Rounded off drain plug

[Dave M7040]

If the drain plug has a sealing washer between the plug and the place where it threads in , it will have a straight thread not a tapered thread like plumbing fitting so be very careful with what you put back because if you now damage the threads with the wrong plug thread you are in a really big mess.

Often the straight threaded plugs, especially likely if your Ford has any British connection, will be using a Whitworth thread. It will appear very similar to an American fine thread on a bolt but the American National Fine thread has a 60 degree pitch where as the Whitworth thread pitch is 55 degrees.

The NF bolt will appear to be correct at the start of you screwing it in, but the more you screw it in, the bigger the conflict between the 55 degree threads and the 60 degree threads and the hole will be seriously stripped.

This link will direct you to a description of the many threads around and will contain more than you will want to know.; I send you to it because it will help you understand what you replace the plug with is critical.

https://www.teesing.com/files/en/brochures/Type-of-thread.pdf

If you invest some $ in having an experienced mechanic or machinist remove the old plug, now you know you have the correct thread characteristics. A new head can be welded on the old base portion of the plug and re used.

Tractor salvage yards are another possible source for your plug.

Don't turn a small job into a much bigger one requiring helicoils or inserts.

Dave M7040

 

[thepumpguysc]

Have you tried BEATING a socket on it?? The extra pounding might help break it loose..??

 

[downslope]

Assuming it is an early 4 cylinder all American made Ford 960, these did use some square head tapered pipe plugs in the housings. Hard to believe it's gotten so tight, but who knows what a previous owner/operator may have done or installed, possibly improperly.

 

[Egon]

No go with a pipe wrench, simply can't get a good grip on it.

Is the pipe wrench too big?

[video]https://www.google.ca/search?q=pipe+wrench+use&client=safari&hl=en-ca&prmd=ivsn&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiGjKnex5baAhUBUa0KHVOeA5IQ_AUIESgB&biw=1024&bih=728#imgrc=DCz-mKrBy5SS4M:[/video]

 

[Ford850]

These plugs are the square head NPT. More than likely the square head doesn't just have rounded corners, but its now a rounded tapered cone so any wrench or socket pulls away/off the head as you apply force. I'd try to grind or cut some new flat sides, or a slot like mentioned above. Otherwise a large nut tack welded to it would be my choice.

 

[pmsmechanic]

So once you get his plug out I would not replace it with a similar plug. You can get brass pipe plugs with a six sided bolt head which is what I would use. You aren't as likely to be tempted to use a vice grip or a crescent wrench since a proper sized socket will now work.

 

[Ford850]

So once you get his plug out I would not replace it with a similar plug. You can get brass pipe plugs with a six sided bolt head which is what I would use. You aren't as likely to be tempted to use a vice grip or a crescent wrench since a proper sized socket will now work.

I don't know, since the old one lasted 60 years I might stick with steel.

 

[Kando]

I'm going to talk to a small welding/repair shop down the road about removing that plug. Any attempts I make simply end up stripping it bit by bit more. There's a bar that runs underneath the tractor side to side connecting to the FEL mounting and it sits directly underneath that plug with about 1½" of space between it and the plug head.

 

[Peter 315]

Good luck, That might be the best way let us know how you make out

 

[Johnkn]

I'm going to talk to a small welding/repair shop down the road about removing that plug. Any attempts I make simply end up stripping it bit by bit more. There's a bar that runs underneath the tractor side to side connecting to the FEL mounting and it sits directly underneath that plug with about 1ｽ" of space between it and the plug head.

What ever you do don't try the bolt extractor I showed above. That will likely remove it, but then you wouldn't be able to pay the shop so that they can use their bolt extractor kit. :confused2: