1 00:00:09,041 --> 00:00:09,375 Hello. 2 00:00:09,375 --> 00:00:09,791 Right. 3 00:00:09,791 --> 00:00:14,083 In this video, we're going to have a quick look at checking and assessing rear drum brakes 4 00:00:14,333 --> 00:00:19,250 and then the follow on parts of this video is going to be adjustment and setting up of the handbrake. 5 00:00:19,375 --> 00:00:21,041 Okay, the two jobs go together. 6 00:00:21,041 --> 00:00:23,291 They're not part of a standard service on a vehicle. 7 00:00:23,291 --> 00:00:27,500 It's generally every 50,000 60,000 miles for rear brake service. 8 00:00:28,125 --> 00:00:30,666 OK, so on the set up on this rig, 9 00:00:31,208 --> 00:00:33,791 we've got a rear hub nut which holds the drum assembly on. 10 00:00:34,000 --> 00:00:35,041 Some vehicles. 11 00:00:35,041 --> 00:00:38,875 The drum assembly itself is just held on by a cross headed screw. 12 00:00:39,166 --> 00:00:41,541 And then we can just tap it and free it off. 13 00:00:41,541 --> 00:00:43,125 OK, so first, job first. 14 00:00:43,125 --> 00:00:47,541 There's normally grease cap on top of this, we've removed that before we started. 15 00:00:47,541 --> 00:00:50,000 So hub nut on this one is 30 mm. 16 00:00:50,416 --> 00:00:52,125 So we've got a braker bar 17 00:00:55,083 --> 00:00:57,333 and 30 millimeter socket. So 18 00:00:58,916 --> 00:01:01,625 motor vehicle, they're right hand threat, 19 00:01:01,666 --> 00:01:05,708 some commercial vehicles, the near side rear hub is left hand thread. 20 00:01:05,708 --> 00:01:06,791 So just be really careful. 21 00:01:06,791 --> 00:01:09,083 If you're trying to undo one, it seems really tight. 22 00:01:09,416 --> 00:01:13,000 Check the thread itself is not a left hand thread on a commercial vehicle. 23 00:01:13,666 --> 00:01:16,708 OK, so we're going to slacken the nut off. 24 00:01:38,041 --> 00:01:40,041 Right, so the nut on this particular vehicle, 25 00:01:40,833 --> 00:01:45,333 it's got a clamp on the outside and it's actually a set of thinner nuts held together in a group. 26 00:01:45,541 --> 00:01:50,833 If this cluster is broken or they've become detached, its a lot easier just to replace the unit itself. 27 00:01:51,083 --> 00:01:55,958 Some French vehicles, if you take the hub nuts off, they're actually staked over and bent with a punch. 28 00:01:56,583 --> 00:01:59,166 You need to replace those every time you remove them. Okay? 29 00:01:59,375 --> 00:02:01,416 They're not supposed to be reused as an item. 30 00:02:01,416 --> 00:02:04,833 It's one shot and then you have to replace them as part of the kit. 31 00:02:05,500 --> 00:02:10,000 OK, so we remove the hub nut. We can spin the drum to see if it's fairly free. 32 00:02:10,208 --> 00:02:12,541 If it's lightly binding, that's fine. 33 00:02:12,541 --> 00:02:15,291 If we've got to put a lot of effort in to turn it, it's too tight. 34 00:02:15,541 --> 00:02:19,750 Likewise, if it spins really freely, then the brakes aren't going to engage soon enough. 35 00:02:20,666 --> 00:02:22,791 So soft face mallet. 36 00:02:22,791 --> 00:02:26,041 The drums are made of cast iron, so we need to be careful. 37 00:02:26,041 --> 00:02:30,375 We don't damage them, and then we should be able to rotate it and undo it. 38 00:02:30,416 --> 00:02:35,291 Just be careful when we take the drum off, your wheel bearing's fitted inside 39 00:02:35,291 --> 00:02:36,750 and some of them have got a rubber seal. 40 00:02:36,750 --> 00:02:38,791 If we damage that on there, taking it off. 41 00:02:39,125 --> 00:02:42,125 The grease will leak out the bearings and we'll be replacing them later. 42 00:02:42,500 --> 00:02:46,166 If we've got brake dust in here, we'd be using a face 43 00:02:46,166 --> 00:02:49,833 mask and brake cleaner just to kind of solidify. 44 00:02:49,833 --> 00:02:52,666 Obviously this unit's new so we don't have to worry about it. 45 00:02:52,666 --> 00:02:55,583 On this occasion, while we've got the drum off, 46 00:02:56,083 --> 00:02:59,250 check the wheel bearing by hand to check if it's smooth and secure. 47 00:02:59,500 --> 00:03:02,708 If there's a wear in there, I'd be replacing it. 48 00:03:03,333 --> 00:03:05,791 OK, the drum itself is also marked here. 49 00:03:05,791 --> 00:03:09,791 We've got a maximum diameter 204.3 millimeters, 50 00:03:10,041 --> 00:03:15,125 so we're measuring across there if it's bigger than 204, it needs replacing. OK. 51 00:03:15,333 --> 00:03:18,458 And as with the front brakes, if we're replacing one brake drum 52 00:03:18,666 --> 00:03:22,791 good engineering practice to replace the pair, so they wear together at the same rate. 53 00:03:27,791 --> 00:03:29,750 Right, so break shoes we've got wheel 54 00:03:29,750 --> 00:03:34,750 cylinder, what happens when I operate the pedal, if I go carefully now and just gently press it. 55 00:03:35,208 --> 00:03:37,291 We should see a bit of movement. 56 00:03:37,291 --> 00:03:40,208 OK, that brake shoe there is the leading shoe. 57 00:03:40,208 --> 00:03:42,333 It's the first shoe to touch the brake drum. 58 00:03:42,666 --> 00:03:45,375 When that contacts the drum this side then 59 00:03:45,375 --> 00:03:48,541 pushes on the other side and that's what engages your drum brakes. 60 00:03:49,166 --> 00:03:52,000 OK, so word of warning if you're pressing 61 00:03:52,000 --> 00:03:55,250 the brake pedal with the drum off, if you've got somebody sat in the car 62 00:03:55,250 --> 00:03:59,416 and they put their foot on the brake , it is possible to push these brake shoes right off. 63 00:04:00,041 --> 00:04:03,208 OK, if that happens, the piston falls out of the cylinder, brake 64 00:04:03,208 --> 00:04:06,208 fluid leaks all over the floor, air gets into the system. 65 00:04:06,208 --> 00:04:10,083 And then it makes a right mess as well, and we'll have to clean up and bleed the brakes. 66 00:04:10,458 --> 00:04:15,250 OK, so with the brake drum off, please ensure that nobody's touching the brake pedal in the car. 67 00:04:16,000 --> 00:04:19,958 OK, so we've got two pistons on wheel cylinder to check they're working. 68 00:04:20,333 --> 00:04:24,250 We can actually operate it with a screwdriver and just gently push it both ways. 69 00:04:25,916 --> 00:04:28,750 And we just see that little bit of movement there, backwards and forwards. 70 00:04:29,083 --> 00:04:31,291 That's fine, that's the pistons moving. 71 00:04:31,291 --> 00:04:35,250 These units aren't repairable if it's seized, damaged. 72 00:04:36,125 --> 00:04:40,416 Take it out and replace it and then perform the same checks on the other side. 73 00:04:40,666 --> 00:04:43,416 Generally, if one leaks, the other one is not far behind. 74 00:04:43,958 --> 00:04:47,000 OK, this is another reason to change your brake fluid every two years. 75 00:04:47,416 --> 00:04:51,083 OK, the system gets water in it and then corrodes from the inside out. 76 00:04:51,791 --> 00:04:54,666 OK. These are dust caps on the cylinders. 77 00:04:54,875 --> 00:04:59,166 So if we're very careful with the screwdriver, we can lever these back and just check behind. 78 00:04:59,375 --> 00:05:01,416 It should be dry. 79 00:05:01,416 --> 00:05:04,875 OK, if we've got signs of brake fluid on there or it drips out the bottom 80 00:05:05,375 --> 00:05:10,250 that clyinder's leaking and needs replacement, OK, it's not worth putting it back together. 81 00:05:10,583 --> 00:05:15,208 If the cylinder leaks, it will contaminate the brake shoes and then we'll have to replace the whole set anyway. 82 00:05:16,000 --> 00:05:18,333 OK, so we can check both sides. 83 00:05:21,375 --> 00:05:22,625 Yep, that's right. 84 00:05:22,625 --> 00:05:24,958 That's okay, we can refit that. 85 00:05:24,958 --> 00:05:28,333 OK, so inside the break shoes itself, 86 00:05:29,791 --> 00:05:32,750 we've got the friction material again bonded on 87 00:05:33,000 --> 00:05:35,541 some units, they're riveted on the sides. 88 00:05:35,791 --> 00:05:41,291 What happens is if you wear that material out is the metal in the rivets, contacts the metal on your brake drum. 89 00:05:41,708 --> 00:05:44,375 They work exceptionally well, but 90 00:05:44,375 --> 00:05:47,625 very noisy, and it does wear the brake drums at a high rate. 91 00:05:48,250 --> 00:05:51,958 Okay, so we're checking material, same as the brake pads, we're checking for damage. 92 00:05:52,125 --> 00:05:55,291 If it's become unbonded, it's a replacement, OK? 93 00:05:55,458 --> 00:05:57,833 They come as an axle set in a box. 94 00:05:58,166 --> 00:06:00,125 Okay, don't ever replace one side. 95 00:06:00,125 --> 00:06:01,750 You must replace both sides. 96 00:06:01,750 --> 00:06:04,000 It is good engineering practice. 97 00:06:04,000 --> 00:06:08,875 OK, we've got retaining springs and we've also got the adjusting mechanism in the center. 98 00:06:09,458 --> 00:06:11,708 OK. It's semi-automatic. 99 00:06:11,708 --> 00:06:16,208 The idea is when you press the brake pedal, the adjuster moves out, takes up the slack 100 00:06:16,208 --> 00:06:19,958 and then holds it in that position so it doesn't have to adjust every time. 101 00:06:20,875 --> 00:06:23,625 Common complaint from customers is that the brake pedal 102 00:06:23,625 --> 00:06:26,791 takes a long way to press down before it operates correctly. 103 00:06:27,000 --> 00:06:30,458 This is usually due to rear drum brakes not being adjusted. 104 00:06:30,666 --> 00:06:32,750 Fronts are properly self-adjusting. 105 00:06:32,916 --> 00:06:35,375 Rears do need servicing and checking. 106 00:06:36,375 --> 00:06:37,583 OK, so 107 00:06:37,583 --> 00:06:43,083 we can have a look at that. General condition's good in here, retaining springs are on nothing's adrift. 108 00:06:43,083 --> 00:06:47,291 If we were replacing these shoes, we'd remove these clips, take the pins off 109 00:06:47,291 --> 00:06:50,916 and then we can unhook the shoes from the backplate, which will run through in another video. 110 00:06:52,125 --> 00:06:54,375 Handbrake cable. Now this is very important. 111 00:06:54,375 --> 00:07:00,291 Handbrake Cable sits in the bottom of the drum and operates this lever on this rear shoe only. 112 00:07:00,583 --> 00:07:04,750 So if I operate the handbrake lever gently, you should be able to see 113 00:07:04,750 --> 00:07:06,583 movement inside. 114 00:07:08,333 --> 00:07:10,208 OK. Handbrake is self-adjusting, 115 00:07:10,208 --> 00:07:14,291 the cable, which will run through the next video, operates on a self adjuster 116 00:07:14,583 --> 00:07:18,583 and it will compensate for both sides to make sure that they're operating correctly. 117 00:07:19,208 --> 00:07:20,750 OK. Handbrake lever. 118 00:07:20,750 --> 00:07:23,000 When we go to reassemble this, we'll be checking. 119 00:07:23,000 --> 00:07:26,833 But this lever must fit against the stop in the backplate. 120 00:07:26,833 --> 00:07:29,875 It's very important if it's not sat flush against there 121 00:07:30,125 --> 00:07:35,041 it's already operating the brake before we've adjusted it, and your adjustment will be incorrect. 122 00:07:36,000 --> 00:07:37,041 OK, so 123 00:07:37,041 --> 00:07:42,041 we've checked the piston, we've checked the connections on the brake shoes themselves. 124 00:07:42,250 --> 00:07:45,291 We've checked the handbrake cable is securely fitted in the back plate 125 00:07:45,291 --> 00:07:48,750 and the spring works we've checked the lever is up against the stop. 126 00:07:50,500 --> 00:07:55,333 Hydraulics wise, we've got brake hose set up on the back here, the same as the front. 127 00:07:56,333 --> 00:07:59,041 So the white line of paint applies to hoses. 128 00:07:59,291 --> 00:08:02,291 Any hose damage replace is a matter of urgency. 129 00:08:02,291 --> 00:08:04,750 Don't reuse old hoses. 130 00:08:04,750 --> 00:08:09,166 OK, and then we've got a copper pipe, which runs up to the actual cylinder itself. 131 00:08:10,291 --> 00:08:12,500 OK, if any of these items are rubbing 132 00:08:12,500 --> 00:08:15,875 against the vehicle needs rectification urgently. 133 00:08:15,875 --> 00:08:20,583 OK, otherwise there will be fluid loss in system can lead to a loss of the braking system. 134 00:08:21,625 --> 00:08:26,375 OK, so when we're putting this back together, we'll check the drum itself. 135 00:08:26,916 --> 00:08:29,416 There's no undue wear in here, 136 00:08:29,416 --> 00:08:31,708 so there's no lip on the edge of the drum. 137 00:08:31,708 --> 00:08:34,458 We've measured the diameter. It's within specification. 138 00:08:34,875 --> 00:08:36,916 So what we can do is we can refit this. 139 00:08:39,458 --> 00:08:41,625 So it should be a nice kind of push fit. 140 00:08:41,833 --> 00:08:46,458 We have to put a bit of effort in if it's too loose, that's not a problem because we can adjust it. 141 00:08:46,708 --> 00:08:49,541 If it's too tight to put the drum on, don't force it. 142 00:08:49,708 --> 00:08:54,291 You will damage the brake shoes and then we'll have to take it off again to kind of refit it. 143 00:08:54,750 --> 00:08:59,125 So just a gentle turn just to make sure it's kind of fitted in. 144 00:09:01,041 --> 00:09:02,083 Replace the hub nut, 145 00:09:02,083 --> 00:09:05,958 if it's serviceable, if it's not, and as I said before, will have to change that. 146 00:09:06,916 --> 00:09:09,083 OK, so we can run it up by hand. 147 00:09:09,083 --> 00:09:11,750 What I would suggest is running it up by hand and tightening 148 00:09:11,750 --> 00:09:14,875 it, doing your adjustments and then retorquing at the end. 149 00:09:14,875 --> 00:09:19,291 Otherwise, if we torque the nut and then have to take it off again, it causes undue wear. 150 00:09:27,125 --> 00:09:27,625 Right. 151 00:09:27,625 --> 00:09:28,916 So that's fairly tight. 152 00:09:28,916 --> 00:09:32,791 Just kind of hand tightened, soft faced hammer again to centralize everything. 153 00:09:36,625 --> 00:09:39,208 And that now just turns with some light pressure. 154 00:09:39,708 --> 00:09:41,916 OK, if it's slightly binding, that's fine. 155 00:09:42,208 --> 00:09:45,708 If it's too tight, then we'll have to remove it if it's too slack. 156 00:09:45,875 --> 00:09:49,208 We can now adjust it by pumping the brake pedal itself. 157 00:09:49,708 --> 00:09:52,208 So if we pump the pedal a couple of times 158 00:09:52,208 --> 00:09:54,833 and then not now will centralize that, 159 00:09:55,458 --> 00:09:59,125 and then we can proceed on to adjusting the handbrake itself . 160 00:09:59,125 --> 00:10:01,875 And in the next section, we're going to run through adjusting the handbrake 161 00:10:01,875 --> 00:10:05,333 and checking that the operation is correct and it's set at the correct height.