.
14) Adjust now till drag is felt and then back off a1/4 to 1/2 turn. Should get a good number of clicks now.
15) Put wheels back on.
16) Enjoy.
Hope this helps
Rich