A large share of bearings that fail early were damaged during installation. The rules are short, and following them costs nothing.
Before You Start
Check the shaft and housing for size, roundness and surface damage. Clean the seats. Have the correct tools ready, and leave the bearing in its packaging until the moment it goes on. Bearings do not need to be washed before fitting; the preservative is compatible with normal lubricants.
Force Path Is Everything
Mounting force must pass through the ring being fitted. When pressing onto a shaft, push on the inner ring. When pressing into a housing, push on the outer ring. Force passing through the rolling elements produces brinelling marks that are invisible at the time and become noise and vibration a few hundred hours later.
Cold Heat And Hydraulic Methods
- Cold — a fitting sleeve and a press or a soft mallet on the sleeve. Suitable for small bearings and light interference.
- Heat — an induction heater or an oil bath to 80 to 110 degrees Celsius above ambient. Never exceed roughly 120 degrees Celsius, and never use a flame.
- Hydraulic — oil injection on tapered seats and withdrawal sleeves for large bearings.
Step By Step
- Measure and record shaft and housing seat dimensions.
- Deburr and clean both seats, then apply a light oil film.
- Bring the bearing to the required temperature or prepare the fitting sleeve.
- Fit squarely, pushing only on the ring with the interference fit.
- Hold in position until a heated bearing has cooled and gripped.
- Check that the bearing is seated against the shoulder all the way round.
- Set clearance or preload where the design requires it, then fill with the specified lubricant.
- Turn by hand and listen before starting the machine.
Dismounting
Use a puller that grips the ring with the interference fit. Where a bearing will be reused, never pull through the rolling elements. Where it will be scrapped, it is still worth removing it intact so the damage pattern can be read.
