Cross-Threaded Zerk

[SoDark]

Alright, so this isn't exactly a tractor issue, but it's pretty close... Yesterday I drug out my JD D130 mower and was doing the spring maintenance routine. While greasing, I once again had trouble greasing the front axle pivot zerk. Every time I grease, this one always gives me trouble. Decided to tinker with it and realized that the grease wasn't actually flowing out around it; the zerk itself is fine. It's actually coming out from behind after passing through it, as it is cross-threaded. I thought it odd that it was angled as it was... Mystery solved. This is how I got it from the factory, btw. JD QC strikes again. So how do I go about rectifying this? Should I drill it out and tap it for a bigger zerk? Not sure how I'd do so without forcing metal shavings into the cavity...

Any advice or ideas would be much appreciated!

 

[Zebrafive]

Try a new zerk, old one might have all the thread damage. If that does not work, chase the threads of the tractor with the correct tap. Grease the tap and chips should stay with it.

 

[Sawyer Rob]

Chase the threads with the proper size "bottoming" tap, and install the zerk...

You can always clean everything up good, and use a little blue loc-tite to seal the tap in better.

SR

 

[DJ54]

I checked through JD parts, that fitting is a 1/4" X with 28 tpi, which is not in a standard tap & die set. I got mine at NAPA, and keep it in the zerk drawer, in my tool box.

Here is the part description, and part number through the Green part store. John Deere 1/4-inch-28 Straight Grease Zerk - JD7844

 

[Shaneard]

I checked through JD parts, that fitting is a 1/4" X with 28 tpi, which is not in a standard tap & die set. I got mine at NAPA, and keep it in the zerk drawer, in my tool box.

Here is the part description, and part number through the Green part store. John Deere 1/4-inch-28 Straight Grease Zerk - JD7844

1/4-28 is a standard size, it's just fine thread 1/4". Any decent tap and die set would have this included. A 1/4-28 grease zerk can be had from anywhere that carries grease fittings. I wouldn't get one from JD, you can buy a whole pack somewhere cheaper than you can buy one from JD probably.

As far as the cross threaded zerk, check the fitting like others have said, otherwise you can always drill it out and tap it to a 1/8" npt pipe thread and get a new zerk.

 

[def38]

I would guess that the Zerk fitting itself is a softer metal that the threaded piece it screws into. Therefore, you may find the female threads are not damaged. Only the Zerk male threads are damaged. As mentioned by others, Zerk fittings are sold everywhere. I bought mine on Ebay (mine are metric), Got ten of them for a few bucks, free shipping.

 

[DJ54]

1/4-28 is a standard size, it's just fine thread 1/4". Any decent tap and die set would have this included. A 1/4-28 grease zerk can be had from anywhere that carries grease fittings. I wouldn't get one from JD, you can buy a whole pack somewhere cheaper than you can buy one from JD probably.

As far as the cross threaded zerk, check the fitting like others have said, otherwise you can always drill it out and tap it to a 1/8" npt pipe thread and get a new zerk.

My bad, I was thinking 1/4' X 26 tpi, which is for some metric fittings on something I have around here... British Thread Grease Nipples | 1/4"-26 BSF Grease Nipples

 

[ruffdog]

Some zerk fittings have a short threaded length, some have a longer threaded area. If you retap the hole and get the longer threaded zerk, you should be ok.

 

[SoDark]

Appreciate everyone's input! I finally got back to it in between jobs and hospitals, and went over options and suggestions and ended up just wrapping the threads with a few layers of thick plumbing tape. Seems to have done the trick. Time will tell... I bought a collection of various size SAE and Metric grease fittings, and laid down with my tap and drill set, then figured I'd try the Teflon before removing metal. If this fails, I'll drill it and tap it straight.

An annoying factory flaw... But certainly not the worst.

 

[bigtiller]

A self tapping zerk takes all the work out of it.

 

[ruffdog]

A self tapping zerk takes all the work out of it.

They are not really "self TAPPING" as they are just a tapered thread like a normal zerk. You just drive it into a larger hole....probably what the manufacturer used to begin with and why it was crooked.

 

[bigtiller]

They are not really "self TAPPING" as they are just a tapered thread like a normal zerk. You just drive it into a larger hole....probably what the manufacturer used to begin with and why it was crooked.

Working on new agricultural implements for 30 years, I have put hundreds of self tapping zerks in. Never seen a threaded hole for a zerk. They work.

 

[ruffdog]

I'm just the opposite....all the machine shops I worked at, we always drilled and tapped for zerks. The only ones we didn't tap for were applications that specified pressed in zerks. Also, I've been working on equipment for 40 years and the "self tapping" zerk was new to me.

Thread forming fittings do not cut threads like a tap does. They have hardened threads that drive into the hole and form threads like a roll tap would. For you to be able to get a TFF into a hole, it must be larger than the hole if you plan to use a tap. The hole for a TFF is a 15/64 (.234) and the #3 tap drill for a 1/4-28 is (.213).

Once the threads are in the item the zerk screws into, either zerk fits the same.

Thread Forming | American Lubrication Equipment