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A grease nipple is a one way valve. It lets you pump fresh grease into moving components while keeping dirt and moisture out. These small fittings provide an easy access point for applying lubrication to bearings, bushes and other moving parts. They play a crucial role in keeping your vehicle running smoothly.
Grease nipples are found on many vehicles and mechanical assemblies. Their location and design can vary, but the basic job remains the same. Regular greasing reduces friction and extends the life of your vehicle. This post covers everything you need to know about grease nipples.
Key Takeaways
- A grease nipple is a small fitting that lets you apply lubricant to moving parts.
- It contains a spring loaded ball bearing that acts as a one way valve.
- They work with a grease gun to deliver lubricant under pressure.
- Regular greasing reduces friction, wear, and helps prevent breakdowns.
- Grease nipples come in straight, 45 degree, and 90 degree angles.
What Is a Grease Nipple?
A grease nipple is a small metal fitting that allows you to add grease to a mechanical component. They are usually screwed into a threaded hole. A grease gun is attached and used to force grease into the joint or bearing housing. The nipple’s job is to provide an easy and effective entry point for the lubrication. They are also known as grease fittings, lubrication fittings and grease nipple fittings.
Inside a typical grease nipple is a small spring loaded ball. This acts as a valve. When the grease gun applies pressure, the ball moves and allows grease to pass through. When pressure is removed, the ball returns to its original position. This prevents dirt and moisture entering the lubrication point. And, it prevents grease from escaping.
Grease nipples are common on vehicles and machinery where regular lubrication is required. They can be found on components such as suspension joints, steering parts, pivot points and bearings. Without a grease nipple, you would have to dismantle the joint to apply lubricant. The fitting makes routine maintenance quick and straightforward. You can service a joint in seconds with the right tools.
How Does a Grease Nipple Work?
A grease nipple works as a delivery mechanism for lubricant. They consist of a hollow body with a threaded base and a small opening at the tip. At the tip, a small spring loaded ball bearing creates a seal.
When a grease gun is connected, pressure is applied to the small ball inside the fitting. This pressure pushes the ball back against the spring and creates an opening. Grease can then be pumped into the grease nipple and delivered to the component it is connected to.
When the grease gun is removed, the internal spring pushes the ball back into its original position. This closes the seal, keeps contaminants out, and holds the grease in place. Grease nipples allow mechanics to deliver lubricant to areas that would otherwise be very difficult to reach.
The fitting itself does not provide the lubrication. It simply provides a controlled access to the component. And, the grease gun supplies the pressure needed to force the lubricant through the fitting.
Types of Grease Nipples: Straight, Angled & Flush
There are three main types of grease nipples: straight, angled, and flush. Each of these are available in a range of metric, UNF, and BSP thread sizes. The correct type depends on the type of vehicle and the position of the lubrication point. Other types include long series and button head fittings. Let’s take a closer look.
Straight Grease Nipples
Straight grease nipples are the simplest type. They point directly out from the surface in a straight line. No angle. They work best for components with clear, unobstructed access. They allow the grease gun to connect straight on.
Angled Grease Nipples
There are two types of angled grease fittings: 45° degree grease nipples and 90° degree grease nipples. These are used when access to the lubrication point is restricted. They have angled heads that allow you to access the nipple from a preferred angle - great when working in tight spots.
Flush Grease Nipples
Flush grease nipples sit level with the surface. The top is concave, which allows the grease gun nozzle to sit inside the recess. They are used when space is very limited or when they are close to a moving part.
Long Series
A long series grease nipple has a long extended body. They are used for lubrication points that are recessed and difficult to access. The long body provides extra ‘reach’.
Button Head
A button head grease nipple has a flat circular head. It has a unique design that allows the grease gun to slide on from the side. And, it allows a much greater flow rate of grease. They are used for applications that require large volumes of lubricant.
Overview
| Type | When to Use |
|---|---|
| Straight | Lubrication points with clear, direct access. |
| 45° Angled | Points that are slightly offset or awkward to reach. |
| 90° Angled | Tight corners or spots where a straight fitting would hit an obstacle. |
| Flush | High-traffic areas, moving parts, or any place a protruding fitting could be damaged or cause a hazard. |
What Is a Grease Gun?
A grease gun is the tool you use to apply grease through a nipple. It is a simple hand operated pump that forces grease through a hose and into the fitting. They provide a quick and controlled way to lubricate grease nipples on vehicles and workshop equipment. There are three main categories of grease gun: manual lever, pistol grip, and battery powered. Let’s take a closer look.
Manual Lever Grease Guns
Manual lever grease guns are a common choice in UK garages and workshops. They are simple, reliable and suitable for most routine maintenance and servicing jobs. The lever action allows grease to be applied under pressure through a grease nipple.
Pistol Grip Grease Guns
Pistol grip grease guns are designed for easier one handed operation. This can be useful when working in tight areas where you need to hold the grease gun with one hand and steady the hose with the other. They are suitable for a wide range of workshop applications.
Air Operated Grease Guns
An air operated grease gun uses compressed air. It reduces the manual effort of squeezing grease into the grease fitting by hand. The are a good choice for jobs that require frequent or large volumes of lubricant.
Battery Powered Grease Guns
Battery powered grease guns are a good option for busy workshops that perform frequent maintenance work. They reduce the manual effort required to operate a hand lever grease gun. And, they’re great for applying applying grease quickly.
Where Are Grease Nipples Located?
Grease nipples are located on components that have moving parts and need regular lubrication. They are most commonly found on suspension and steering systems. They are very common on older vehicles. Modern vehicles tend to use sealed components that are designed to operate without regular greasing.
Grease nipples are most commonly found around suspension joints, steering components, pivot points, bearings and linkages. Commercial vehicles, trailers and off road vehicles often have additional lubrication points. Some fittings can be hidden behind guards or located in tight spaces. These difficult to access points often use angled grease nipples, more on this below.
If you’re struggling to find grease nipples on your vehicle, check the vehicle user’s handbook or contact the manufacturer and request a lubrication chart. Do not assume every grease nipple is in an obvious position.
Why Regular Greasing Is Important for Your Vehicle
Grease reduces friction between moving surfaces in your vehicle. It creates a lubricating layer that helps components run smoothly by reducing direct contact between metal surfaces. Without lubrication, moving parts wear more quickly.
Regular greasing helps reduce wear and tear. It reduces friction and creates a barrier that protects vital components from moisture and contamination. Applying grease extends the service life of your vehicle.
How often should you add grease? There is no single answer. It depends on the vehicle, the component, and how you use the car. For modern cars, many suspension parts are sealed and need no greasing at all. But if your car has serviceable joints, a regular schedule is vital.
The correct maintenance schedule depends on the vehicle and component. Some vehicles require regular greasing, while others use sealed parts that do not have serviceable grease nipples. Follow your manufacturer's guidelines for the safest approach.
How to Choose the Right Grease Fitting for Your Vehicle
Choosing a type of grease nipple comes down to thread size and angle. First up, the nipple must fit the hole you are screwing it into. And, it must point in a direction that allows you to easily attach a grease gun.
Thread Size
Thread size is critical. It must match the component you are attaching the grease fitting to. The most common thread sizes are 1/8 BSP, 1/4 BSP, 1/4 UNF, M6, M8 and M10. BSP stands for British Standard Pipe. And, UNF stands for Unified Fine - an American standard.
Straight vs Angled
You also need to consider if the shape of the nipple. This boils down to the level of access to the lubrication point. Straight nipples work best if you have clear ‘straight-on’ access to the area. However, if space is restricted, you’ll need to use an angled grease nipple.
How to Apply Grease
Greasing a nipple is simple when you know how. Here are a few simple tips to make sure it runs smoothly. The first thing you need to do is clean the nipple. Wipe away any dirt or old grease from the tip using a clean rag. This prevents contaminants from being forced into the grease fitting.
Next, check the grease gun and make sure it contains the correct type of grease. Attach the grease gun coupler to the nipple. Push it on squarely and make sure it is securely attached. Then, pump the grease slowly and steadily.
Pump the grease gun until you see a small amount of old grease emerge from the joint. This is the sign that fresh grease has reached the bearing. Do not overfill the component. A small amount of grease escaping is usually enough.
Once you are done, carefully remove the grease gun coupler. Wipe away excess grease and clean the area around the fitting.
How Often Should You Grease Them?
How often should grease nipples be greased? There is no straight forward answer to this question. It all depends on your vehicle, the component, and how you operate the vehicle. For example, many modern cars have suspension parts that are sealed and don’t require greasing. Others have serviceable joints that require regular greasing.
In general, classic cars and off-road vehicles require regular greasing. Classic cars are typically greased once a year, or every time they are serviced. Off-road vehicles require more attention. Mud and water can displace grease and trigger corrosion. These vehicles are greased several times each year depending on use.
Your best bet is to check your owner’s manual. If you don’t have one, get in touch with the vehicle’s manufacturer. They should be able to give you some clear recommendations. Ideally, try to get your hands on the vehicle’s lubrication chart. This will list all the lubrication points and the required greasing intervals.
Common Problems & How to Fix
Grease nipples can fail in a few different ways. Let’s take a look at the most common problems and how to fix them.
Clogged Grease Nipple
The most common problem is a clogged nipple. Old grease and dirt can harden inside the fitting. This blocks the internal passage and prevents grease passing through. The best way to fix the issue is to apply heat. You can use a heat gun or propane torch to soften the hardened grease. Be careful not to damage any rubber seals.
Cross Threading
If the nipple is cross threaded it will not seal properly. Grease will leak out around the base of the fitting. You’ll also struggle to tighten it fully. This usually happens when you use too much force when attaching the nipple. The best advice is to screw the nipple by hand, and only use a spanner for the final turns.
Stuck Valve
Another common issue with grease fittings is a stuck valve. Once the valve is stuck, you can't apply any grease to the component. The best fix is to gently press the valve a fine screwdriver or bit. A small poke usually sets it free. If not, you’ll need to replace with a new nipple.
Grease Gun Won’t Detach
This issue is more common than you might realise. Sometimes the grease gun gets stuck on the nipple. If this happens, try angling the hose as you try to free it. A small twist helps disengage the coupler. Do not attempt to remove with brute force.
