Refitting wheel bearings, advice please?

[car]

The Haynes Book of Lies for my ZXR750H2 says that the front wheel bearings should be drifted in "until the recess for the snap-ring is visible", after which the snap-rings should be fitted. Job done.

Except...

I had a pig of a job getting the old bearings out because the bearings were drifted in far enough that the spacer between them couldn't be moved more than 1mm or so -- I just couldn't get a drift in to the inside, not even to the inner race. In the end, I had to disassemble one bearing on each wheel (pull the seal, destroy the cage, pull each ball-bearing out of the races) so that I could get a drift in to knock the bearing on the other side out.

With the new bearings in (exactly the right ones, same as the old ones) far enough to fit the snap-rings, there's now about 3mm of space between the inner face of the inner race and the spacer -- I can rattle the spacer about, and I'll have no trouble getting a drift in to knock this set out, should I have to.

Question is -- should I knock the bearings in further than they need to be to get the snap-rings fitted? Should they be flush up against the spacer?

My first reaction is that the snap-ring is the guide -- if they're in that far, they're in far enough, and more importantly they're in the same distance on both sides.

But I'm open to more learned opinions.

Cheers,

Chris.

[Ocean1]

The job of the spacer is to spread the compression load when the axle nut is tightened, so that there's no axial load between the bearing inner and outer. Not familliar with the bike but usually there's a register against which the bearing outer should be pressed, when bothe bearings are in the spacer should be lightly loaded. It's possible the spacer has been either crushed or worn by a seized bearing, in which case it needs replacing. It's also possible the bike's got an entirely different set-up than most, possibly a spacer missing?

[car]

The job of the spacer is to spread the compression load when the axle nut is tightened, so that there's no axial load between the bearing inner and outer.

Hmm. That makes sense.

Not familliar with the bike but usually there's a register against which the bearing outer should be pressed, when bothe bearings are in the spacer should be lightly loaded.

On one side, you could (were it not for the spacer) drift the bearing straight into the void in the centre of the wheel. On the other side, there's a lip that you could seat the outer race on.

Sounds like I've got some more hammerin' to do...

[Ocean1]

SOrta makes sense, only need one outer to be retained. Don't pound on the inner though eh? Nice dolly a mm or so smaller than the outer is good, socket at a pinch...

[Coldrider]

I recently replaced the front bearings on my ZX9R, there was a snap ring on one side only. With the snap ring on the bearing fits between the snap ring & the backing perfect. The bearing on the other side is pressed in till the spacer takes up, provided your spacer is the correct length, the bearing should not pass any futher than the outer hub housing.
you could measure where this should sit and make a new spacer if it is incorrect, make sure it is cut very square.

[Ocean1]

I recently replaced the front bearings on my ZX9R, there was a snap ring on one side only. With the snap ring on the bearing fits between the snap ring & the backing perfect. The bearing on the other side is pressed in till the spacer takes up, provided your spacer is the correct length, the bearing should not pass any futher than the outer hub housing.
you could measure where this should sit and make a new spacer if it is incorrect, make sure it is cut very square.

If it comes to that PM me and I'll machine one.

[car]

If it comes to that PM me and I'll machine one.

Thanks. I'll bear that in mind for future reference...

I've got the front bearings fitted and the wheel mounted, without a tyre currently. All goes together nicely, apart from the speedo drive which I noticed was a bit bent up when I took out, so dutifully straightened out. Now I can't get the bugger to sit in its little recess without binding on the outer of the snap-ring. Bah, it'll bend, or I'll take the angle grinder to it. With the previous owner's record, there's every chance that this is the wrong speedo drive.

I knocked the RHS bearing into its seat with a socket that was only slightly smaller than the outer race (not small enough that it clipped the seal on the bearing) then tapped the LHS bearing in just until I felt it take the slack out of the spacer. It all turns nicely by hand, but the spacer isn't rattling around at all. Just how I remember it, apart from there bearings don't rumble. Pity the poor sod who needs to get them out!

Now for the rear, and then to a tyre fitter to get some rubber back on 'em. By the time this wind dies down -- November, I'm guessing -- I'll be able to get her out on the road. Woohoo!

[vagrant]

I have a bearing puller designed just for this sort of job. You drill thru the bearing cage, and the puller arms have a flattened ball that slides between the races and twists to lock. Turn the handle and the bearings slide out.
Got it for doing the bearings on the VFR ages ago.

As an aside, did you check the new bearings are packed with grease??

The ones I got for my VFR had a thin squirt of a light preserving grease on them. They would not have lasted long running like that
I only found that by accident, one of the seals was not installed properly.
The engineering shop where I got them was not aware the factory had not put a proper grease in them either.
They did a check and found loads like that. SKC was the brand.
Wasn't very impressed with them putting people and vehicles at risk like that.

[car]

As an aside, did you check the new bearings are packed with grease?

No, I didn't. They're sealed both sides and I assumed, as you do, that they'd be packed with decent bearing grease. I figured that doing as little as possible to risk damaging the seals was my best course of action.

[Coldrider]

With the bearings in the wheel you should still be able to pop the bearing covers off, they are probably made of plastic, ease the outside facing ones with a very small screwdiver, they should pop out if prised from the centre, without damage, then smear in some grease if there doen't appear to be enough, do not overpack with grease or the bearings will overheat.
The bearings i had were NTN I think and there was plenty of grease in them.

[Ocean1]

No, I didn't. They're sealed both sides and I assumed, as you do, that they'd be packed with decent bearing grease. I figured that doing as little as possible to risk damaging the seals was my best course of action.

They're not nescessarily being stingy, they supply the bearings with the correct quantity of grease for the bearing's maximum rated speed duty, too much and a bearing can overheat. Wheel bearing duty is very low duty in terms of both load and speed (rpm), so in order to improve (slightly) lubrication and , (more importantly) better exclude moisture and grit you can carefully pick the seal out of one side, wash out the existing grease and re-load the bearing with fresh stuff. For low speed duty they reckon fill about 60% of the bearing cavity, so push grease through the balls and cage and then wipe most of it out of the open side with your finger. Push the seal back in with your finger and continue as normal.