Grease zerk fitting size

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Gwilkrrs
430 crawler
430 crawler
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Joined: Sun Mar 06, 2022 4:51 pm
Location: maryland

Grease zerk fitting size

Post by Gwilkrrs » Sat Dec 31, 2022 12:56 pm

Does anyone know the size of the grease zerk in the track adjuster?
I put my track back on and tightened it and noticed after pumping grease into the zerk it was weeping back out slowly thru the zerk nipple, after letting it sit a few days I moved the machine and the track loosened and when I looked all the grease had escaped, so I guess the zerk didn’t reset allowing weepage
I don’t know the thread size of the zerk to replace it?

Jim B
350 crawler
350 crawler
Posts: 2080
Joined: Sun Nov 05, 2017 11:36 am
Location: western Maine

Re: Grease zerk fitting size

Post by Jim B » Sat Dec 31, 2022 1:28 pm

1/8 male NPT, if I remember right. You need to be sure to get one that will hold pressure, some will not. Good brand name ones should be ok. Lincoln, Alemite, etc.

Gwilkrrs
430 crawler
430 crawler
Posts: 54
Joined: Sun Mar 06, 2022 4:51 pm
Location: maryland

Re: Grease zerk fitting size

Post by Gwilkrrs » Mon Jan 02, 2023 2:41 pm

The zerk side is likely 1/8 but not the thread size-
The book says item 10 is jd7828fitting 1/8”x3/4”
I looked up this part number and it shows as a button head zerk- not what is on the machine or anything I have ever seen-
?

Jim B
350 crawler
350 crawler
Posts: 2080
Joined: Sun Nov 05, 2017 11:36 am
Location: western Maine

Re: Grease zerk fitting size

Post by Jim B » Mon Jan 02, 2023 4:10 pm

Yes, the book calls it out as a Buttonhead, many have been changed to regular zerks over the years to eliminate having a buttonhead grease gun end adapter or a separate buttonhead gun around. Buttonheads were common on rollers and idlers as well years ago. Buttonheads aren't zerks (aka hydraulic grease fittings). While not as many thread sizes are used, buttonheads can have different size threads the same as the zerks.

Image

Are you sure it is not 1/8" NPT male thread, which would look about the size of a 3/8" fine thread bolt? The 3/4" may be referring to the overall length, the button diameter, or the hex for the wrench, different vendors show different locations for the 3/4". I think JD used the 3/4" overall length and the button diameter was about 5/8". The Buttonhead in the picture is 3/4" OAL.

You can use a common 1/8" male NPT zerk grease fitting, then you do not need to have a buttonhead gun end around. Just be sure you don't get one that allows the ball to release pressure. The part number for the 1/8 NPT zerks use on later machines is T45588 which subs to JD10510, if you want to go for JD fittings. Lincoln and Alemite have fittings that hold pressure, ask your local parts store to look at the specs for the fittings they have in stock, they should be able to find a pressure rating. You could call Lavoy he likely has suitable fittings in stock. Be careful taking the fitting out, if one leaks, as the track puts pressure on the adjuster and can cause it to blow out near the end of the threads. Likely your zerk got dirt in it or is damaged preventing the ball from seating.

Gwilkrrs
430 crawler
430 crawler
Posts: 54
Joined: Sun Mar 06, 2022 4:51 pm
Location: maryland

Re: Grease zerk fitting size

Post by Gwilkrrs » Tue Jan 03, 2023 9:36 am

i bet you are correct-
3/4" length
i have never used/seen a button head so this makes more sense now-
thanks i will try one of them.
i took the fitting out and cleaned it and the ball seemed to work but once i put it back on and tried it was squirting out again so it definitely isn't ok....

Jim B
350 crawler
350 crawler
Posts: 2080
Joined: Sun Nov 05, 2017 11:36 am
Location: western Maine

Re: Grease zerk fitting size

Post by Jim B » Tue Jan 03, 2023 11:20 am

If you are going to use a buttonhead fitting, you will need to get an end for your gun hose to fit it. My 450E calls for and uses zerks, I wouldn't change to a buttonhead. Get brand name zerks, not the hardware store kit ones and you should be fine, without going to a buttonhead. JMHO

Gwilkrrs
430 crawler
430 crawler
Posts: 54
Joined: Sun Mar 06, 2022 4:51 pm
Location: maryland

Re: Grease zerk fitting size

Post by Gwilkrrs » Tue Jan 03, 2023 12:54 pm

Thanks I will look for a name brand zerk (not sure what that is really) and not be going button head style.

Jim B
350 crawler
350 crawler
Posts: 2080
Joined: Sun Nov 05, 2017 11:36 am
Location: western Maine

Re: Grease zerk fitting size

Post by Jim B » Tue Jan 03, 2023 2:04 pm

Alemite and Lincoln are a couple of the brand names. A good auto parts store should have one or the other, often in packs of 5 or 10. Make sure they don't give you a grease/pressure release ones.

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