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Ep 10: Replacing rear wheel bearings

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Started 6 months ago by Waz
Latest reply from Ogri Grindstaff

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Waz
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Garage Night TV has turned 10! Well, it’s our 10th episode, anyway. In this instalment, Pete replaces the rear wheel bearings on his Honda Africa Twin 750 - and gets a nasty shock when he finds what some previous mechanic has done in this department.

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Sealed bearings. Great! They come from the factory with lots of lovely grease inside, and their own integral seals to make sure the grease stays in, and the muck stays out.

Right? WRONG! For me, the biggest revelation of this episode came when Trent popped open one of Pete’s new bearings and showed that inside was little more than a token smear of factory lubricant. So if you really care about those bearings lasting, it’s a good idea to check them - how to go about this is one of the numerous tips you’ll get by watching the video.

If there’s a lack of grease, you might consider adding some yourself. It’s not recommended to pack them solid, though, due to the possibility of overheating or hydraulic lock. There’s a bit of debate on this, but about 1/3 full of grease is one recommended figure.
Ep 10: Replacing rear wheel bearings
Posted 6 months ago #
guest
Inactive
Very informative. You might consider using a heat gun to expand the hub a bit before removing or installing a bearing. In addition, you can store your new bearing in the freezer, to cool it down, as well. Just a **little** bit of thermal expansion can make a big difference when trying to remove or install a bearing. I suspect that more bearings get damaged by folks removing the seals to add more greaase. They damage the seal, and potentially introduce contaminents and debris into the bearing. If you absolutely **have** to do it, perhaps it might be better to only remove the inner seal (the one inside, that faces the other bearing) since (perhaps) no dirt can get to the back side of the bearing.
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Author: Brian Mehosky
Posted 6 months ago #
Waz
Key Master

Brian, nice to hear your opinions - I believe you may have some connection to the bearing trade? That’s a top tip about facing the disturbed seal inwards. Very sensible precaution.

Posted 6 months ago #
guest
Inactive
Great video. Rear bearings on my Transalp are fkded, something I suspected after noticing riding on grooved tarmac where the whole back end felt like it was floating. Gonna extract the old ones and hot foot it down to my local bearing shop to match up some fresh ones. Thanks again, I have the shop manual but talk of special tools can be a bit off putting………..
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Author: Mike Pinney
Posted 5 months ago #
Waz
Key Master

Hi Mike, we are always happy to save a Transalp owner a few bob. Our stickers look particularly fetching on v-twin Hondas, by the way …

Posted 5 months ago #
guest
Inactive
Hello guys, I’m new to tooling and instinctively shy away from having a go. However for the first time I fitted new front wheel bearings. My concern is that I might have driven the bearings in too tightly to the inner spacer causing the inner diameter of the bearings to hardly turn without some force from my finger. Should the bearing inners spin freely without too much finger pressure to get them to turn?

Great website and video tutorials by the way!
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Author: PaulH
Posted 4 months ago #
Waz
Key Master

Hi PaulH. Well, when you try to rotate one bearing inner, the spacer should spin with it, as well the bearing inner on the other side. So you might get more resistance than you’d expect if you were just holding one bearing in your hand and spinning it. They should not spin loosely or freewheel - that would be a sign they’re really worn. But they should not be severely tight either.

Just make sure you didn’t a) drive against the inner bearing diameter when installing them, thereby causing damage, or b) over-pack the bearing with grease (no more than 1/3 full is one recommendation) c) badly misalign the inner spacer so it’s rubbing on the bearing seal (you can push the axle through to help line things up).

I’d suggest installing your wheel on the bike with the weight off it and the brakes out of the way so they’re not dragging on the disc. Then see how freely the wheel spins.

It shouldn’t really be possible to ‘over-drive’ the bearing so that it jams because of the spacer - the spacer will be the right width so that it’s held in place by the bearing inners when the bearings are seated in the hub.

Hope that helps. If you’re really unsure about it or feel it might not be safe then do see a mechanic about it.

Posted 4 months ago #
guest
Inactive
Hi Paul,
Waz’s suggestion to refit the wheel to the bike (tighten the axle) and give it a spin (without the brake callipers attached) is a sound idea.
If the wheel spins freely for a number of revolutions (5 +) then I suspect everything is OK.
If it stops after 1/2 - 1 revolution, then something is wrong.

The only bike I’ve heard of with front wheel bearing spacer problems is the KTM 950 Super Enduro - the spacer on some of those bikes is too short which causes the bearings to be bind up when the axle is tightened - Spinning the wheel as described above is the way to detect that problem.

It can be a bit daunting working on your bike for the first time, but keep focused, use the right tool for the job and you can’t go too far wrong.
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Author: trent
Posted 4 months ago #
guest
Inactive
Thanks guys, my bike is an Yamaha RD500 so a little different from the bikes you seem to work on. Bearings were driven in with large socket on the outer edge of the bearing only, although I did have to knock out one bearing and refit which I did by knocking on the inner edge with a drift. The bearing looked ok to me upon inspection so I reused it. I am unable to fit wheel to bike at the moment because my forks are stripped waiting for rebuild. I will do as suggested, fit wheel and spin and see how it goes. I have to get the tyre refitted cause the tyre company has fitted tire wrong way round. During this they should be able to spin the wheel on their balancing machine to indicate if bearings are too tight? If so I could get that done this week.
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Author: PaulH
Posted 4 months ago #
guest
Inactive
Hello guys. I have just built my forks and have been able to assemble front wheel onto the bike today. The wheel just on the axle alone is tight but even tighter with the caliper fitted. I thinks this is too tight but I’m hoping this will bed in. Here’s a youtube vid I made to demonstraight.

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Author: PaulH
Posted 3 months ago #
guest
Inactive
Just realised you wanted me to spin wheel with caliper removed. It does spin better but still tight. I think this is probably ok but would appreciate any feedback.

Cheers. Paul

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Author: PaulH
Posted 3 months ago #
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Hi Paul,

Hmmm… That seems way too tight to me - Did you remove both calipers? It sounds like you still have something rubbing when you spin the wheel (sounds like a disc rubbing on brake pads)

With new bearings and no calipers, I would expect the wheel to spin freely with just a small amount of force.

Is the video taken with the axle done up tight? If so, loosen it and try spinning the wheel again - there could be a problem with one of the spacers that’s causing the bearings to bind up when you tighten the axle.

Do you know if the wheel spun freely before you changed the bearings / repaired the forks etc? I’m trying to figure out if it’s something you’ve done or if there was a problem all along that you’ve discovered.
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Author: trent
Posted 3 months ago #
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Inactive
Hello,

I don’t know what the wheel spun like before, never really tested. I bought second hand wheels and reused the spacers and other parts from original wheels and just added new wheel bearings and seals. I did not repack the bearings with more grease, I just left them as was. I followed your video’s demonstration and knocked bearings in with the right size socket and both went in straight. However, I did have to knock the first wheel bearing back out again before second bearing was fitted because I fitted the parts wrong way round first time. This meant having to use a drift to knock the bearing out on from it’s inner. I had a good look at the bearing for any signs of damage and it all looked ok and spun freely in my finger so I reused it again. I refitted with the correct parts in the right order and everything lined up straight as far as I could tell. My only concern was that the bearings may have been knocked in too hard and pressed too tight against the spacer? I then completed putting everything together for you to see via the youtube videos.

The second video was without the calipers fitted and axle torqued up correctly. The first video wasn’t. I have posted this concern on the RD website and the feedback I got from one at least is that it looked ok for new bearings and seals fitted and should hopefully wear in. As I have no experience of this I don’t know what is true. What I do know is that my BMW GS1200 front wheel is alittle tight also so other than that I don’t really know?
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Author: PaulH
Posted 3 months ago #
Waz
Key Master

hi paul, i like trent’s suggestion to undo the axle and any pinch bolts and give it a spin.

is there a speedo drive that could be offering resistance?

if you take the wheel out, put the axle through, rest the axle ends on say two panniers and spin the wheel how does it look?

Posted 3 months ago #
guest
Inactive
Bit confused on adding grease to bearings now.

What is the perceived wisdom on leaving new bearings as they come from the factory, or as in the video packing them (or 1/3 packing them) with fresh grease?

Also if you have existing bearings that don’t appear to have a problem, is it a good idea to remove the seal and pack with fresh grease every few years? Or as above, is it best just to leave alone???
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Author: Rob
Posted 3 months ago #
Waz
Key Master

Hi Rob, you don’t have to add any if you don’t want, but Trent reckons it’s a good idea if the bearing seems to be under-greased. If the bearing is already about 30% full of grease I’d leave it.

Remove BOTH seals when checking because the grease might only have been injected on one side when it was assembled (it will be distributed when the bearing turns). If you only remove one seal it might look like the bearing is empty when it’s not.

I can’t see the harm in repacking an old bearings as long as you clean out the old grease first so you’re not over-packing it. Then make sure any solvent you’ve used to clean out the old grease is gone before putting the new grease in. I think WD-40 is good for cleaning old grease out because it will wash away the grease but is not a degreaser as such.

Posted 3 months ago #
guest
Inactive
Paul, is there a speedo drive unit on the axle somewhere? Are its tangs engaged properly in the wheel ?

If that’s all in order then I would take the wheel out of the forks, insert the axle. Hold each end of the axle and get a helper to spin the wheel. If it turns smoothly then you know the bearings and axle are okay. If it doesn’t then either one or both of the bearings may be pushed in too far or one might be defective. I was always told that knocking a bearing out by its ‘inner’ turns it into junk.
Did you put the wheel spacers back in the right sides? It’s usually only possible to put them in one way but have a look. Are you sure the wheel is all the way off the surface when you’re spinning it? I know, dumb question but it looks like it’s rubbing the deck. What the hell is that clicking sound? I strongly suspect a problem with the speedo drive unit.
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Author: Ogri Grindstaff
Posted 2 months ago #

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