How To Install A Pillow Block Bearing
What is a Pillow Block Bearing?
A pillow block bearing is a type of mounted bearing that reduces friction and supports a rotating shaft. It comes inside a strong housing made of cast iron, ductile iron, or steel. These units are self-contained; they’re greased, sealed, and ready to install. You'll also hear them called housed bearing units. Pillow block bearings are usually bolted to a flat surface so the shaft runs parallel to the surface. There are two main housing types:- Solid housing: Single-piece design.
- Split housing: Two-piece design.
Inside the housing, you can find different bearing types, such as ball bearings, roller bearings, or tapered bearings.
To attach the shaft, you’ll use a locking device. Common options include set screws, eccentric locks, collars, or tapered adapters. Each has pros and cons. Seals also vary. Some seals allow clearance, others have light or heavy contact. Some pillow block bearings are fixed. Others are expansion versions that allow the shaft to grow and prevent loading against other bearings.
Choosing the shaft mount device and seal helps your bearing last longer. When installed correctly, pillow block bearings can run for years without replacement.
Step-by-Step Pillow Block Bearing Installation
Follow these steps to ensure minimal downtime and a longer service life. These guidelines apply to all bearing installs. However, this procedure is for the most common shaft locking device set screw or set collar, utilizing a fixed and expansion unit.
Tools list: Mallet, hardwood block, Allen wrench, torque wrench, washers (heavy washers or spring-lock washers), oil, scouring pads.
1. Check and Clean the Shaft
Make sure the shaft is clean, straight, and the correct size. Remove rust with fine sandpaper or a Scotch-Brite pad. Wipe away debris and apply a light coat of oil.
2. Position the Bearings
Slide the bearing onto the shaft. If you need to tap it into place, use a mallet and a hardwood block (or soft steel tube) against the inner ring. DO NOT strike or exert pressure on the housing or seals.
3. Lightly Bolt the Housing on to the Mounting Structure
Attach the housing to the mounting surface with bolts, but don’t tighten fully yet. Bridge over the housing mounting bolt slots with heavy washers, or heavy spring lock washers. This may help prevent loosening.
4. Establish the Final Mounting Position
Before securing the bolts, establish your final mounting position by aligning the bearing units by hand or a rubber mallet.
5. Securely Bolt the Housing to the Mounting Structure
Once the bearing is properly aligned, securely bolt both units to the mounting structure.
6. Ensure the Shaft can Move Axially
Ensure that the shaft can move axially through the bearing bores to confirm proper alignment. If this cannot be done, loosen the housings and realign the shaft.
7. Tighten Both Collar Set Screws
Tighten both collar set screws. Once tightened, rotate the shaft and alternately tighten to the manufacturer recommended torque values. If a torque wrench is not available, tighten the set screws until a permanent twist is established with an Allen wrench.
8. Install the Expansion Unit (If Necessary)
If you are using an expansion unit, always lock the fixed bearing first. Move the expansion bearing axially to center in the housing. Once centered, alternately tighten the set screws on the expansion unit as you did on the fixed unit.
For more information, check out Regal Rexnord's industry-leading bearings products.
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Mark Czubak
Mark Czubak is a Principal Engineer with the Regal Rexnord Bearing business. He has spent nearly 40 years with Rexnord where he has managed all facets of engineering, including application, design and manufacturing, giving him a cradle to grave knowledge of mounted roller bearings. With this experience, Mark shares his passion and knowledge through bearing training, application assistance and installation. “Bearings are overlooked for the more expensive components of the system, but a bearing failure can cause just as much downtime as any other component so choose your bearings wisely and save time and money.”
Page last Updated: November 21, 2025