Trailer (air) Brakes Reline- Inboard Drum- Part 1
Trailer (air) Brakes Reline- Inboard Drum- Part 2
There is two types of brake drums today we are talking about the inboard style
Inboard style drum- the type you need to take the hub off to access the brakes
Outboard style drum- the newer type that you can remove the wheels then remove the drums and access the brake shoes without disturbing the hub
There is times when you might want to follow this procedure even for outboard style drums- when the wheel seal is leaking or when you would like to check and repack the wheel bearings
The example I'm using is a trailer with BPW axles
Jack your wheel up, make sure you jack in an appropriate place where its not going to damage anything.
Make sure your brakes are released. Build up your air, chock the wheels, release the brakes.
Then Back off your brakes so the drum will slide off easily and not get caught on the lip
Remove your hub cap
Remove split pin- get the back section as straight as possible
Undo the nut, this one only has one nut because we have the split pin locking it. Others have two nuts with a locking washer that is bent over to lock it in place
A trick that I use when I'm not on concrete and I don't have a wheel dolly. Get a flat piece of tin put some oil on it so the wheel will slide. Then let the jack down a little bit so the weight of the wheel is on the tin but not too much that you start getting the weight of the axle
Slide the wheel off. Sometimes you need to get in behind it and give it a push to get it started
Wheel is off
Take brake shoes off- take springs off, use a screwdriver to get in behind them and flick 'em off
There is springs on the inside and outside
Mark the brake shoes before removing them especially if you are going to re use them. With new brake shoes sometimes you will see written on the box- radial ground and the shoes have a sticker saying this way facing out.
Brake shoes off, check the s-cam play. A general max movement spec is .75mm or 3 thou
Slide the inner bearing off the stub axle
This particular set up has a different seal than most. It uses two plastic/ nylon discs. One part of the disc pushes hard up against the inside of the hub, the other side pushes against the stub axle
When inspecting the drums you are looking for grooves and excessive cracks. There is a special tool to measure the diameter of the drum. You take this measurement against the manufacturers specifications or sometimes it is written on the drum itself. Generally if you can feel a lip- replace the drum
To remove the drum, undo the row of nuts then jar with a hammer and lift it off
Technically your are not supposed to hit the drum. I'm replacing these anyway so it doesn't matter
Clean out the hub, I like to use disposable gloves for this part of the job. Once you have the majority of the grease out of the hub get some newspaper or old rag and give it a wipe out
Ideally if you had a pressure washer/ steam cleaner you could use that
Clean the bearings by spinning them in kerosene, this gradually gets the grease out of them. Use an air blower to lightly blow the grease and kero out
Repeat the process with clean kero until the bearings are clean
Take your bearing into the light and look down into the inner cone. If you can see pitting or damage to the hard facing on the inner race or the rollers the bearings need to be replaced
Check the bearing cone in the hub for pitting or damage. Also grab hold of the cone and make sure you can't spin it in the hub
Fill the hub with grease, fill the valley level with the cones
Pack bearings with grease.
Take the new brake shoes and fit the hardware kit- Fit the rollers and fit the springs
Set your s-cam so it is horizontal- flat, this makes it easier to fit the brake shoes
Fit the brake shoes, fit the springs
Fit the brake drum- sit the wheel/ hub on a 45 degree angle. This makes it easier when sitting the brake drum on, it will now sit on the lip without falling off
Clean the brake drum with brake cleaner- the brake drums come with an oily residue on them to stop rusting
Brakes work on friction- oil and grease on the drum or linings will make your brakes not work properly. Be careful with brake linings as they absorb oil and grease and you cant get it back out. That includes dirty greasy fingerprints
Wipe where the seal is going to go
Fit new seals
Put bearing on stub axle
Put the flat piece of tin down with a small amount of oil on it.
Adjust the height of the stub axle. Make sure the brake shoes are contracted (s-cam flat)
Push the wheel on, fit outside bearing, fit nut
Try to get the hub on as far as you can before jacking up the wheel. Having the outside bearing and nut firm lets the bearings take the weight of the hub and doesnt put pressure on your seals. This is especially important for the other type of seal
Jack your wheel up off the ground
Tighten your bearing up almost as tight as you can get it turning the wheel as you do it. Then get a sledge hammer and hit the top and bottom of the tyre to jar it to make sure it is all the way home
Once you have it tight and all the "way home" Back the nut off 1/2 to a 1/4 of a turn. Then by holding just the socket do it up as tight as you can by hand. Put the bar back on and tighten it a little bit more.
Check your wheel bearing play. What your aiming for is to just take the play out of it. Hopefully the split pin hole lines up if not you will have to back it off to the nearest hole.
Check the wheel bearing play with a dial guage
Fit split pin, bend the split pin over
Fit the hub cap
Packing Bearings By Hand
Bearing Packer Tool
Note- You will need a bigger bearing packer for truck bearings
If you want a long, indepth, by the book, how to this is the perfect playlist for you. From Fanshaw Motive College.
If you want a video on brake reline- outboard drums