It’s been at least five years since my emergency brake started getting stuck “on” if I left the car parked for a few weeks. Since I have drum brakes on the back, the brake cable is attached to a lever on the hindmost shoe which forces both shoes against the drum at the top, pivoting on the auto-adjuster. There are a number of standard ways to release a stuck parking brake: applying and and releasing the brake multiple times, lurching the car forward and back, bouncing the back corner of the car with the locked up wheel up and down, flexing the cable housing with your hand between the wheel and the spreader (where the main cable terminates and a shorter cable goes to each brake drum), rapping the backing plate with a hammer (but don’t bend it) and tapping the front of the drum with a hammer and punch if your wheel allows you access. If all of these things fail to free the emergency brake completely, you’ll know because the tire will drag, or the car will stop too quickly if you try to coast in neutral. You’ll usually feel slack in the first few inches of the brake lever if the brake isn’t released fully.
A final trick if the wheel does turn, but with a lot of drag, is to drive it around the block a couple times, stopping every minute or so to make sure it isn’t getting too hot (and burning your fingers if it is). But the time comes when none of these quick-and-dirty tricks work, and the only solution is to remove the drum and replace the brake cable and the return spring, which needs to be strong enough to pull back the brake shoes when the brake is released. The elegant (ie, proper) way to get the drum off is to back off the self adjuster screw through the access port in the backing plate behind the drum (over the axle and under the bleeder screw and hydraulic line). This almost never works for me when I need it, either the auto-adjuster is a little rusted or the force of the sticking emergency brake cable keeps it from wanting to turn. So my solution is to cheat, which risks damaging the seals on the wheel cylinder, but when I’m stuck, I’m willing to risk it.
With a drum brake system, the rear wheel is mounted on studs pressed through the drum. The drum is held onto the axle, a stub axle in the case of a front wheel drive car, by a bearing and a single large nut. The bearing is what keeps the drum centered on the axel and allows the wheel to rotate with the minimum of friction.There’s a keyed washer, sometimes called a thrust washer since the wheel nut pushes it against the outer bearing which is thrust against a tapered bearing race in the drum, and the wheel nut is locked from loosening up by a castellated retainer and a cotter pin.There’s no way to remove the drum without removing the nut on the axle, and no way to access the end of the emergency brake cable and the lever assembly without removing the drum. Also, with the outer wheel bearing removed, it allows the wheel much more play on the axle, and by tapping the drum with a hammer, you can usually get the brake shoes to retract a little, even if the cable remains jammed.
But the way to gain a mechanical advantage to pull the drum off of jammed shoes is to put the tire back on and shake it. You want to run at least two lug nuts up reasonably tight, because if you try this with loose lug nuts, you’ll damage the threads on the studs. Don’t go berserk on the thing or you could damage the wheel cylinder. The video to the left shows the wheel pulling off, along with the drum, and the shaking is important. If you just tried to pull the drum with a puller, you’d almost certainly damage the brake shoes, the drum lining, or blow the wheel cylinder. The shaking gets the shoes to retract a bit, where you’re dealing with a jammed parking brake or frozen pistons in the wheel cylinder. So below we have a typical drum brake system,mounted in place, and you can see all the grease on the axle from the wheel bearings contrasted with the rusty, dusty interior. The narrow sprint running horizontally just below the greasy axle is the emergency brake return spring, and after 22 years (in this case), it’s just run out of “oomph.”
The bright colored piece that looks like aluminum is the self adjuster lock. You can see that there’s a spring holding it down on the geared part of the self adjuster, and the lock keeps you from simply sticking a screwdriver in through the access port covered by the rubber plug (in the picture back a few squares), and backing off the mechanical spread of the shoes. I never have any luck backing off the self adjuster in emergency situations, even with the lock pushed back from the gear. The video below shows the hack way of removing the whole assembly from the backing plate after removing the retaining clips on the short springs that holes the shoes loosely against the backing plate. Drum brakes are an interesting and cleverly designed system that looks like it was thrown together, but has been in use for a long, long time, and usually provides a better manual emergency brake than you get with disc systems.
The next two videos show disassembling the emergency brake cable from the shoes, so it can be replaced along with the spring. In this particular instance, the spring is worn out and needs replacing, and the cable itself was a bit frayed going into the sleeve that brings it to the drum. The video to the lower left shoes removing the retaining clip or washer that holds the lever into the shoe assembly. It can be surprisingly difficult to get the lever out once the retaining clip is removed because the shaft can be oddly shaped. The video below shows how you slide back the spring on the lever so you can get the ball end of the cable out of the lever. When the spring is in good shape, it takes quite a bit of force to pull it back, and you may feel like it would be easier if you had three hands. In this case, the spring is so worn that it was the easiest part of the job. As soon as I get the pictures, I’ll show getting the brake cord out of the drum and the adjuster under the car. Replacing the cable is just a matter of reversing the steps.
The last steps in removing the emergency brake cable are unhooking it from the spreader, removing the retaining clip that anchors the sheath to the stub frame, and getting the spring and the cable end out of the drum. The first step, removing the ball end from the spreader that is activated when the driver pulls the parking brake lever up, doesn’t require illustration. The retaining clip pulled straight up from the the slot without trouble, even though it hadn’t moved since 1986.. What’s much trickier is getting the retainer out through the whole in the hub. In this case, it had three tabs sprung out to hold it in place, and the shop manual suggest using a small hose clamp to gather them it. I got two of the tabs started through with the baby visegrips, and then got them out of the way and poked the third on through with a screwdriver. On reinstallation, it’s a good idea to feed the cable with the ball end through the stub frame first, get the ball hooked through the spreader, and then feed the other end through the drum. After that you can install the outside retaining clip, then hook the cable up to the lever that gets reinstalled on the shoe.
You can see the new emergency brake cable and spring installed. I put it back together in reverse order of the video, starting by hooking the cable up to the lever, then installing the lever on the brake shoe, then installing the brake shoes on the backing plate. The problems cam at what should have been the simple end, hooking the new cable up to the emergency brake adjuster and spreader. The problem is that the slug on the end of the new cable wasn’t as wide as the ball on the old cable so it simply pulled through the hole. To kludge it, I forced it back into the slot section and filled the whole with a 1/4″ bolt. I didn’t realize until I got home and looked at the picture that cable slug is actually caught between the head of the bolt and the double nut. It works, but I think it will be a better fix if I reposition the end of the cable to be next to the bolt. Barring that, a washer or two wouldn’t hurt:-)
If It Jams Home | The Omni Project | The Rusted Unibody | Cutting the Subframe | Cutting Out Rust | Building a Unibody | Bolt Together | Floor Replacement | Replacing Inner Tie Rod | Replacing Emergency Brake Cable | Replacing Battery Ground | Replacing Car Exhaust | Make a Shift Rod Bushing | Bosch Solenoid Rebuild | Contact