Zerk fittings
Thread Starter
Intermediate
Joined: Aug 2020
Posts: 33
Likes: 1
From: MI
Zerk fittings
I have tried to grease my 78 front end suspension ball joints. Grease only goes around the fitting and external surface. It does not appear like grease is entering the ball joint. A local mechanic said first try to replace the zerk fittings before changing the ball joints.
I purchased new generic zerk fittings at the local Advanced Automotive store. They don't have anything Corvette specific. The fittings at 1/4" by 28 thread. It looks like the fittings I removed from my car.
They don't thread in to the joint. It looks like the thread on the Corvette fittings is 28, but tapered. It could be some other measurement or I need specific fittings from a 78 Corvette.
What do you think? Is there a vendor I can visit to obtain appropriate Zerk fittings.
While I'm creating this post, the original fittings are soaking in brake fluid. I'm giving that a try.
I purchased new generic zerk fittings at the local Advanced Automotive store. They don't have anything Corvette specific. The fittings at 1/4" by 28 thread. It looks like the fittings I removed from my car.
They don't thread in to the joint. It looks like the thread on the Corvette fittings is 28, but tapered. It could be some other measurement or I need specific fittings from a 78 Corvette.
What do you think? Is there a vendor I can visit to obtain appropriate Zerk fittings.
While I'm creating this post, the original fittings are soaking in brake fluid. I'm giving that a try.
Race Director
Joined: Nov 2006
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From: Sunshine Coast, Queensland, Australia
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Cruise-In VIII Veteran
Try soaking them and then with a little pick, see if you can depress the little ball in the center. Sometimes they jamb up. Free the little ball and you should be good.
they sell zirks in pipe thread, different sizes of pipe thread. Metric threads, course threads, press in style, you name it. So yes you can get replacements.
but freeing up the little check ball should do.
they sell zirks in pipe thread, different sizes of pipe thread. Metric threads, course threads, press in style, you name it. So yes you can get replacements.
but freeing up the little check ball should do.
1967 Pedal Car Champion
Joined: Mar 2020
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From: US-PNW
There isn't much to a Zerk fitting that can fail... I'd think a brake cleaner or mineral spirits would do better than brake fluid for cleaning grease — not sure of the dissolving qualities of brake fluid other than on paint. 
After cleaning and "exercising" the little plunger ball, push each Zerk into the grease gun nozzle and give it a squirt to make sure the fitting is open and flowing.
With the Zerk removed from the ball joints, put a toothpick or bamboo skewer into the hole to see how stiff the current grease is. If it's really old, it may be relatively solid and not allowing the new grease to push it out of the boot.
After cleaning and "exercising" the little plunger ball, push each Zerk into the grease gun nozzle and give it a squirt to make sure the fitting is open and flowing.With the Zerk removed from the ball joints, put a toothpick or bamboo skewer into the hole to see how stiff the current grease is. If it's really old, it may be relatively solid and not allowing the new grease to push it out of the boot.
Thread Starter
Intermediate
Joined: Aug 2020
Posts: 33
Likes: 1
From: MI
The ball plunges down on the zerk fitting. I learned the nozzle on my grease gun rotates to allow easy on/hard off of the zerk. So I placed the clean fitting back onto the ball joint, tightened the gun nozzle onto the fitting. When I pump, grease still builds up around the fitting.
So, I don’t know if I need a different nozzle, new fittings(which I don't know where to get, or something else.
When I probe the ball joint without the fitting in place, I retrieve no grease from the bearing.
So, I don’t know if I need a different nozzle, new fittings(which I don't know where to get, or something else.
When I probe the ball joint without the fitting in place, I retrieve no grease from the bearing.
There isn't much to a Zerk fitting that can fail... I'd think a brake cleaner or mineral spirits would do better than brake fluid for cleaning grease — not sure of the dissolving qualities of brake fluid other than on paint. After cleaning and "exercising" the little plunger ball, push each Zerk into the grease gun nozzle and give it a squirt to make sure the fitting is open and flowing.
With the Zerk removed from the ball joints, put a toothpick or bamboo skewer into the hole to see how stiff the current grease is. If it's really old, it may be relatively solid and not allowing the new grease to push it out of the boot.
After cleaning and "exercising" the little plunger ball, push each Zerk into the grease gun nozzle and give it a squirt to make sure the fitting is open and flowing.With the Zerk removed from the ball joints, put a toothpick or bamboo skewer into the hole to see how stiff the current grease is. If it's really old, it may be relatively solid and not allowing the new grease to push it out of the boot.
Melting Slicks
Joined: Oct 2000
Posts: 2,142
Likes: 195
From: Englewood FL
You could purchase another grease gun zerk coupler and thread it onto your grease gun and see if that works. The grease gun zerk couplers either have three or four prongs that grab onto the zerk fitting. I prefer the ones that have four prongs. Perhaps yours is worn so it is not making a seal, even when tight. The ball joints often have an expandable rubber boot, which takes little pressure to expand.
Zerk coupler
Zerk coupler
Last edited by mark79,80; May 25, 2024 at 08:32 PM.
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That's what I was thinking. Old hardened grease is what usually plugs a zerk.
Race Director
Joined: Nov 2006
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From: Sunshine Coast, Queensland, Australia
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Cruise-In VIII Veteran
Have you simply tried putting one of the new zirks that don't fit your car onto your grease gun? Will it pump grease through the new zirk?
Thread Starter
Intermediate
Joined: Aug 2020
Posts: 33
Likes: 1
From: MI
Found the problem. As 4-vettes suggested, I tried the grease gun on a new zerk fitting. Grease spilled out around the fitting. So I purchased a new connector from hose to zerk fitting. This one has 4 ring clips. Worked perfectly. Greased all 10 fittings I could find. Some took a lot of grease before they leaked any of the old, yellow/gray grease from previous greasings. I bet they'd not been greased for 2 decades. I plan to repeat a greasing after a month of driving, thinking that should remove most of the old grease and replace with new.
Thanks for all your timely suggestions and interest.
Thanks for all your timely suggestions and interest.
