IH 966 Drain Plug Crossthreaded

[Bootheal]

Not sure how it happened but it did so what is the fix. I thought I could chase the threads with a tap and be ok but now there's an oil drip from the plug. I didn't replace the crush washer but never have in the past.

Could I silver solder the threads and cut them again?

Thanks

 

[Ronsii]

Usually the threads do NOT seal on drain plugs, the only sealing surface is the crush washer whether it be nylon,copper or something else... in fact the manufactures always say to replace crush washers whenever the plug is R&R'd. Is there a chance you chased the threads off angle to the original bore??? what kind of tap did you use? size,class, and type?

 

[kshansen]

Agree with Ronsii, why not try replacing the crush washer? That is why they use them to seal the plug to the oil pan, assuming it is the oil pan plug you are talking about.

 

[Ronsii]

I should have added.... I have seen drain plugs with pipe plug threads on some equipment.... but they never have provisions for a washer

 

[Bootheal]

I thought the crush washer was just a backup.

The tap I believe was a 7/8 - 14. I will check this tomorrow. Came by the tap size from the new drain plug (didn't have a new washer available at the time). I do have a new washer waiting until I drop the oil.

 

[Ronsii]

7/8-14 is a straight/parallel thread not a taper thread like pipe threads use so they become tighter as you thread them in to seal.

 

[Bootheal]

So, were the original threads taper or straight?
IH parts sheet didn't indicate it was pipe thread.

 

[Ronsii]

I don't think you can find an off the shelf 7/8-14 tap in pipe taper...

 

[Bootheal]

So you think the tap should have been a taper?

 

[Ronsii]

No sorry , I guess I should have been more clear in my answer.... there is no 7/8-14 thread made that has pipe taper. You would have to cut one yourself or have a machinist make one special for you. 7/8-14 is a straight thread designed for fasteners not sealing that is why there is a flange for the sealing washer on the plug.

 

[Jonas302]

Sometimes in a tough situation its better to find a softer washer to seal better and possibly squish into some misalignment than a copper or metal one

 

[Delmer]

7/8 x14 threads won't even notice if the washer is copper or aluminum. I wouldn't put a plastic washer in there, or use an o-ring anywhere there isn't a space for an o ring. If it's copper, then it's work hardened and you should get a new one, or anneal the old one. If it's aluminum then it's squished too flat and distorted, so get a new one.

 

[Bootheal]

New washer is in the toolbox. Would be great if that would be the fix. Thanks to all for taking the time to to comment. I think I know a little bit and then I find out I don't know much at all!

 

[motoOzarks]

howdy neighbor
you can buy expandable drain plug replacements or plugs that kinda cut their own threads
not sure where in order to get your size
I agree with putting a washer under it

 

[repowerguy]

If you hook your shop vac up to the suck bucket and it to the blow by tube, you may be able to do the quick switcheroo of the crush washer.
The vacuum should hold the oil in the pan with only a small amount lost.

 

[Bootheal]

Howdy back at you motoOzarks! I'm west of Tilsit couple of miles.

Repowerguy - that is a great idea and time to try it out this weekend. Been running with the drip but it's aggravating.

Thanks to both for taking time to offer assistance. Let you know how it goes.

 

[tool_king]

Not sure how it happened but it did so what is the fix. I thought I could chase the threads with a tap and be ok but now there's an oil drip from the plug. I didn't replace the crush washer but never have in the past.

Could I silver solder the threads and cut them again?

Thanks

I have good luck with using a metal/rubber washer that comes with air filters .You can get them in different sizes and they are beveled a bit so it will crush down .Never had a problem with a leak from them .

 

[Bootheal]

I have been at other things and not tried the suck bucket yet so I may look for some type of washer like this. Thank you.

 

[tool_king]

I have been at other things and not tried the suck bucket yet so I may look for some type of washer like this. Thank you.

The size you be looking for would be used on large air compressors like Sullair 75o and larger .They called bonded washers .I have them around here ,If I find it I can send you one .

 

[Ronsii]

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