How To Re-Assemble Your Drum Brakes
Q: Help, I took my rear brakes apart, and I can't figure out how to put them back together.
A: Wow, it sucks to be you.
Look at the brake shoes, one half of a pair will have a longer or taller friction material. Always remember large shoe to the rear. Now get your brake shoes into two pairs.
Now that you know which one is front, and which one is rear. Now which way is up?
There's a flat metal bar in amongst your parts. It might not be flat, it might have a little bend here and there, but the ends will be parallel and have a slot in each end. That piece is called a "parking brake spreader bar" and it's purpose is to activate the front brake shoe with your parking brake. Now find the oval shaped compression spring that goes over one end of it, you'll need it later. [ Diagram: park brake strut and spring ]
That flat parking brake spreader bar goes into a corresponding slot in the brake shoe. Look at the inside of the brake shoe, you'll find a square or rectangular notch or slot in them. Thats always at the top.
Cool. So now that we know which brake shoe goes where and in which direction. Time to put them back on. Put the front shoe on the backing plate first, it can be put on without much drama; theres nothing extra to add yet. Just push that nail looking thing with the weird non-pointy end on it through the hole in the backing plate, verify its the right hole by noting a hole in the same place at the rear of the backing plate. [ Diagram: hold down pins ]
Stick the brake shoe in place. There's usually a notch in the top to go around the wheel cylinder, or sometimes the pushrods coming out of the wheel cylinder have a slot in them to accept the brake shoe. Either way, it will be self-explanatory. The top of the shoe will always rest against something solid on the backing plate. Once the brake shoe is in place, the pin you pushed through the backing plate should come through a hole in the middle of the brake shoe somewhere. It gets fun now unless you have the correct tools.
Pick up one of those small round compression springs, and one of the funky looking washers with the slotted hole in them. [ Diagram: hold down spring and retainers ] Count how many of those washers you have, sometimes theres one under and one over the spring, sometimes just one over. Figure out how many you got and how many you need. Try and hold the brake shoe in place while also holding that pin through the backing plate and out the brake shoe. Stack one of the slotted washers on top of a spring and push it against the brake shoe, over the pin. Use needle nose pliers or the correct tool. Sometimes I use a nutdriver if it's more convenient to put enough pressure on that sucker to get the pin with the flattened head to come through that slotted hole. Then do some magic and turn the washer a quarter turn while holding the pin steady. This will lock the washer in place because the "ears" on the pin will lock into grooves on the washer, preventing it from turning.
If all went well, the brake shoe will stay in place now. If all went badly, you shot the spring and washer across the driveway and into the grass never to be seen again. Deep breath. Go to the parts store for a new brake hardware kit, repeat until you succeed or run out of new parts. If you know yourself to be clumsy, consider working with some kind of back drop or enormously fat friend behind you.
Now that was the easy part. Luckily, you took these brakes apart yourself, so you do remember some of it and its all coming back to you right?
Next, it's the rear brake shoe that needs to be installed. Whoooaaahhh, don't just stick it on, theres stuff thats gotta be done first. The parking brake lever. [ Diagram: park brake lever ] No, not the flat bar that we talked about earlier. That was the parking brake spreader bar. Now I'm talking about the funny-looking curved piece that the parking brake cable was attached to. It's probably stil attached to the cable cause you couldnt find the right combination of tools to tear it apart.
So you've now gotta put the parking brake lever back on the brake shoe. The lever has a pin at the top that will correspond with a hole in the top of the rear brake shoe (the larger one remember?). It goes in from the backing plate side of the brake shoe. Just look at it. You remember which side is the top now. There's two holes near the top; pick the topmost one and put the pin of the brake lever through it. Somewhere in your pile of indescribable parts is a clip of some sort that holds them together. Find it and install it. Whoohooo, now we're ready to install that rear brake shoe...as soon as you figure out how to hook the bottom of the parking brake lever back onto the cable. You're on your own on that one, they're all different. You took it apart, you'll figure it out I'm sure.
Now, stick that rear brake shoe in place, and pick up that flat parking brake spreader bar we talked about earlier. Carefully look at it and the spring that goes with it, and figure out how its gonna fit between those brake shoes. The oval shaped spring over one end is gonna go to the rear. It's there to keep tension on things so it doesn't fall out when you're using the conventional brakes. There will probably be a top and bottom, cause the bar will be curved to clear axleshafts or things like that. It'll really only fit in one way and there's usually a left and a right that are mirror images of each other. Good luck.
Once you figure out where it fits, stick it in the front brake shoe first and then put the rear brake shoe in place. Now with your three hands, again hold the brake shoe, the pin through the backing plate, the parking brake spreader bar, and install the round compression spring and slotted washer assembly. Don't lose them this time.
Whew, almost done. The brake shoes will now sit in place on their own. It's Spring Time. Geez that shouldn't have taken all winter.
Look at that pile of springs. There's a bunch, and they're all different colors. All those colors mean something but good luck remembering which is which. Most of the time anyway, they're gonna be the same rust color at this point. Sort them out. You should have six springs, three for each shoe. Okay sometimes you'll have more, but I'll just tell you what you need. Put the springs into matching pairs. Four of them will be similiar shapes, just two of them longer than the other two, and the last two will be really odd. Sometimes an "S" shape with hooks, sometimes a weird hook on one end that defies description. For now, we'll deal with the ones that are similiar.
There's a nice hook on one end, and the other end has what seems to be a hook bent the wrong way. It will all make sense once its installed. You now have two pairs of these. The shorter one is for the front shoe, the longer one is for the rear (see a pattern developing?) Now look at the front shoe, theres a hole in it near the top, kind of like the one you put the parking brake lever through, but lower down.
Stick the odd end of the spring in that hole, and then point it upwards and rearwards. Note the stud on the backing plate in the middle at the top. The brake shoes should nearly be resting on this, they just need a little spring to pull them tight towards it, and compress the pushrods on the wheel cylinders at this point too.
Intalling springs is always fun. Someone will get hurt. It might not be you, it might be the neighbor as your Vise Grips go flying across the yard. Get your favorite pair of Vise Grips, or the proper spring installation tools...or if you really want to put a gouge in your hands, a big screwdriver. You gotta pull, pry, pray, and get the hook of that spring over the center stud. Usually your Vise Grips will interfere with something the first couple times. Fun huh? Okay, got that done? Good.
Next, the rear top spring. There's a hole in the rear shoe in a similiar place, just below the parking brake lever pin. Now sometimes this also holds a fancy pulley of sorts that the self adjuster cable runs down, but I'm going to ignore that for now. You can live without it until you get a chance to seek professional help. So stick that odd bent in the wrong direction end of the spring in that hole, and install the other end on that top center stud just like you did with the front spring. [ Diagram: shoe return springs ]
Now wipe up the blood, wash your hands and put the brake adjuster back together. [ Diagram: adjuster screw assembly ] Its got a cap with a slot in it on one end, the other end has a slot in it as well, and the middle has threads and a toothed wheel on it. It should spin and get longer or shorter as you turn it. If it doesn't turn, get some penetrating lubricant into it and work on it until it will turn. After you break it, go buy a pair of new brake adjusters.
So with the brake adjusters assembled, you can now install them. Installation is easy. They go at the bottom of the brake shoes. There will be a flat spot or a corresponding slot in each one. It will make sense once you stick it in there. Of course, there's a front and a rear. Look carefully at the bottom of the backing plate. There will be a rubber plug in it, or at least there should be, theres either a rubber plug, or an oval shaped hole. Of course, there are some brake setups that dont have the hole, like Mazda Couriers and other odd things, and some of them have the hole in the brake drum, but for most aplications, theres a rubber plug in a hole in the backing plate. And it's offset to the rear, or on the odd occasion to the front.
The toothed wheel on that brake adjuster goes in front of that rubber plug, or hole if he plug is missing. Stick it in there between the brake shoes, and guess what? Spring Time Again!
For some reason, this spring is difficult for many reasons: you've got a parking brake cable in there, the parking brake lever, the brake adjuster, and the axle flange is also impinging on your line of sight unless you happen to have the vehicle on a hoist (and if that's the case, you've got no business taking advice from me).
Figure out which spring you need. [ Diagram: shoe spring ] It needs to reach from the hole in the bottom of the brake shoe to the hole in the bottom of the other brake shoe. If it's a nice spring in somewhat of an "S" shape, no problem: hook it under one brake shoe into the hole, and over the other brake shoe into the hole. If it's got a funky hook on it similiar to the upper springs, it goes in the same way as the upper springs, except that you just go across to the other brake shoe instead of to a center stud.
Look, you're done! Slap those drums on and put the wheels back on. Oh yeah, repeat for other side...and don't forget: front and rear have now changed position relative to your body position!
Of course, theres the matter of the brake self adjusters that could possibly be there. You might have this funky looking plate left over. [ Diagram: adjuster lever ] It's kind of got a hook on the left side, an oval-shaped hole at the top, and a flat edge on the bottom. Throw it over your shoulder. Okay, no don't do that. The hook deal should fit in the hole on the bottom of the rear brake shoe. That flat bottom should be horizontal and parallel with your brake adjuster, and if you can imagine it ratcheting up and down, it would turn that serrated wheel on the brake adjuster. So take the spring out of the hole at the bottom of the rear brake shoe, stick the hook of the brake adjusting, uhhh, plate thing, into that hole, and hook the spring into that oval-shaped hole at the top. Excellent, all done, except for the cable...
What? Cable? Crap, what's that for??? [ Diagram: adjuster cable ] Well the self-adjusting system is all very complicated and rarely works. But when it works, it works great. So the cable, it's got a round eye attached to one end, and a hook on the other end. Where does it go??? Oh boy, you're gonna love undoing stuff you've already done.
Unhook the top spring for the rear brake. Hook the cable eye over the center stud. Now, if you've got the cable, you should have a tin cable guide. It's got a nice slot in it, looks like half a pulley, and a hole at the edge of it. We briefly talked about it earlier. This goes in the hole that the spring was in. The cable groove faces towards the rear. Stick it in place and hold it there or it will fall out. Run your cable down from the top stud, over this cable guide, and down. Now stick the top rear spring in the hole and hook it back up to the top stud. Stop swearing.
Okay, one more step. You've just gotta attach the hook on the bottom of the cable to that oval-shaped hole in the brake adjuster plate thing at the bottom. You may have to unhook the bottom spring to make it reach. See I told you you'd love taking things apart again.
Thats it, slam the drum on, and you're ready to drive. Except for the brake adjustment. For that, look in your repair manual or something.
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