How To Replace Rear Brake Drum Backing Plate 1992-99 GMC K1500

Once you have your vehicle raised and supported, we're going to remove the center cover and the lug nuts behind it. Use your 22-millimeter socket. The next thing you're going to do is remove your drum. There's a couple of things that you may or may not have to do. One would be, of course, spray the area with some penetrant around the areas of the studs and the center area. There's also going to be an adjustment that you can relieve on the backside in case your brakes are overadjusted, and there's a lip on there. But for this one right here, it kind of just pulls right off. We'll take a peek and make sure you dispose of that brake dust properly.

The next thing we're going to do is grab onto this spring right here and draw it towards the shoe to get it out of the mounting area. Just carefully try to separate these shoes a little bit. This is moving around. If you wanted to, you can de-adjust this right here to be able to slide this out, but I'm just going to wait a second. And what I'm going to do is I'm going to grab onto this, slide that off of there, get a little spring, grab the spring out of there as well. Let's get this piece off of here. There's a little pin that goes straight through the backing plate. So, we're just going to kind of push on this, twist it, try to line up the slots on the cap, and the pin itself.

I'll show you exactly what I'm talking about. So, you have your pin. You can see it's got a flat edge. It's got two little hookies on it. Then you've got this right here. It would slide over the pin and then twist and then lock right in. Let's go ahead and get the shoe off of here. We'll get this out of the way, set that aside so we can clean it. We got a little spring down here, just go ahead and take it out of the shoe. Let's go ahead and get this shoe off of here as well. There we go.

The next thing we're gonna do is grab onto right here with some pliers. I'm going to use my cutters, but I'm not actually gonna physically cut anything here. I'm just using them for grip. I'm gonna try to get underneath this spring, in between the bracket and the spring. Next, it's time to get our emergency brake cable out of the backing plate. You're going to notice it has three prongs on it. You can try to grab onto all those with something as simple as pliers or you can get yourself one of these tools. Slides right over the cable, pushes in on all those tabs at the same time, hopefully, and then theoretically, you should be able to get your cable out.

If you look on the rear of the backing plate, you're going to see where your line goes into the wheel cylinder and, of course, your bleeder screw. Go ahead and spray down that area and let it sit. If you feel right along here, you're going to find your rubber brake hose in the rear. I'm just gonna go ahead and pinch that off with some wire pliers here. Obviously, you don't want to crimp it with a needlenose pliers or anything like that or locking pliers. Now that we've let this sit for a while, let's go ahead and use our 3/8 wrench and see if I can break this free. Nice. I'm just going to remove that line completely now. Your line fitting might be a different size, by the way. All right. We've got that out of there. Set it aside so it doesn't leak down anywhere.

Now we're going to remove the bolts that hold the wheel cylinder to the backing plate using a 10-millimeter. At this point, the wheel cylinder should come free. You can give it a loving bonk or pry it away. Just feel around on your backing plate, you're going to find these little rubber plugs. I like to save them. Next, it's going to be time to drop your rear differential cover. You're going to want to make sure that you have your hand protection and eye protection, of course, still, and you're going to want a catch bucket because inside here, there's going to be a lot of gear oil and it needs to go somewhere, preferably a collection bucket.

Before we drop it, go ahead and clean down the areas, especially where the pan is gonna mate onto the rear differential because the last thing you want is any crud getting inside there. The next thing you want to do is take a look at all these bolts and see if they look like they're rust and rotted. You might need to just put your socket on, give it a couple of taps and that should just break away the majority of the rust. Once you've done that, you would continue on with your 13-millimeter socket and remove all these bolts. Just take one of those little bolts, start it in there, a few good threads. The next thing we're going to do is break this pan free. Of course, fluid's going to come out, make sure you have your collection bucket.

We're just going to turn that driveshaft until we can see this bolt right here. This bolt comes straight through and it holds this pin in and the pin holds those little U clips that are in there holding the axles in. So, first we'll take out this 8-millimeter bolt and then be careful because this will just slide right out. Once that's out of the way, we'll push in the axle. I'm holding the pin so it can't slide out. The pin has hardened steel so if it hits the ground, there's potential that it could break. Slide that out. We'll put the pin right with it and we'll set it aside. And now we're just going to spin this a little bit more so we have clear access of the inside here. I'm going to go over, I'm going to push the axle, and watch right here, this clip is going to come dropping out. This looks great. There it is.

It's time to get the axle out of here. Make sure you have a nice catch bucket to catch any fluid that might come out. There it is. Now, I'm just going to carefully take a rolled-up rag, slide it in here to try to keep any of the crumbs that might fall in. Go ahead and spray these down. Use a 15-millimeter socket on the backside here, hold right on that nut and use another 15 on the front, remove the bolt. And there we are. Awesome. Do the same to the rest. There we are. Let's get this right off of here.

Now we're just gonna spend a little bit of time smoothening this out. That way there, we have a nice area for the new backing plate to go onto. Now that we have this area nice and cleaned up, we're just going to add a little bit of grease lubricant. You can also use copper Never-Seez, but it's a good idea to use something that's going to help keep the moisture out from in between the new backing plate and this area. Let's get these bolts on. I'm just going to put my washer right on the bolt, put it through, and the nut on the backside. I'll do the same to all. Let's snug this up and a crisscross manner.

Make sure you clean down your axle shaft and then especially right down here, this is where the seal's going to ride. Nasty. Go ahead and pull this out of here. Take a quick peek. This looks good. We're just going to add a little bit of gear oil right inside here, and we're gonna spread it around in those bearings. For this application, we're going to be using 80/90. Put that right in there. Make sure we got our catch bucket. Once you have plenty of gear oil inside, just kind of rotate it around and around and around. You want to make sure all of these bearings in here are sufficiently coated. Feels pretty good. If you want to add a little bit more, that's fine. Some people will say to keep adding so that way there it goes down the tube. That's completely up to you because once we're done or when we're getting closer to being done, I'm going to show you how to fill this tube anyway.

Let's grab the axle. We're going to carefully slide it in because we don't want to disturb that new seal. I'm just gonna wiggle it around. At this point, it's down by the differential and it's starting to go in down there. Okay. It felt like it stopped. I'm just gonna go back a little bit, turn it, and keep trying until it wants to slide into those spider gears. That's good. I'm just gonna go in a little bit. Now, we'll go into the differential and we'll put in that little C-clip. We've got our little C-clamp here, you slide it right over that area of the axle, and then slide the axle back out, that locks it in. We're gonna do the same to the other side, and then we'll put in the center piece. Clean your pin and inspect it for damage. Install the pin with the holes facing there. Grab your locking bolt with some blue threadlocker. Tighten this bolt. Torque this to manufacturer specifications.

So, now we're just going to cover these gears with something so we don't get any of this gasket on it or rust. Put that over it. Go ahead and use your scraper, and that's the stuff we're going to get off. We're going to make sure that this is nice and clean back here. So, once you get the majority of the large chunks off of this so you have a nice, smooth surface for that diff pan to ride on, you want to do the same to the differential pan itself. So, you can get this right here. You want to make sure you get off all these crunchies, make this nice and smooth. And, of course, if you want to clean down the backside, it's probably a great idea as well. I'll get this cleaned up and then we'll move along.

Okay. So, once you've got it nice and cleaned up, we're going to continue on with some gasket maker. I'm going to go right along here. It's important to use stuff that's oil-resistant. You want to make sure that you go with that, of course, inside the rear differential is oil. That looks great. So, now we're just gonna look up in here. We remove our rag, of course. Just take a double-check, make sure we tightened up that bolt, we've definitely got our pin in there, we got all the fluid out as much as we could. There's barely anything in there if anything. You want to make sure that you clean down around this whole area, make sure that there's no oily residue on any of this because if you do, the RTV or gasket maker isn't going to stick to there.

If you have a magnet, it's gonna go right on this little piton right there. You could see there's a little bump-out on the differential cover. It would sit right there. Just be a circle, look like a donut really. Once you put that magnet on, assuming you have one, you're going to go ahead and line this up. Make sure you put the bumped out area of the pan cover towards where the pinion gear is. Okay. So, we've got them all started in. If you have any of those tags, it's a good idea to make sure you put them back on. Anywhere where you see one of these little cutouts on the differential cover is a perfect spot. You have one right here and you have one right there. Let's go ahead and snug these up.

I just like to double-check these with a ratchet just to make sure they're all nice and snug. So, now it's time to fill up the rear differential. You're going to use plain old 80/90 gear oil. And when you fill it, you want to try to come up to just below that fill hole, maybe about a quarter-inch. Okay. I'm just gonna stick my finger in and give it a little curl to see. There it is. So, I went in, I just went down a teeny bit, about a quarter of an inch, and I'm right there. Perfect. Make sure you go ahead and put that plug back in. All right. So, now what you would want to do is just clean up the whole mess.

Okay. So, now that we've got this nice and tightened up, it's important to remember if you used the gasket maker, like I did the RTV, they recommend you waiting for approximately 24 hours before adding any oil to the system. If you're using a regular paper gasket or even cork, you're okay to go ahead and add oil right away. Let's get our wheel cylinder in here. Make sure that you get your little plug out of there. The bleeder screw is going to face up towards the top. Let's do that again. Let's get the wheel cylinder in there. Make sure you've got the bleeder screw facing towards the top, and you've got your rubber plug out. Put that through the backing plate and grab your two bolts. Start them both in before you tighten either of them down. All right. Let's snug it up. I'm just gonna double-check to make sure they're nice and snug. Awesome.

Let's grab our brake line, make sure no dirt's gotten inside here and the threads look good. Let's get it into the wheel cylinder. It's nice and snug. Perfect. Just take a little bit of lubricant, go right around your wheel cylinder. Let's get the emergency brake cable through here. Make sure it's secured in the backing plate. Now it's going to be time to push the spring back up the cable. To do that, Just use a set of pliers, bring it up to pretty much the edge of where that is, grab some cutters because that's going to be the easiest thing to grab onto this line, but you definitely don't want to squeeze to the point you break the cable, of course. We just want it to grab on. Just like that. I'm going to hold it, got this, slide it right on through, release that spring. This can come right up here like that now. It's looking great.

Let's grab our pin, our spring, and our cap. Put our pin through facing straight up and down, got our little clip here, get the spring on top. Just slide this right in. Let's try and get this stuff all lined up. Give it a little twist. Perfect. Let's get our long spring in through here. Got our adjuster here, you've got your wide end and the narrow end. We'll put the wide end through on the side that has the E brake pivot. Now I'm going to grab our spring, start it into its hole there. At this point, you want to be careful because you don't want to push through your wheel cylinder from one side or the other. So, I usually just try to come out at an angle, I'll line this up, and pull it through. Here we are. Rest these where they belong. That looks decent. Let's get the other pin in here. There we are. Get that spring on there. Let's get this lined up.

Now, this little dongle right here is going to go right down near the end and then you've got the hole, that's going to go over that roll pin. Let's get it in. Slide that there. All right. That looks good. Let's get the spring on there. Nice. Let's get our spring on here. Slides right in. Just make sure they're completely in. Perfect. Just give the shoes a couple of bonks. This is just gonna help make sure they're situated. If it seems like it's not resting against the backing plate properly, just look right down here. There is a little edge that it could go off the side of which, of course, will make the shoes sit awkwardly and the drum won't go on right. This looks perfect.

Now, it's time to clean up the mating surface from the axle to the drum. Now that we have this area cleaned up, let's go ahead and hit it with some copper Never-Seez. That looks great. Grab your drum, slide it right on there. As you could tell, at this point, it's super loose. If you wanted to, you can adjust it up a little bit to the point where it's at least close. And then, of course, I would start a couple of lug nuts on here and we would continue on from there. What you want to do is take your pry bar and go right in between the wheel cylinder and your adjuster right there and turn that wheel. As you hear it clicking, it's adjusting out. Go ahead and keep trying to put your drum on until the point where it feels like it's fitting on a little snug. Let's put this.

All right. Let's get the wheel back on here. Start on all of our lug nuts and then we'll snug them up. Let's torque them to manufacturer specifications. Now it's time to torque these lug nuts to 120 foot-pounds. We're gonna go on a crisscross pattern. Torqued. All right. Let's take our covers. Get those mounted on here. Perfect. So, now, it's going to be time to check and fill your DOT 3 brake fluid. To do that, you would just grab these little tabs, you can lift right up, lift up this little rubber, look inside. If you needed to add some, top it off, get it up to where the level says right along the side here. Once you know it's full, make sure you get this rubber back on the cap. Make sure it's nice and secure. Wipe down the area, and take it for a road test.