Grease Zerk Fittings to Keep Things Running Smoothly

Four Grease Zerk Tools for Fighting Friction

Grease Zerk Fittings to Keep Things Running Smoothly

Reading Time: 6 minutes

When and how to grease Zerk fittings is something many of us don’t think of often, but regular greasing is a crucial part of routine maintenance for your tractor and other critical equipment. Homesteading today still requires us to do lots of things ourselves, including the mundane tasks of greasing the squeaky wheels around the farm. I’ve been greasing equipment for longer than I care to remember, and I’ve learned a few things about these elusive little fittings, but first let’s explain exactly what is a Zerk fitting.

What’s a Zerk?

Zerk fittings are found wherever grease is required. It could be a needle bearing in a universal joint, a ball joint, a pin that allows parts to rotate or an area that has two hard surfaces that slide upon each other. There are Zerks on your tractor, your car, truck, bush hog, log splitter, and even some wheelbarrows. They’re everywhere, especially on old tractors like in our compact tractor comparison article.

In a nutshell, the actual Zerk fitting is a small nipple that threads into a hole. That nipple has a ball bearing in the tip that keeps grease in and keeps contaminants out, but its design allows grease guns to push fresh grease into the fitting. When you grease Zerk fittings it allows you to deliver lubrication to the hard-to-reach component where it’s installed.

This universal joint has a threaded hole to screw the Zerk fitting into (pictured above)

Different Zerks for Different Applications

Most Zerks are in a precarious position, and access may not be easily gained. To compensate for weird angles and obstructions when you grease Zerk fittings, they come in different angles such as 90°, 45°, 22° and straight fittings so that, if needed, you can install an angled fitting to make your life easier.

Not only are there angled fittings, but there are also remote fittings which are a fantastic thing to have. Remote grease fittings are usually found clustered together, many times in the back of a tractor or other equipment. You may find a plate with five or six Zerks attached. When you grease Zerk fittings like these, you’re actually pushing grease down a long hose or tube, possibly several feet long, which leads to the area that needs to be greased. New tractors are employing these more and more so that farmers don’t have to crawl under the tractor as much to perform basic maintenance.

This Zerk fitting is recessed into the loader arm

Where to Look

Like I’ve said, Zerk fittings can be elusive little buggers. First, check owner or maintenance manuals to see if their locations are designated. If you don’t have a manual to reference, you can hunt them down. Here are a few places to check.

  • Steering Components: Ball joints, tie rod ends and other steering components need to be greased if you want them to perform smoothly or stay operational. Your steering column may also have a Zerk.
  • Drive Shaft Joints: Drive shafts and PTO shafts usually have Zerks in the body of the joints. The typical universal joint (AKA U-Joint) has a Zerk near the center of its body. When you push grease into the fitting, the grease gets delivered to the ends of the body where the spindle bearings reside.
  • Loader Arms: Your tractor’s loader arms rotate on pins. Without grease, these metal on metal connections will creak, groan, grind and seize. On a tractor, these are usually the most vocal when they run dry, but avoid the squeaky wheel syndrome by keeping them greased. Be aware that it’s commonplace for some Zerks to be recessed into the loader arms, so check holes to see if they’re actually access points for greasing Zerk fittings.
  • Hydraulic Pistons: Hydraulic pistons or cylinders are on all sorts of things. Your loader arms are moved by them, your log splitter has one and every modern backhoe has them. Either end of these pistons rides on a pin, and that rotating surface needs to be greased.
  • 3-Point Hitch: Your top link, adjustable hitch arms and various other joints in the area of your 3-point hitch should have Zerk grease points. Greasing these and working them regularly will ensure that you can adjust them when you need to without an inordinate amount of effort.
This mini pistol grip grease gun is my favorite tool for a quick 1 or 2 fittings

Tools of the Trade

The concept of greasing Zerk fittings is simple, the action of reaching them can be difficult. There are a few tools I’ve found to be quite useful, and a few that are more hype than help.

  • Standard Size Grease Guns: Every mechanic in America has one of these lurking in their shop. These tools hold a full tube of grease and offer enough leverage to make it easy to produce pressure when pushing grease into stubborn fittings. Unfortunately, they are unwieldy when crawling under things and almost require three hands to operate. These are great when they have a long hose and a swivel or 90° head. I’ll use these when I need to thread the hose into a tight spot when I grease Zerk fittings.
  • Mini Pistol Grip Guns: These small and agile grease guns are great for crawling around and under equipment, but they run out faster because they hold much less grease. I like having two of these; one with a short non-flexible head and another with a 12” hose with a straight head. These two conquer most of what I encounter on the farm really well, just be sure to stock up on refill tubes.
  • Electric Grease Guns: This is the cat’s meow when you grease Zerk fittings. Use a cordless grease gun when you’re going to be greasing a lot of fittings, or when your hands just don’t work like they used to work. They’re far more expensive than a $10 mini pistol grip, but they save you so much hand fatigue and make it easy to maintain your equipment.
  • Rejuvenator: Sometimes neglected Zerk fittings seize or plug up. There are tools meant to clear these fittings usually called “grease fitting tools” or “fitting rejuvenators.” Typically they are two-piece affairs that require you to load them with grease or diesel fuel, place them on the fitting and then strike them with a hammer to produce lots of pressure to clear the blockage. Sometimes they work, sometimes they don’t. Good ones are not cheap, and cheap ones are not good, generally speaking. If the Zerk is in a bear of a spot, then a rejuvenator may be your best bet.
  • Replacement Zerks: Your local auto parts store, tractor dealer or farm store will likely offer an assortment pack of Zerk grease fittings. When fittings get smashed, rubbed, snapped, seized or plugged, I simply replace them and call it a day. They are cheaper than buying a rejuvenator and unless I can’t access the fitting, it’s easy to replace a Zerk.
Even my wheelbarrow has Zerks in the axle’s pillow blocks

Tips for Greasing Zerk Fittings

  • Listen for the Crack: When you grease Zerk fittings, listen for the crack. Once you have filled a void full of grease, the seals on either end usually make a crackling sound as they give way to let the overabundance of grease exit the joint. Stop before you blow out the seal.
  • Use Just Enough: Don’t overfill when you grease Zerk fittings. Usually, three or four pumps of grease are enough and over-greasing a joint pushes grease out the aforementioned seals, which attracts dust, sand, and dirt. Contaminated grease can damage moving parts, so avoid having excess squish out the seals.
  • Keep them Clean: Carry a rag to clean off the Zerk after you grease. Again, exposed grease attracts dust, sand, and dirt. Avoid pushing contaminated grease into your fitting next time by cleaning it off when you grease.
  • Choose the Right Product: Not all greases are created equal. Find which kind of grease is recommended by the manufacturer for that fitting. Does it need a low-temp or high-temp grease? Crude base or synthetic? When in doubt, check.
  • Consider Compatibility: Not all greases are compatible. Don’t mix greases because they don’t all play well together. Be sure to stay consistent since mixing the wrong greases can cause reactions that result in more harm than good.
  • Wear Gloves: Disposable exam or mechanic’s gloves are perfect for greasing Zerk fittings because you’re bound to get your hands covered in grease. I may change gloves two or three times while I’m greasing Zerk fittings on a machine just because it gets hard to grab tools. It’s far better than a rag or scrubbing your hands.

The Simple Act of Greasing

It really is as simple as pushing the grease gun’s fitting onto the Zerk (firmly), giving it a few pumps and pulling it back off. Done! Clean up and move on. It’s even easier than adding tractor tire fluids or hooking up your implements.

Did you find these tips helpful? Do you have a few tips of your own? Share in the comments below!

One thought on “Grease Zerk Fittings to Keep Things Running Smoothly”
  1. Hi to all maintenance people,
    I would like to point out a little mistake we all(?) say on occasions.
    There is a big difference between a ball bearing and a bearing ball.
    Happy greasing,

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