How do I replace bearings in a jackshaft?

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remush
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Hi all,
I need advice in how to replace bearings in a jackshaft housing.

The housing is about 9cm long, and is made out of Aluminium.
It has cups at each end with bearings currently fitted that need replacing.
There is a hardened solid steel shaft running through the inside of the bearings, that protrudes about 4 to 5 cm each side.

the shaft is 15mm thick.
Here's an example of something similar, except my jackshaft is just a cylinder.
example

The bearings are ID 15mm OD 28mm 7cm wide.

The shaft to bearings is a press fit, or what is sometimes called a interference fit.

I have no special tools at home to do the job. The jackshaft is a part of a mid drive electric bicycle kit, mounted on a bicycle I use as a food courier. I've found a few workshops that will take on the job but the wait time is 1 to 2 weeks, time that I wont be earning money.

Advice and suggestions welcomed and appreciated
Thank You
 
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Welcome to PF.

The bearings are probably deep groove ball bearings.
Can you read the part number and suffix?
ID 15mm, OD 28mm, 7cm wide, is probably a commodity part number 6902.
The suffix will identify the seals, probably 6902-RR or 6902-2R meaning rubber lip seals.
They will be really cheap from any bearing supplier.

To dismantle the unit, first check for and remove spring retaining clips. See if you can find a lawn mower, bike or car mechanic workshop with a small press you can use. You will have to put the assembly in some sort of press, that will push the shaft out with one bearing. Then push that bearing from the shaft, and the other from the housing.

Assembly is the opposite sequence, but you must press only on the bearing rings that are a tight fit, so you do not bruise the bearings.

If you do the job with a hammer and old water pipes, and it goes wrong, you will have to buy more bearings. Take care not to dent the shaft or fracture the aluminium casing. If the bearings are a tight fit in the casing, warm it all up so the aluminium expands and the fit is easier.

Search YouTube for a video.
 
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FAQ: How do I replace bearings in a jackshaft?

What tools do I need to replace bearings in a jackshaft?

To replace bearings in a jackshaft, you will typically need a set of wrenches, a bearing puller, a mallet or hammer, a socket set, a torque wrench, and some lubricant. Depending on the specific setup, you might also need a snap ring plier and a press for installing the new bearings.

How do I safely remove the old bearings from the jackshaft?

First, ensure the machine is turned off and disconnected from any power source. Use the bearing puller to carefully remove the old bearings from the jackshaft. If the bearings are particularly tight, you may need to use a mallet to gently tap them out. Be cautious to avoid damaging the jackshaft or surrounding components.

How can I identify the correct replacement bearings for my jackshaft?

Check the part number on the old bearings, which is usually stamped on the side. If the part number is not readable, refer to the machine's manual or contact the manufacturer with the model number of your equipment. You can also measure the inner and outer diameter and the width of the bearing to find a compatible replacement.

What is the proper way to install new bearings on a jackshaft?

Clean the jackshaft and the bearing housing thoroughly before installation. Apply a small amount of lubricant to the shaft and the inner race of the bearing. Press the new bearings onto the jackshaft using a bearing press or gently tap them into place with a mallet, ensuring they are seated evenly. If your setup uses snap rings, make sure they are securely in place.

How do I ensure the bearings are properly aligned and secured?

After installing the new bearings, rotate the jackshaft by hand to check for smooth operation and ensure there is no binding or misalignment. Use a torque wrench to tighten any bolts or fasteners to the manufacturer's specified torque settings. Double-check that all components are properly secured and reassemble any parts that were removed during the process.

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