About a year ago I repaired my emergency/parking brake on my 96 ZJ and have been meaning to do a write-up. This is for rear disc brakes with a cam/lever system for pivoting/pushing out the ebrake shoes and not for full shoe drum type rear brakes on earlier years.
I've found some other ebrake write-ups around which involve cutting or chiseling the cam/lever out and may have come up with a better method. This involves the use of 2 pairs of med/large size vice-grips for prying the seized cam/lever apart. You should be able to salvage them to avoid these pricey parts but since I already bought new cams & levers I went ahead and installed them. And there's no need to remove the rear axles as stated in the FSM to do this repair.
If you live in the salt/rust belt you're more apt to have the cams/levers seized together and with only one small ebrake shoe working on each side it's about impossible to hold/stop a ZJ. Many will try to adjust the tensioner tighter where the 2 ebrake cables come together under the middle of your ZJ but this is factory pre-set. It should never need adjusting unless you replace the cables themselves or disconnect it.
Enough gab, the photos with explanations start with removing the cam/lever but will offer instructions from the onset.
1. Do one side at a time. Block front wheels, make sure ebrake is off, start jacking up, loosen lugs with tires on the ground, jack fully up, install jackstands, remove wheel.
2. Remove caliper by prying out from top and hang from top of spring with wire or tie. Caliper bolt heads can be 13mm, 1/2" or other sizes if replaced before.
3. Spray rust cutter on rear hub where rotor fits on and you may need to sand the rust off the hub 1st. I've also used a razor knife tip to break the rust seal. While many try to pound the rotor off from the backside it's better to install the lugs on loosely then hit it with a big hammer on the front around the studs to pop it loose. The lugs just protect the threads in case you hit a stud.
4. Once the rotor is loose if it won't come off the ebrake shoes may be holding it on. Remove rubber plug in back/bottom and use a screwdriver or brake lever tool to loosen adjuster. You should stick the tool in angled at the top and rotate down to loosen the adjuster.
5. With rotor off you may want to draw a diagram of the spring and adjuster position or take a photo. Don't take all the springs/adjusters off both sides at once unless you know exactly where they go. It's best to lay the springs/adjuster out as they came off on the old shoes. You can use the brake parts on the other side as a reference.
6. Remove the 2 springs and the adjuster. Then hold the back pins with your finger while you remove the front clips from the shoes. I've found a pair of needle nose vice-grips are about the best tool for removing the springs and the clips.
7. Remove the eyelet on the brake cable behind the dust shield from the hook on the end of the lever. Spray the cam/lever down really thoroughly with rust cutter and it's best to let it soak as long as you can. I used to use PB all the time and just switched to the acetone/ATF mix which seems to work better.
8. Adjust your 1st pair of vice-grips and snap it on the cam real tight as can be seen in the below photo.
9. Take your other pair of vice grips, turn them upside down, and snap them on the lever real tight.
10. Vice grips should be positioned on cam/lever as below and start working them up/down in opposite directions while continuing to spray rust cutter between them.
11. It will take some serious prying up/down to break the pin loose between the cam/lever but they can take it since they're made of thick metal. Below the cam is finally loose and it will come out towards the back as you work it around.
12. Both the cam/lever are being removed from the backside behind the hub.
13. Below are the new cam/lever but like I said before if you had a good wire wheel on a grinder you should be able to clean those old ones up. I applied white/lithium grease to where they meet and anti-seize on the pin since that's what tends to corrode/seizes the worst.
The cam fits either side, OE part #4762132, $8-$20 at the dealer.
Right side lever, OE #5179290AA, $23 at dealer.
Left side lever, OE #5179291AA, $23 at dealer.
Here are how they are positioned before being installed.
The lever being installed.
And after both the lever and cam (which is on top) are installed. Note: there's a little meal shelf on the dust cover these ride on. Make sure it is bent back up to stick straight out because it may have been bent slightly down when prying out.
14. After cam/lever are installed connect the eye on the brake cable to the back of the lever. The hook on the lever will always point towards the rear when installed correctly.
15. On the dust shield there are small raised pads the ebrake shoes ride on. Sand these pads off smooth and put some white grease, or brake grease, on them. The shoes will hang up if you don't and both shoes won't be traveling out together. Note the anti-seize I put on the hub so the rotor doesn't rust on but don't get any on the stud threads.
16. With the shoes in place this top spring is a bear to get on with needle nose or pliers with the hub in the way. I found when using the sharp end of a chain saw file this hook on the spring went directly in the hole in the shoe every time. I would wear safety glasses when doing this since not sure about the file breaking and an awl may work too.
I also installed new shoes shown in place with the new top spring attached.
17. These are the needle nose vise-grips I use for putting the spring clips on and clamp them on real tight on the top part of the metal before even holding them on the pin.
18. View of the bottom spring and new self adjuster installed correctly. A new spring kit with self adjusters for both sides is only about $10.
19. After everything is installed pull the lever on the back where the cable attaches and make sure both shoes are moving out together. When installing the rotor just slowly start turning the adjuster a little from it's shortest length before even putting it on. You'll have to have it in neutral to spin the wheel so you can hear if the shoes are dragging on the inside of the rotor drum. Then just pull the rotor back off, adjust it out a little more, put the rotor back on, and keep doing this until you just hear it slightly touching the inside of the drum. Also check to see how tight the ebrake lever is while adjusting this.
Maybe after you drive it a little the ebrake will need adjusted again. Keep in mind if the adjuster is installed correctly to tighten it put the screwdriver or brake tool in the bottom of the slot and rotate the star-wheel on the adjuster up.
Hope this thread helps some and sorry about the length. Some say you don't even need an ebrake and they don't use one. But if you have a brake line blow or something else goes wrong you'll find a working emergency brake comes in real handy.