Wheel bearings are an important part of a tire's smooth operation. Not only tires, but also crankshafts, transmission shafts, and other parts of your motorcycle can be damaged by lack of lubrication, moisture, and foreign matter. When this happens, bearing replacement is necessary, and that's when a bearing puller comes in handy.
This article explains how to use a bearing puller without making any mistakes.
Turn the inner ring of the bearing and when you feel a rumbling sensation, it's a sign to replace it
Ball bearings are lined with steel balls between the inner and outer rings, each of which has a groove in it, to ensure smooth rotating motion. The ball bearings built into the wheel support the radial load transmitted from the tire, which is located at right angles to the axle shaft while rotating.
Bearings are not only built into tires but also into engines, and they are used in all kinds of machinery around us, not only in motorcycles and cars but also in home appliances.
The principle of using rollers to reduce resistance when moving heavy objects was already put to practical use in Mesopotamia in B.C., and the Industrial Revolution is said to have brought about the development of bearings.
With such a long history, proper lubrication is still essential for bearings in the 21st century. No matter how advanced materials and machining accuracy are, the parts that come into physical contact with each other must be lubricated with oil and grease.
In the case of wheel bearings, which cannot be lubricated with oil like the bearings inside an engine, the grease sealed between the inner and outer rings is the lifeline. Some bearings are equipped with rubber seals or metal shields to prevent grease leakage from inside and foreign objects from entering.
There are two types of rubber seals: the non-contact seal type with low frictional resistance and suitable for high-speed rotation, and the contact seal type with excellent dustproof and waterproof properties.
In the case of motorcycle wheels, many have a dust seal on the outside of the bearing to prevent water and dust from entering the wheel, so some older and out-of-print motorcycles in the 1970s were equipped with open bearings that did not have a seal. Older and out-of-print motorcycles of the 1970s had open bearings without a seal, and later bikes also have a single-sided seal with a seal on the outside of the hub and an open backside.
While there is an assumption that the bearings will not get dirty because of the dust seals, the reality is that the age of the seals can cause the bearings to become poorly lubricated from poor usage conditions. On off-road models that are often exposed to moisture and gravel, dirt can get into the sealed grease and damage the inner and outer rings.
Once damaged, it gets worse, but if the lubrication is inadequate, the inner and outer rings may seize up and stick together, or the retainer that determines the position of the steel ball may break, causing the rotating shaft to shift completely out of alignment.
To find out the condition of the bearings before they become such a terminal condition, check the rotation of the tire when it is floating and spinning. The load on the tire will be less than if you were to push it around normally, so it will be easier to tell the condition of the bearing.
If you remove the tire and turn the inner ring of the wheel bearing with your finger, you can more easily see the condition of the bearing because the inertial weight is removed. The same way you can check the steering stem bearing, it's easier to see its condition if you remove the tire or front fork.
If the inner ring is not smooth when you turn the inner ring with your finger and you feel a rumbling and stepping feeling, the bearing is likely to be defective and you can imagine that the condition will worsen further in the future, so it is safer to replace it with a new one.
- Point 1 - There are two types of bearings in the rotating part: sealed and unsealed.
- Point 2 - The condition of the wheel bearings can be easily checked by removing the tires.
Bearings are specified by inner ring, outer ring, and thickness.
The bearing that was installed was an open type without a seal, but the grease stayed in place because the oil seal was working (left). The 6304 bearing that we prepared for the replacement was nearly oilless and dry when it was new, so we had to apply grease to it before pressing it into the adapter.
The wheel bearing is pressed into the hub and cannot come off easily. If it comes off easily, the outer ring will rotate inside the hub and you will have a problem.
A special tool called a bearing puller is used to remove the press-fit bearing. There are two types of bearing pullers, the push-out type, and the pull-out type.
The push-pulling type inserts a chuck with a slit in the inner ring of the bearing and pushes the wedge into the bearing from the other side of the chuck to expand the chuck so that it is tightly sealed to the inner ring. You can use this chuck at the part where the shaft goes through, like a wheel bearing.
On the other hand, the pull-out type pulls the bearing out of the chuck by pulling it to the side where the chuck is inserted, and is useful for removing the bearing set in a blind hole.
About 25 years ago, bearing pullers were very expensive specialized tools, but today they are much more affordable than they were back then and are within the reach of many Sunday mechanics.
Although the bearing puller is like a typical example of a versatile specialized tool, the chuck included in the set often follows sizes around 8, 10, 12, 15, 17, 20, 22, 25, 30, 32, and 35 mm, regardless of the tool manufacturer.
If it's a spanner or socket, it's in 1mm increments, but why is the size of the bearing puller chuck skipped over? This is because the internal dimensions of bearings are set like this worldwide.
Ball bearings are called single-row deep groove ball bearings and are denoted with a four-digit number according to their outer diameter, inner diameter, and thickness. For example, the Kawasaki Z1/The Z2's front wheel has a bearing with the nominal number of 6203, the last two digits of which indicate the inside diameter, and 03, which has an inside diameter of 17mm.
Similarly, 00 has an inner diameter of 10mm, 01 is 12mm, 02 is 15mm, and 04 is 20mm. Since all bearings in the world follow this family of dimensions, the chuck size of the bearing puller is also available in these increments.
As an aside, if the ball bearings used in various parts of the bike, not just wheel bearings, have 4-digit numbers imprinted on them, you can get them as general-purpose mechanical parts, in addition to purchasing them as genuine parts for that model.
In the Kawasaki Z1/Z2 example above, if you know the factory part number of the front wheel bearing (601B6203), you can order it with this number, but you can also order it from a machine tool dealer or on the Internet, starting with the 4-digit number 6203, which is engraved on the outer ring of the bearing. However, it should be noted that this bearing uses C3, which has an internal clearance one rank wider than standard in the genuine part, so it may not be possible to determine the bearing by its four-digit nominal number alone.
Bearing pullers are available from several tool manufacturers and shops, but they all share the same basic action of crimping the inner ring of the bearing by expanding the chuck with a push bolt with a tapered tip. This product uses the gantry body as a stepping stone for pulling out bearings, but if the shape of the bearing holder doesn't allow the gantry to stand up, a sliding hammer can be attached to pull it out.
- Point 1 - Ball bearing size is indicated by a 4-digit nominal number.
- Point 2 - The general-purpose bearing puller can be used with various sizes of ball bearings.
Tighten the push bolts so that the chuck's claws do not come off the inner ring.
This is the basic style of bearing puller. The width of the legs on either side of the body can be adjusted to fit the bearing holder. The inner side of the chuck is tapered, and when a tapered push bolt is screwed into the chuck, the tip of the chuck expands and presses hard against the inner ring of the bearing.
A bit of a push bolt can be seen in the center of the chuck, which is grooved in the crosshairs. There is a slight flange at the end of the chuck, and it hooks onto the tapered part of the bearing inner ring. It is important to choose a reliable manufacturer's product because some have a good flange grip and some do not.
This is somewhat of a sidetrack, but you can use a bearing puller to pull out ball bearings that comply with ISO standards, regardless of the year and manufacturer.
Although the names of the parts vary from manufacturer to manufacturer, the bearing puller consists of a gate shaped body with adjustable width, a chuck that is inserted into the bearing, a push bolt with a tapered tip and a center bolt that pulls the bearing up.
The tip of the chuck, which is engraved with a cross groove, is slightly widened, and the push bolt is tightened once it penetrates the inner ring of the bearing. The inside of the inner ring of the wheel bearing is in close contact with the distance collar. However, the inner diameter of the inner ring is slightly tapered to allow the flange of the chuck to penetrate it.
If you feel a crack when you push the chuck into the inner ring, it is a sign that the shrunken flange has spread out at the taper. If the flange of the chuck tip is not caught on the inner ring, the chuck will come off the inner ring when the center bolt is pulled up, so it is important to tighten the push bolt firmly. Be careful not to tighten the push bolt when the flange does not penetrate the inner ring, as the chuck will slip. When the push bolt is tightened, the chuck will widen and press against the inner ring.
After the push bolts are tightened, put the gate body on the outside of the bearing outer ring for the first time and screw the center bolt into the push bolt. The nut and collar of the center bolt are tightened to the girder part of the body, and then the nut of the center bolt is tightened with a wrench.
The main advantage of the bearing puller is that it pulls the bearing up vertically, which means no damage to the bearing holder (in this case, the wheel hub) and makes the bearing replacement process a smarter one. It's one of the dedicated tools you'll want to have on hand when maintaining the undercarriage of your old motorcycle.
Insert the chuck that fits the inner diameter of the bearing, and tighten the push bolt when the flange is pushed to the back of the inner ring. Once the inner ring is flanged at the back of the inner ring, the chuck will not rotate any further, so it is important to tighten the bolt firmly.
Determine the width of the body so that the feet stand on the outside of the bearing, screw the center bolt into the push bolt to some extent, and then tighten the nut on the girder of the body while holding the hexagon of the chuck around with a wrench. When you pull hard on the bearing puller, you can hear a loud "clunk" sound at first, but then it comes out of the chuck with ease.
Because the flange of the chuck catches on the tapered part of the inner ring, the end of the chuck is in a tangle with the bearing. This allows it to catch on bearings set in a blind hole or even on bearings that are closely attached to the distance collar. Since the inner and outer rings are pulled strongly in the axial direction, bearings that are removed by the puller are not reused as a rule.
- Point 1 - The bearing puller is an essential tool for wheel bearing replacement
- Point 2 - The key is to hook the flange of the chuck tip on the inner ring of the bearing.
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