This is a step by step album on how to disassemble, rebuild and adjust the brakes on Dodge M37, 3/4 WC and 1946 - 1968 Power Wagons.
Album by Kevin Foust. 1 - 39 of 39 Total. 5630 Visits.
1 To get started I generally break the lugs free while the truck is on the ground, then jack it up. Remember that the "passenger is always right" hand thread and the "driver (side) is left. Do note that sometime they get replaced with different studs. If it seems like you are tightening it, you may be. On the rear I block the axle so both sides are in the air so you can easily spin the hubs once the tire is off. If you don't have good jackstands, cut a couple of large round pieces of wood from a tree and stand them on end.
2 Once the tire and rim are off you need to clean as much as you can off. Clean out the 3 slotted screws and the area between the axle and brake drum. Pointing to that area here and digging it out with a scribe.
3 I like cleaning the flange off too so the rim will slide off easier.
4 This is what you are looking for.
5 I then spray some penetrating oil in the and let it soak for a while. spin it a little and repeat a few times. May not do a lot but every little bit helps.
6 Close up of the cleaned up slot screw. Spray oil has a hard time doing anything here so I feel there is really no need.
7 Not required but I like to pound a few time on the head with a brass drift. Theory is it will jar it some but may be wishful thinking too. LOL
8 To help the tools life and your sanity, this is the easiest method I've used. I was using the tool without heat with good luck but came across a tough one and it broke. From then on. I heat the slot screw head to cherry red. Make sure not to distort/melt the slot. You just want it red hot.
9 Then use a wet rag to cool it off quick. the expansion/contraction normally makes it come out a lot easier. I did this on the tough one that broke the tool and it broke free with just a tap on the hand impact.
10 If you don't have one of these, I'd highly suggest getting one. Gentler than an air impact and I've had real good luck with it.
11 I made up this tool in order to use the hand held impact. I have these for sale. It has a 3/4" hex on the end so you can use a standard socket to drive it.
12
13 Got them all out with little to no damage.
14 The three holes in the drums face are to basically jack screw the hub off. You want to chase the threads first with a 3/8" course thread bottoming tap. Then you want to clean around the 5 wheel studs.
15 Slowly screw the bolts in till they are snug. Apply even pressure till they have equal tension.
16 If it doesn't pop free, tap with a hammer on the flat sections of the drum. You don't want too much tension as you can strip the threads out, Sometimes heat around the wheels studs is needed to break the rust bond/build up.
17 Once the drum is off You'll need to get the spring off. I brake tool makes it a LOT easier but it can be done with other things. You'll just be using some words that won't be said on Sunday!
18 To release the spring without the correct tool, You can use this set up. Easy to get off but a lot harder to get back in doing it this way.
19 If you are changing the wheel cylinder, I next take off the brake line and the 2 bolts on the back side that hold it there. You'll need a 1/2 wrench. Use a box end or 6 point to save rounding it.
20 Shoes are normally stuck and the lower adjustment bolts were seized on this one. If you're replacing the shoes, beat them out of the way like is shown. You can see these are gone as they have delamed and there is no material on there. They were not riveted.
21 Now it should come out.
22 Next take off the lower adjustment stud nuts. I think they are 15/16 from memory. These were seized so nothing on the other side was needed. There is a flat on the adjustment side stud and you can use an offset box end if needed.
23 Try tapping on the flat side of the stud or turning the adjustment. If it stuck hard don't mushroom the end by beating on it. Heat it up red hot from the shoe side and cool down with wet rag like the screws. You'll burn out the leather seals that go in the holding washers shown but they are normally junk anyway. You can either recut some leather or I like to use really large O rings that completely fill the space. they are like 3/16" in diameter and the studs OD.
24 It's a real good Idea to chase ALL the threads on all your fasteners. It'll make reassembly a lot easier for you. Take the time and you'll be glad you did.
25 You want to clean up all the offsets on the shoulders as well. This too makes the adjustment a breeze. Sandpaper or a fine file will do.
26 This is what you want to see.
27 Especially with new shoes you want to do this. They generally have burrs that you need to file off and smooth more with sandpaper. Once you do that, test fit the adjustment stud in there to make sure it moves freely.
28 Use some penetrating oil on the upper adjustment cams. I believe it takes a 1 1/16" socket from memory. Spin it completely around a few times till it's smooth. Then put some normal oil on it
29 Clean the lower holes out too with some sandpaper. I put the adjustment pins in there too for a trial fit. Once again, make sure it turns nice.
30 Use antisieze on all your bolts. Can't stress this enough
31 Now grease all the pins and pass through holes with a good grease. I put both shoes on and let them hang like this. If you are messy, it is a good idea to put wide masking tape over the shoes surface.
32 You need to make sure the pistons in the wheel cylinder are lined up correctly. there are slots on most of them that need to be straight, up and down. Align the rubber boots the same. Now we are ready to install the spring.
33 I straddle the axle and hold the shoes in place with my knees as shown.
34 Then use the tool to slip the spring in.
35 Now you want to turn the adjustments so the shoes are in as far as possible. Makes getting the drum on easier. they are normally wore enough that it doesn't matter but it is a good practice to do.
36 With everything on I then spray the shoes with brake clean and wipe off. You don't want any oil or debris on them. Wipe the inside of the drum surface down as well after you knock any loose stuff off.Clean the surface on the axle hub and drum where the meet up too.
37 When I install the drum, I lightly cover the mating surface with antisieze. I then reinstall the 3 slot screws. Don't over torque them as there is no need. Just nice and snug. Take the view hole cover off if you haven't already. You want to adjust the top cams first. Turn one till you see it close. Then keep turning the drum till you feel it start to drag. You don't want it so tight that you can't turn it let it still be able to move. I think the book says .003- .007 clearance but you just want them as close as possible and even. It'll give you better brakes and a quicker pedal. Some use a feeler gauge in there but I choose not to.
38 Hard to show but you can see it come closer as you turn if you shine a light in there. After getting both the tops, move to the bottom. The extremes on the adjustment cams are when the flats are straight up and down. Spin them and watch the shoes move out to the drum. Same thing as before, Close as you can with some more drag.
39 With that, you should be ready for the next one.
