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Mik

Trailer Disc Brakes & Wheel Bearings

7 posts in this topic

Ok, continuing from part 1

Removing the bearing tapered sleeve.

Get the pin punch on the very small step of the bottom edge of the sleeve. You can just see it in the pic. Tap the punch with a hammer alternating from top to bottom or side to side at 180 degree. Don't let the sleeve kick too much to one side or it will jam in the bore & cause scuff marks & damage to the bore, making fitting of a new sleeve difficult.

Just work away at it & it will come.

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Repeat the process at the other end to get the smaller outside sleeve out.

Now, after doing a thorough cleaning job on all the components with a suitable degreaser, you're ready to reinstall the new sleeves & bearings.

Keeping the sleeve square & up the correct way (The taper of the sleeve should be tapering outwards, or in other words, the thickest edge of the sleeve will be on the inside of the hub for both bearings) If you put it in back to front you won't have any step edge to put the pin punch against to try and get it out, then you might as well call my granny to give you a hand.

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In the diagram the grey shade represents the bearing tapered sleeve.

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Keep it square to the bore & gently tap it with the soft face hammer to get it started in the bore. Remember, this part above all else if extremely brittle & it will crack, snap or explode if you hit it on an angle to hard. Square blows with the hammer alternating around it to keep it square to the bore as it goes in. A good way to ensure things are square is to use a plate or in this case, the old brake pad to knock it in till its flush.

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You will notice that the sleeve isn't all the way down inside the bore yet.

I bet you threw the old sleeve in the bin didn't you! Go and get it speedy, you're gonna want to use it to knock the new sleeve all the way down to the shoulder at the bottom of the bore.

Sit the old sleeve on top of the new one facing the SAME way, IE Thick edge to the new sleeve & repeat the brake pad exercise until everything comes up solid. Now, the new sleeve is at the bottom & the old sleeve is in the bore on top of it.

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Repeat the process you used to removed the original old sleeve only this time just remove the old sleeve & leave the new on in place. Take care not to strike the new sleeve with the pin punch.

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Time for the gooey stuff. Pack the bearing with grease, trying to force the grease into the gap between each roller from the ends is the most effective way if you don't have a grease packer handy. Roll the bearing around a bit to spread the grease around inside.

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Apply some grease to the hub where the tapered sleeve is. About half full is good, don't go overboard with it. As the bearings wear in from new there will be a fair amount of heat (There is normally anyway during travel) The heat will expand the grease and if things are stuffed full in there you could blow the seals out.

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Time for the seal retaining / backing ring. (Steel ring)

Gently tap this in all the way so the outer ring edge is flush on top of the hub.

Now pop the new seal in & your in business.

Repeat these steps for the outside (Smaller bearing) except for the seal, its a different setup for that one.

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Now to remove the old brake pads.

Looking at the top of the calliper there are two cut outs in the housing, slide the outside pad to the cut outs & pull it upwards. Some callipers may have a different retaining method, but they should all be pretty easy to remove. There mat be springs to hold them in also. The springs on mine are not really required (New pads don't come with them anyway) The design of the pad (Shape) is what hold the pad in. The springs may help a little with pad rattle & thats about it. I didn't refit the springs in my setup.

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Once the first pad is out the second one comes out the same way. The inside pad should have a push plate also, which will probably fall out. Just try to ensure you note how it was sitting in the hole so you can put it back the same way with the new pads. There is a difference.

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Replacing the hub is straightforward. Two things to take care with.

Firstly, apply some grease to the axle shaft where the seal rides, this will help the seal slide on & hopefully stop any chance of it grabbing & damaging the seal.

Once everything is one, BEFORE you tighten the nut, double check from the inside that the seal is right up against the shoulder of the axle & that it looks ok. If anything is misaligned here you will have buggered bearings after the first boat outing.

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Now, you can leave the outside bearing until you have the hub fitted. Line up the hub & gently slide it onto the shaft. Take care & don't force it, you may damage the seal.

Once its hard up against the shoulder you can push in the outside bearing.

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Push the flat washer on now & then screw the nut on loosely. Give the hub a firm shake to ensure everything is in position. Tighten the nut with your fingers. Keep rotating the disc now & then to centre everything & ensure the hub is right back. Now you can tighten the nut.

Do the nut up firmly. Check that the disc still rotates freely & as the tension on the nut increases the hub will start to become firmer to rotate. If there are any horrible scraping sounds when you rotate the hub STOP, something is amiss & you should remove the hub to check things before any damage is done.

Now, several people have there own opinions on how you should tension the wheel bearings, here's mine.

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I like to do it up tight enough that the hub is hard to rotate but does still move alittle. Don't get all McGilla Gorrilla on it, just nice even pressure on the socket to apply the tension.

At this point I give the hub assembly a little love tap to make sure things are seated. Don't smack it like you would Bin Ladens Head, just tap it on the edge like in the picture as you turn the socket.

Tthe hub should still be tight to rotate but moving with some persuasion, now back the nut off about 1/8 of a turn to align the split pin hole up with the slots in the nut. Doing this should free the hub rotation up slightly but you don't want it so loose that it spins freely. If you grab it & try to spin it by flicking your hand, the hub should stop dead when your hand comes off. Trust me, the bearings will seat on first use & things should free up nicely until your ready to check & retension them after about 20-50 kilometres. As a side note, when the wheel & tyre are refitted, if you do the same spin excersise the added weight of the tyre should allow the wheel to actually spin. If you do this & it stops dead things are too tight & the nut should be backed off to the next split pin hole slot.

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Fit the split pin & bend it over fully on one side. You don't need to bend both legs of the pin unless they are so long that they foul on the grease cap. If they do foul, rather than bending both legs, trim the straight leg with a pair of side cutters. It makes getting it out again when the time comes much easier.

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Continued in Part 3..............

Edited by Boofhead

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looking good Mik :thumbup:

what grease are you using as it is a different colour to

the old grease used in the tear down pics

have you changed the grease used and was this because

of the grease properties ?

I ask as I don't like mixing grease in hub bearings and

I have seen hubs that were rainbow coloured from changing

the grease used when topping up bearing buddies

I was shown that the washer should be able to be moved

with a screwdriver blade after pre tension then pin to the

nearest hole location after checking the free spin

Chris

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Like I mentioned in the post, there are lots of methods for tensioning the bearings. As long as there is rotation by hand to some amount & nothing is making horrible grumbling noises you should be ok. The key is to check them regularly, Its pretty easy to do, jack her up & grab the wheel, if you can physically move the tyre from side to side & it feels loose then its time to add some tension to the nut again. If its grumbling then its probably time for a replacement of bearings.

As for the grease, because we buy in bulk for work & that EP lipex is on hand its what I use, we did have the red grease but changed brands due to a change in supplier accounts. Either way I can't see any sense in spending a fortune on wheel bearing grease, it should be changed regularly anyway. As long as the old grease is removed then its all good.

Some specalist greases react with each other & produce either heat or cause a breakdown of the greases rendering them useless as a lubrication. Mixing greneral purpose greases is generally not such an issue though, we're talking industrial and expensive types that start to get fussy on the mixing side of it.

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I thank you for your very good article and I did follow everything you said but I did not have a round punch so used a screw drive to hammer out the bearing selves and unfortunately marked the inner hub with small scratches you can see and fell with your fingers.

I think these will be a problem when try to put in the new sleeves. Do you have any advice on whether I should try to use something to smooth them out? Also when I took them out I notice they were not seated hard up against the shoulder and from what I can tell you suggest they need to be. Could you confirm if the the sleeves need to be hard up against the shoulder in the hub?

Thank you

George

Edited by Captgogo

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I thank you for your very good article and I did follow everything you said but I did not have a round punch so used a screw drive to hammer out the bearing selves and unfortunately marked the inner hub with small scratches you can see and fell with your fingers.

I think these will be a problem when try to put in the new sleeves. Do you have any advice on whether I should try to use something to smooth them out? Also when I took them out I notice they were not seated hard up against the shoulder and from what I can tell you suggest they need to be. Could you confirm if the the sleeves need to be hard up against the shoulder in the hub?

Thank you

George

Hi George,Boofhead wrote a great article to help others.In regards to your question,where you've mared the inner hub with the screwdriver use a file,emery paper,sand paper, to sand the ridge from the scratch down smooth with the hub so that when you fit the new bearing races they will not bind.A scatch on the inner hub won't be a huge problem it's the machined bearing race surfaces you want kept pristine.Also the races do need to be seated all the way down and flush with the shoulder in the hub.You can tell by the sound and the solid feel when they bottom out when hammering them in.

My tips-If you don't have a punch you can cut down a screwdriver and lightly sand the burrs with sandpaper for a makeshift punch that will have more surface area than a regular flatblade screwdriver which should help you from sliping and maring the surface as you have.

Another tip is borrowing(stealing)the wife's-daughters emery boards to do their nails they make handy little sanders for a whole host of things.

Cheers.

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I only wish I had found this info earlier, it would have saved me a lot of headaches and hours wasted. Now I see how the pad retainer springs fit in. This has to be the most informative and easy to follow article I have found after hours and hours of looking online. Can't thank you enough. 

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Thanks for a awesome article Mik.

On the bearing seal, I was advised by a knowledgeable person to avoid getting grease on the shaft where the seal sits as the rubber shouldn't spin on the shaft but inside the stainless cup. The seal should be packed with grease in the outer circumference. 

I may have it wrong but was told this is where most seals fail. 

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