Ford LGT K321 oil drain plug

Mad Farmer

Well-known Member
Location
Northeast
That is a two part drain plug. Reducer screws into oil pan and plug screws into reducer. Both are brass and they are rounded off now.

Anyway anybody know thread sizes? This is a 1972 tractor
 
(quoted from post at 12:08:21 08/09/22) That is a two part drain plug. Reducer screws into oil pan and plug screws into reducer. Both are brass and they are rounded off now.

Anyway anybody know thread sizes? This is a 1972 tractor

I would think that was a ''field repair''.

Does a 1/2'' pipe plug fit with the reducer removed?
 
Not a field repair. My parents bought the tractor new in 1972 and I've done all the oil changes. I want to be sure I can find parts before hand as last time almost couldn't remove the plug.

The reducer takes an 11/16 socket and the plug is a square head 3/8. The 3/8 plug got rounded off last oil change, and you have to hammer the 11/16 on to the reducer as there is not enough room between it and the pan. I don't want to grind one of my 11/16 sockets down to get it to fit.
 
(quoted from post at 13:15:48 08/09/22) Not a field repair. My parents bought the tractor new in 1972 and I've done all the oil changes. I want to be sure I can find parts before hand as last time almost couldn't remove the plug.

The reducer takes an 11/16 socket and the plug is a square head 3/8. The 3/8 plug got rounded off last oil change, and you have to hammer the 11/16 on to the reducer as there is not enough room between it and the pan. I don't want to grind one of my 11/16 sockets down to get it to fit.

Got a photo?
 
I just worked on a K161 that has 1/2 pipe thread drain plugs in it. I would think a K321 would use 1/2 pipe thread holes in their sumps too.

P.S. If you want to avoid a lot of pain in the future, put a steel plug and/or reducer in there. Brass tends to weld itself to the cast. The only drain on one of those that I couldn't get out was a brass plug. I almost never have problems with steel ones. If you are not worried about original appearance, there should be hex plugs available that you can remove with a regular socket.

If you go with a square plug, there are 8-point sockets made that fit those square plugs really well.
 
(quoted from post at 18:21:51 08/09/22) I just worked on a K161 that has 1/2 pipe thread drain plugs in it. I would think a K321 would use 1/2 pipe thread holes in their sumps too.

P.S. If you want to avoid a lot of pain in the future, put a steel plug and/or reducer in there. Brass tends to weld itself to the cast. The only drain on one of those that I couldn't get out was a brass plug. I almost never have problems with steel ones. If you are not worried about original appearance, there should be hex plugs available that you can remove with a regular socket.

If you go with a square plug, there are 8-point sockets made that fit those square plugs really well.

Sorry no pictures. I needed to mow stuff yesterday.

The square head 3/8 plug was not coming off with a 3/8 open end wrench it was rounding off, it's close to 1/2" thread. It won't drop in a 7/16 socket, almost fits a 1/2, and sloppy in a 9/16. My guess is some sort of 1/2" fine thread, not tapered like NPT

The reducer thread is close to 5/8 thread, no go in 9/16, loose in a 11/16 with 11/16" hex head. Again fine and don't look like a NPT.

I could get an 11/16 6 point socket on the reducer but was an interference fit up against the part of crankcase pan that hangs down; I had to tap it on with a hammer then used a 3/8 breaker bar. Had to repeat this several times as it wanted to twist and pop off. After a few turns it spun right off.

I clamped the reducer in my vice on the hex, then put a short 3/8" extension on the square head of the plug. I used a wrench on the square head of the extension (where a socket would fit) and was able to separate the plug. All the threads looked good.

At this point the dirty oil is fully drained and it's getting late. I decided to reinstall the plug assy using the 3/8 extension. I could get it good and snug and the square extension had good purchase on the 3/8 head of the plug. I didn't go gorilla on tightening it down.

Next oil change I'll use the 3/8 extension to remove the plug. Usually the adaprter comes out with it , and some pictures. That should be before end of fall.

Will get some pictures and return to this thread.

BTW, the Ford/K321 is 50 years old, and nothing has been replaced inside the engine yet, just tuneup parts, air filters and carb rebuild from when I used E10 for a while. Smokes a little but still good power.

I ran it for a few hours with fresh oil and all was good.
 
So.......if it is a 1972 Ford 140 or 145 tractor, the oil pan is cast iron and welded between the pipe frame rails.
I have 2 100s (one of which my Dad bought new in 1972), a 120 and a 145. All have a 1/2" threaded "boss" in the bottom of the pan with a single steel (cast iron) plug.
The parts manual shows a single plug as well but does not specify the size and it is "no longer serviced"
Why yours would be different, I haven't a clue.
Don't get mad Mad......but are you sure the original plug was not replaced at some time in the past 50 years with a 3/8" plug and a 3/8" to 1/2" adaptor?
 
(quoted from post at 08:35:37 08/10/22) So.......if it is a 1972 Ford 140 or 145 tractor, the oil pan is cast iron and welded between the pipe frame rails.
I have 2 100s (one of which my Dad bought new in 1972), a 120 and a 145. All have a 1/2" threaded "boss" in the bottom of the pan with a single steel (cast iron) plug.
The parts manual shows a single plug as well but does not specify the size and it is "no longer serviced"
Why yours would be different, I haven't a clue.
Don't get mad Mad......but are you sure the original plug was not replaced at some time in the past 50 years with a 3/8" plug and a 3/8" to 1/2" adaptor?

Only my father and myself ever worked on this tractor. I am sure the adapter is larger than 1/2", threads won't even fit in a 9/16" socket, just about in a 5/8, and sloppy in an 11/16"

Maybe a bad oil pan hole from the factory and this was the fix after the oil pan was already welded into the frame?

The original plug with the smaller threads was also a brass one, but it had a hex head, threads are close to 1/2". That plug head eventually rounded off and I removed it with vice grips. The whole thing came out of crankcase with insert. The only plug I could find was another brass one with the square 3/8" head. That plug worked for a few years.Adapter is original

Next time I change oil I'll post pictures.

This post was edited by Mad Farmer on 08/11/2022 at 09:01 am.
 
''the adapter is larger than 1/2", threads won't even fit in a 9/16" socket, just about in a 5/8, and sloppy in an 11/16" ''

16ulc3O.jpg

Iron pipe actual sizes.

That would seem to indicate the adapter is 3/8'' pipe thread. probably a simple 3/8'' X 1/4'' reducer bushing.

S5GYA1q.jpg
 
(quoted from post at 09:57:44 08/11/22)
''the adapter is larger than 1/2", threads won't even fit in a 9/16" socket, just about in a 5/8, and sloppy in an 11/16" ''

16ulc3O.jpg

Iron pipe actual sizes.

That would seem to indicate the adapter is 3/8'' pipe thread. probably a simple 3/8'' X 1/4'' reducer bushing.

S5GYA1q.jpg

I was referring to the O.D. of the outer threads on the bushing, ~5/8". The threads on the plug are ~1/2". The bushing nearly threads into a 5/8" coarse thread nut, the plug into a 1/2" coase thread nut.

I need to get pictures next time its out.
 

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