Oil Seal Installation: A How To

Oil Seal Installation: A How To

One of the main principles of power transmission is consistent lubrication. Shaft seals play a hugely important role in this. Imagine a situation involving a shaft-mount reducer – electric motor prime mover, driven by belts, motion controlled by a torque arm – with an improperly seated seal. A blown-out input shaft seal is a nightmare situation, necessitating an entire breakdown and reassembly, not to mention re-aligning and re-tensioning the belts.

The oil seal is our first line of defense in regards to keeping lubrication inside the reducer. It might also be described as the last line of defense – keeping contaminants outside the reducer where they belong. The average seal is incredibly simple in design – made up of a case, a lip or lips, and frequently a garter spring. Of course, some are exponentially more intricate and are manufactured with unusual materials, but the majority are straightforward.

The care taken during the installation process will pay off by allowing the seal to work quietly and operate efficiently behind the scenes of your application.

Prepping for Oil Seal Installation

Before you begin the installation process for any power transmission component, the first goal is making sure everything is clean and free of any material flaws such as nicks, burrs, scratches, dents, et cetera. Most of these components have very tight tolerances, so maintaining this accuracy is important in their performance. This is especially critical for oil seals because of their function.

Begin with a thorough inspection of all involved surfaces: shaft sealing surface and housing bore, seal lip(s), and outside diameter. Maintaining the integrity of the sealing lips is “Priority 1″. The slightest tear or nick can develop into a more significant issue during operation.

Over time, the seal lip(s) will wear a shallow groove into the shafting due to the pressure the seal imposes upon it. Visible scoring on the shaft indicates a genuine possibility that the seal will not perform as well as intended. The potential for lubricants leaking out and particulates working their way through the seal drastically increases when placed over a worn location.

There are a few options to remedy this situation:

Using a spacer to move the seal forward is a possibility, assuming there is enough room in the housing bore to allow a shift. Ideally, the seal outside diameter (OD) should be in full contact with the housing.

There are also shaft repair sleeves that can add a “new surface” to the shaft. Measuring a few thousandths of an inch in thickness, they cover shaft flaws so the seal can make proper contact with the surface.

Probably the least appealing solution is to either replace or refinish the shafting. In some cases, this is not possible; in others, it could benefit the application in the long term.

Which option is best? This decision is left entirely to you. Whatever solution you choose, the seal needs a proper fit to function.

With the application cleaned and the components ready, you’ll begin your installation.

Oil Seal Installation

Many seals come with a garter spring, found within the backside of the seal. It provides contracting pressure against the sealing surface. Making sure the spring seats correctly within the seal is an excellent first step.

Next, apply a small amount of grease to the seal lip(s) and the area of the shaft in contact with the seal.  When using a double-lip seal, fill the small cavity between the two lips with grease as well. This both protects the lips during initial installation and break-in, and also acts as another barrier keeping contaminants out. When installing rubber-coated seals, apply lubricant to the outside diameter as well. This will help prevent the seal from rebounding or backing out from its mounting place.

Orient your seal the same way as the initial install. The sealing lip should face the lubricant that requires sealing. The second lip on a double lip oil seal is intended as a dust lip. The seal must be installed at a 90°, or perpendicularly, to both the shaft and housing bore. This is an issue in cases where the housing does not have a counterbore or shoulder the seal can seat up against.

When a seal is angularly misaligned – or cocked on the shaft – an irreversible process begins. Excessive pressure on one section of the seal, when not installed properly, can cause the spring to become dislodged or the seal to heat up and become brittle through excessive wear, both leading to a premature failure.

Some Tools Required During Installation

In situations where the shaft has splines or an integral gear on the end, you’ll want to take precautions. These gears and splines often have very sharp edges that are quite detrimental to the seal’s integrity. You may use an installation sleeve that will allow the seal to slide past these hazards undamaged.

The last step involves the actual pressing-in of the seal. There are tools and tool kits available that can help with seal installation. Their biggest benefit is that they apply a very uniform force to the seal case, eliminating the possibility of the seal seating in any way other than flush.

If these specific tools aren’t available, it’s entirely possible to correctly seat an oil seal in its housing using a hammer. Ideally, this hammer will be plastic or rubber due to it’s more forgiving nature. Using this and a strike plate that covers the entire seal will lend you accuracy while driving it in. The downside to this method is the inability to drive the seal any further than the strike plate will allow.

The small little oil seal has an outsized role in power transmission.

Proper techniques and diligence during oil seal installation will result in what seems like an unremarkable situation – a component holding its lubrication. When something you’ve installed works effectively and quietly, you know you’ve done it right.

Want to find an oil seal or shaft repair sleeve for your application? Visit the Durus website.

Why is Proper Lubrication Important for Seal Components?

If your machines or equipment aren't making sounds, you and your co-workers probably haven't thought a whole lot about lubrication. I mean, why would you? That mindset happens for a lot of people working on the factory floor or the machine shop.

But you don’t have to wait until your gears are all rusty and worn out before you use lubricants. In fact, it’s better to lubricate regularly the seal components of your machines. Proper lubrication:

Reduces friction and heating of moving parts

Prevents premature wear and tear of seal components

Maintains the integrity of machines and other industrial applications

Machineries operate better when the seal components are lubricated. There’s less resistance and chafing, so the parts last longer. Some seals are prone to cracking easily, but when they are properly lubricated, they don’t snap just as easily.

Not all lubricants are the same.

Lubricant, oil, and grease. What’s the difference between the three?

People like to use those terms interchangeably, and they are somewhat correct in doing so. However, lubricant is an umbrella term for both grease and oil. For purposes of clarifying what a lube really is and what it does, let’s establish their differences.

The difference between the oil and grease lies in their application:

If you have machines that operate at high temperatures and speed, use

oil.If your machine operates at regular temperature and speed, use

grease.

That’s the most basic explanation. But of course, there are specific types of lubricants for specific types of operations:

Introduction to Oil Seals and How They Are Used - Bearing-Belt and Chain Inc.

There are a variety of oil seals used in a variety of applications to help close the space between a stationary and a moving part.  By closing the space it prevents any lubricants from escaping.  Additionally, oil seals help create a seal that prevents any contaminants from entering machinery which can cause a host of problems.  Mechanical equipment and machinery require different size or type oil seals to ensure that there is a superior and precise seal.  Because oil seals help reduce contamination or mixing of materials it prolongs the life of machinery and helps ensure a more reliable performance.

There are a wide variety of industrial applications and therefore there are a wide variety of oil seals to meet the specific application needs.  By choosing the right oil seal you will have a better fit, improved stability, and enhanced reliability.  Rubber tends to be one of the most commonly used oil seal materials. SKF, an oil seal manufacturer, explains how oil seals for and the importance of proper installation, “To provide effective sealing, radial shaft seals must be installed properly. An experienced installer with suitable tools, working in a clean environment, is recommended to provide proper installation. The shaft counterface surface and housing bore should meet the demands specified in the sections Shaft requirements and Housing bore requirements. To facilitate seal installation and to achieve initial lubrication, prior to installation, SKF recommends wiping the shaft and seal with the lubricant that is going to be retained. While the outside diameter of metal-cased seals can be lightly lubricated to ease installation, the outside diameter of rubber covered seals should always be lubricated.

Seals with an auxiliary, contacting lip can also be filled with grease between the sealing lip and auxiliary lip to reduce frictional moment. This does not apply to silicone rubber seals and seals with hydrodynamic features, other than SKF WAVE lip designs. SKF also recommends using a hydraulic press, with suitable tools, to install a seal in its housing bore. Pressure should be applied as close as possible to the outside diameter of the seal.”  Oil seals are commonly used in a variety of industries. Below are 5 types of oil seals used in today’s manufacturing and machinery industry.

5 Types of Oil Seals

Automotive

Industrial

Mechanical

Oil & Grease

Shaft