Broken Rear ST1100 Wheel Bearing

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So the wife and I decided to go to ArkanSTOC and prior to leaving I made the decision to replace both tires and the rear wheel bearings when I got back. So I ordered what I needed and a bearing removal tool. So yesterday I got the wheel off and decided to replace the bearings on the rear before I mounted the tire.

The drive side came out fine but the left side (rotor side) did not. Everything seemed fine but when I gave the bearing tool a whack to pop the bearing out the bearing came out in pieces. The inner race shattered, the bearing cage was in tacked. This left the outer bearing race in the hub. Oh crap not a good thing. After a cup of coffee I got the dremel tool out with a small cut off wheel and cut a slot in the race and finally got it out.

The bearing did not seem like it was bad but I have nearly 70k on the bike an thought it might be a good time since everything was a part. After a night of thinking if the bearing was bad or did I break the bearing with the removal tool. Seems unlikely but one never knows. So I dug the drive side bearing out of the trash and tried to fracture the inner race with the removal tool. Nope that is not happening.

So has this happened to anyone else and if so was the bearing bad or did the tool break the race?
 

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BakerBoy

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No, I've not seen that in a motorcycle bearing, but it has the makings of fatigue. Without seeing the inner race at its failure surface, i'll speculate that the inner race had almost failed, already,
 
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Honestly I was rather surprised when it came out in pieces. There is no metal discoloration. The grease is a little brown, but not what I would say is burn. The axle shaft looks good.

The bearing did spin and seemed smooth prior to putting the tool in the bearing.
 

STraymond

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Honestly I was rather surprised when it came out in pieces. There is no metal discoloration. The grease is a little brown, but not what I would say is burn. The axle shaft looks good.

The bearing did spin and seemed smooth prior to putting the tool in the bearing.


To quote Bullwinkle T Moose: "I guess I don't know my own strength!".....
 
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John, it is already in the bike. It will be interesting to see what thoughts there are about this.
 
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this would be a great question for a metallurgist at a bearing design company, and if you provide the pieces to the company that made it - they may actually do a failure analysis on it and gain real insight - for the engineer it is valuable data/insight. Could be a grain boundary enbrittlement and when you whacked it the ball bearings cause a radial crushing force "she can't take it Captain" and it fractures.

I'm not sure that the bearing races fail from cycle fatigue before the balls and inner race surface become exceedingly rough - i think that is the norm rather than micro crack propagation through the races as a result of cycle fatigue - but i'm only guessing at this point rather than data.
 
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Your 25 yr old bearing was destroyed by tool and/or technique used for removal. The bearing cone which disintegrated is designed to run on a shaft that is inserted easily, by forcing it outward with pry bars or hammering on the tool to expand it would naturally shatter, nothing new or mysterious.
 
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BakerBoy

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Brad brought the bearing remnants to our RTE today and I looked at it ... there's no galling, no heat discoloration of any metal, the grease was well aged but hadn't coked, and the inner race showed sudden fractures at odd angles. The shattering happened in one sudden failure, definitely, as illustrated by the fracture faces (I'm not a metallurgist, but I have some working for me, so I see component fracture faces often).

It looks like the failure is most likely due to the impact loading from the puller, possibly amplified by the bearing being a bit worn so that the balls pressured the inner race oddly when it was 'whacked' in a direction that the bearing is not normally loaded. It did appear a that the inner race may have had some fatigue at the edge of the race (there were slightly different oriented & textured facets there), but that was not for certain as those features were small, I was looking by eye.

No metallurgists were harmed in the above inexpert analysis. :D
 
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John

Thanks for the analysis this morning. I have another set of front and rear bearings to do in about 9000 miles on my wife ST1100. Hopefully this bearing extraction will go smoother.
 

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The bearing did not seem like it was bad...
Yeah, since when?
I mean when was the last time/how much miles since you actually checked the conditions of the wheel bearings?
Was the grease in the axle seal/spacer collar replenished frequently? (or is this area even hit with the pressure wash?)

The bearing shown looks heavily corroded, rust... so water was leaking into there through the axle seal, washing out the grease, etc...

I check the wheel bearings on any occasion the wheels come out... at latest during changing the tires (so at least every 12Tkm/7500miles)
Poke the index finger in, rotate the inner race, if that rotates rumbling, wiggling or anything else then smooth, them bearings get binned.
Axle seals get packed with marine grease, and the spacers/collars carefully cleaned before reinstalling.

And every time the bike is on the platform, wheels elevated (like replacing brake pads, during the annual MOT, etc...) the wheels get rotated and wiggled by hand...
 
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The bearing shown looks heavily corroded, rust... so water was leaking into there through the axle seal, washing out the grease, etc...
Bearing was clean not corroded or rusted. The grease is just dark.


check the wheel bearings on any occasion the wheels come out... at latest during changing the tires (so at least every 12Tkm/7500miles)
Poke the index finger in, rotate the inner race, if that rotates rumbling, wiggling or anything else then smooth, them bearings get binned.
I to check the bearings every time the wheel is out. That is standard process.

If the bearing turns freely without being notchey and does not have side play it is assumed to be good. But miles will also play into that as well.


(or is this area even hit with the pressure wash?)
Never ever pressure wash your bike, especially around wheels and tires. The high pressure water will get into everything. High pressure washers are a major cause of corrosion on the wheel where the bead of the tire seats. This is especially bad for tubeless rims.
 

ST1100Y

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Bearing was clean not corroded or rusted. The grease is just dark.
Wasn't clear on the pic...

I to check the bearings every time the wheel is out. That is standard process.
If the bearing turns freely without being notchey and does not have side play it is assumed to be good.
Astonishing and quite unusual that a bearing just "explodes" like this...

I normally see such only on servere neglected bikes in the workshop... being parked outside year round and such...

Never ever pressure wash your bike, especially around wheels and tires. The high pressure water will get into everything. High pressure washers are a major cause of corrosion on the wheel where the bead of the tire seats. This is especially bad for tubeless rims.
Bad anywhere on a technical apparatus... ;-)
 
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I think there are some lessons learned here:

Don't be in a hurry. Plan your maintenance well in advance of a ride.
Have your replacement parts in hand. (Ordering parts takes time when you are in a hurry.)
Things are salvageable if you think and take your time.
Even with proper tools sometime things just don't go right.
Although there are differing opinions on forums, there is valuable information that can be used to solve issues.
 
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Just as a follow up, I did another set of wheel bearings on my 2000 ST. One bearing came out fine, but the tool I am using came out of the bearing several times before the actual bearing moved and popped out. I did put some heat on the hub and I did clean all the grease from the ID of the inner race and the OD of the tool. The second bearing however did not move.

The tool is one of those where it is pushed into the bearing race from the outside and a tapered rod is pounded in a slot of the tool through the center of the wheel. After several times of trying to get the tool to stay in the bearing I gave up and just used a punch to knock the bearing out.



And to my amazement the inner bearing race was split. Very similar to the last bearing the we looked at. The tool fits snuggly in to the bearing race and it takes several hard hits with a hammer to seat the tool so it does not move. I did notice that when the tool was seated with the tapered rod that the inner race would no longer spin. I am thinking that the tool is actually expanding enough when the rod is seated to expand and crack the inner race.

So one of two conclusions:
1. the tool does not function as expected and requires to much force on the taper to hold in position or;
2. I am using the tool improperly.
 

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I have had three left-side bearings give up over the years, in addition to several bearing changes where the left side indicated bad without falling apart. Never had the inner race come out in pieces tho the outer race has had to be cut out all three times.

I never leave home without a set of front and rear bearings in the kit, 2 or those three failures plus one none-fail change have occurred on the road. I anticipate a change at 50,000 miles tho I have gone farther. Ron Majors used to change his at 25,000 miles, no matter what.

Glad ya got yurs fixed.
 
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So one of two conclusions:
1. the tool does not function as expected and requires to much force on the taper to hold in position or;
2. I am using the tool improperly.
+1 on #1 above. If you want to remove a bearing in one piece, only force should be applied to the outer race. IMHO, don't expect an old bearing to come out in one piece using that tool. And BTW, I have never seen a tool such as that. Just curious : How long have you had it, and where did you get it from ??
 
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I got this tool off Ebay. It wasn't a lot of money, I think $40 but I bought it to do my rear wheel bearings. The fronts can be done with a good flat end punch and you are able to get to the outer race and knock it out from the opposite side. The rears are different. There is no access to the outer race. The tool that I have shown strongly resembles the bearing removal tool in my maintenance and repair manual.

If there is a different tool out there please show me what it is, because I am not thrilled with this one. It shouldn't be this difficult to knock out bearings with a good tool.
 

ST1100Y

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If you want to remove a bearing in one piece, only force should be applied to the outer race.
Agree...
I only know the expandable ones as shown here:
trannyset.jpg

or the kits with a slide hammer:
blind_bearing_puller_900.jpg

On ST wheel bearing I simply use a steel rod...
Lever the spacer tube aside, poke in with a flash-light to locate the gap in the bearing seat, place the rod there, two short strokes with the hammer, set the rod at the other side, etc...
Removing a bearing will always bring side load on the balls, thus the bearing is shot anyway...

Installation is a different issue, always clean the seats thoroughly, apply a slight smear of marine grease to ease the installation, use a tube of proper diameter (or simply the outer race of the old bearing) to seat them in the rim, never forget the spacer-tube(!!!) before installing the narrow, LHS bearing though.
And then there is one minor exception:
once the second bearing is installed, its most likely that the inner races will jam on the spacer tube... and since ball bearings don't like side loads, not a good situation.
Therefore is this the only occasion I'll actually tap on an inner race, place a tube of proper diameter on and give it a gentle knock with the handle of a screwdriver (or a very tiny hammer, piece of a 2x4, etc...), flip the wheel over and do so on the other side as well, always checking if then both races + spacer tube rotate freely... and it'll only take 2~3 gentle taps to achieve that...

(I'd learned that many years ago while fixing electric motors (washers, diswashers, fan motors air handling units, HVAC...), new bearings will always slightly jam once the covers are back on the stator, the side load is causing a distinctive noise/howl upon powering up, so I always used a mechanic's stethoscope and a small plastic hammer, gentle tapping covers and shafts to remove all the stress and tension from the new bearings during the workbench test-run... the bearings in those motors then lasted forever...)
 
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