sump plug

[Arnie]

Hi,,
Hoping someone here can point me in the right direction.
I have decided to change the oils in my Fordson super major, i tried to remove the sump nut but it had been rounded off and tightened by a chisel and hamer, I did get it out with mole grips and placed an order for a new one.
When it arrived it looked different to the picture and was different to the one iemoved, mine was a very fine thread and measured 18.6mm across the thread (diameter) the new one measured 21.4mm across the thread and had a course thread, so it was very different, i contacted the supplier who was helpful eventually and sent a new one to me, i excitedly opened the package to find this one was even bigger and had a larger head, after talking to the supplier they seem to think i do not have a fordson super major as all of the sump bolts are a standard size.
What i need to know is are they correct and mine is not a major, or has it been bodged to effect a repair sometime.
Does anyone know if this is a standard bolt and if one can be purchased from anywhere, what is the size and thread type. I have welded a nut to the top so i can put it back in for now so i can top my fields, but i really would like to replace it if possible.
Thanks in advance for any help you might be able to offer,

[Billy26F5]

You do have the original one fitted, there are no replacements available, so you'll need to find a good second hand one; I would stick with the current one for now and leave it until at least the next oil change. The Major sump plug is not a normal one because of the fine thread and it uses a copper washer rather than tapered thread to seal. The thread will not be metric.
Sandy

[Arnie]

Thank you Billy,
Do you know where i can get one from, or does anyone have one for sale on here, iys beedriving me mad, thanks for resolving it for me.
thanks again.

[Emiel]

Hi,

Think you need this one;

https://histoparts.com/engine-oil-sump- ... inch-unf/3

Fitted one some time ago from this supplier if I remember correctly. And it was a direct replacement.

Rgds

[Billy26F5]

I'm not very sure, as it mentions Dexta's and Dexta drain plugs are very different from Major drain plugs. It could be that the company have changed something though.
Sandy

[Emiel]

The dexta is a mistake I think. Our dexta has a smaller plug if I remember correctly.

Checked the part no for the major. The early ones up to 57/4 had a plug e1adkn 6731. The post 57/4 tractors had a plug en-6730.

Can’t find a reference to the size but 7/8-unf makes sense for me.

You can eventually weld a nut onto the old plug. That is a good farm fix imho.

[Emiel]

The dexta is a mistake I think. Our dexta has a smaller plug if I remember correctly.

Checked the part no for the major. The early ones up to 57/4 had a plug e1adkn 6731. The post 57/4 tractors had a plug en-6730.

Can’t find a reference to the size but 7/8-unf makes sense for me.

You can eventually weld a nut onto the old plug. That is a good farm fix imho.

[Arnie]

Thanks for the reply guys but 7/8 will definitely not fit I have two of those already, mine measures 3/4 or 18.6mm.
Thanks for taking the time to post though.

[Emiel]

Allright. Then the newer type is 3/4. Might be the same a a later ford tractor. It should then be available at the nh tractor dealer.

[Billy26F5]

I'm not sure if it's UNF or BSF, it's closest to 3/4" (19.05mm), but all the measurements I've found give the OD of the thread as the nominal diameter. Unfortunately I can't measure any of our plugs. The early plug is E1ADKN-6730A, E1ADKN-6731 is the Fram oil filter element.
Sandy

[Arnie]

Thanks both I will use those codes to see if I can locate one, as I am in Wales I struggle to find anywhere I can take it to compare.

Thanks again

[John b]

Arnie, i should have a couple of old sump plugs kicking around. Are you far from Hereford?

[Arnie]

Hi John,

Thanks for your reply I am in Aberystwyth, could you post via Hermes if I pay the postage.

Nick.

[John b]

Hi Nick, this is the sump plug from a super major. The older ones were larger with (i think) a UNF thread, this one has a finer thread, not sure what it is. The head is a bit chewed but it's still usable. For reference it's the same plug used in the Ford D series Cargo lorry engines, not sure if they are still available new

[Billy26F5]

The older plug was 7/8"UNF, the later plug thread is unidentfied at the moment (not BSF, UNF, UNEF ISOF nor even BSP or NPT). What does the calliper come up with in inches?
That plug needs a bit of a clean!
Sandy

[John b]

19.05mm is 3/4". I wire brushed it up, the threads are ok but it could do with a bit of emery cloth on it

[John b]

My pitch gauge says the thread is 24tpi, American National Screw Thread maybe?

[Emiel]

3/4-24 uns may be?

[John b]

Could be, 24 tpi is a whitworth thread but only up to 7/32

[Billy26F5]

American National fine threads are like UNF in pitch and diameter, so it can't be that. What I'm puzzled by is that the diameter doesn't coincide with any of the usual ones (it is indeed close to 3/4" but it's not quite that), 24 tpi does suggest an inch based thread (as you would expect) but it's very fine compared to the BSF threads that I thought this might be (having already seen it wasn't UNF or UNEF). I'll need to look at the repair manual to see if there's any comment on this. Maybe Ford made this thread specifically for these drain plugs!
Sandy

[John b]

I think Emiel may be correct about it being a UNS thread
https://www.gaugestools.com/34-24-uns-t ... -lead-tap/

[Billy26F5]

It does look like it, but I still can't think why the diameter is slightly less than 3/4". It could be to make the plug looser and easier to remove, but the thought of not having all the thread working makes it seem easier to damage if the copper washer is reluctant to seal well.
Sandy

[Emiel]

3/4-24 uns should be a nominal diameter of 0.7416” to 07488”. In millimeters that is between 18.83 and 19.01 mm.

Never heard of uns thread before. The measured diameter is a bit lower but to its not a new plug nor do I know the accuracy of the calliper.

[Billy26F5]

That explains it, I thought the nominal diameter would be exactly 3/4" as with Whitworth and Unified threads but the slightly smaller sizes for the 3/4-24 UNS definitely fits with the wear these plugs will have (in 10000 hours there are 50 oil changes, not forgetting an extra two or three for running in) to get the measurements John and Nick have. Good to know there's a tap for a damaged sump.
Sandy

[John b]

Given the age of these machines now and the odd thread size there is almost a case for drilling and tapping the centre of the sump plug to take a smaller UNF bolt and using Loctite to fix the old plug permanently in place