type of bolts used on a Mk2 fuel sender
 

Hi folks,'
In the process of opening up two original gas tanks on a Mk2. Luckily, they are sound and no rust through.

There is an AMAZING amount of crap in the tanks though so I intend to take them to a tank shop to be opened, cleaned, and sealed with Red-Kote.

In taking the fuel level sending units and the pickup tubes out, I had some screw casualties. snapped the heads, Some I have been able to grab and remove after the unit was removed, but I still need to drill out a couple and retap.

Question is what thread is supposed to be there? SAE? or BA?

Maybe the bigger question is a rule of thumb for what used BS threads and when did they keep the SAE?

I had generally assumed that engine and tranny parts were SAE and everything else was BSF/BSW or BA.

Hi Jim
I have always used 10/32 on the sender units
and have never had a problem but I have never really checked them either
I have probably done 20 plus tanks
Just center punch and use a small center drill then drill number 21 drill
(real careful )
Lots of Luck

If I have read the parts book book correctly (1941 MkI*book), they should be 2BA.
Although the MkII* is later, I think they would have stuck with the same threads. I don't actually know.
The following might help?
2BA is not the same as 10-32 but it is sort of close.
2BA is about 0.182 dia. (these are actual measurements on screws, not from a reference book)
10-32 is about 0.189 dia.
Over about 4 threads one will NEARLY lay into the other
Reality is they don't fit and I can imagine that what probably happens is that they go tight in the thread before the head takes up any real clamping load.(this will depend on how good a condition the thread is in)
If you can't locate the 2BA screws then maybe tapping to 10-32 is an answer.
Keep in mind that the screws go into a blind hole in most tanks, so a plug (bottom) tap is in order.
The holes are blind because the mounting ring is welded to the top of the tank after the ring is made.

My Illustrated Parts Catalogue, FUC-03, Carrier Universal MkI* and MkII* 1941-4 by Ford Canada page 199 and illustration no. 38 shows under Gauge - tank unit:

P/N 27068 S2, Screw - #10-32 x 5/8" round head, quantity 6 on the Welsh Guard Models only.

It also has an obscure note under the heading "Interchangeable Proprietary or M.T. Part Number" NA/AN44222.

George

And on page 204 it says it again for the fuel sender screws,10-32, but then it also says for the "Cap and tube outlet", Screw # 2BA x 3/8 round head qty 4.

Isn't that Irish, to have two different, but visibly indistinguishable standards melded together in one fuel tank.

How stupid of me to think they would be the same!

It must of been engineered by two different engineers :doh:

no matter what size, the 10 /32 will work, as by the time the thread is cleaned with a 10/32 tap the screw will have enough pull to hold and seal
But that is just my opinion /millwright for the last 50yrars/Fixer of engineers mistakes :devil:

Agreed: the filler neck is original British, so would be British threads. The sending unit flange is a Cdn design, so would be North American threads. Makes perfect sense.

Same here....
 

We have used 10/32 on many tanks with good sealing and no thread issues.

As the British design only used dipsticks in petrol tanks, the addition of the sender units in the Canadian design, would obviously use hardware and tooling that they had to hand in their country. As much as possible was kept interchangeable.
I have come across differences in the axle pinion shafts though, the threaded hole in the end of the pinion shaft, I have found with both NF and NC threads, anyone come across that?

Richard, the tooling was in use in Canada for the making of the previous 40, 000+? (number unknown to me) carrier fuel tanks, without senders.

The fuel tank sender, and the fuel pick up both have a Ford of Canada part number.
The pick up mounting ring has a TL (Brit?) part number. Maybe this is the problem. (they too would have been made by Ford of Canada)

On the Pinions, yes I have seen both. The fine thread seems more logical to me. I have wondered if the difference was the origin. Brit, Can. or US?
The small pinion bearing was different between U.K. and Can. production.

I just got in new sender units from Macs' Auto. Comes with new screws and gaskets. So, looks like the bit of drilling and re-tapping will be in SAE.

The Fuel pick-up uses BA then? OK, I have taps for that...

Thanks everyone for responding!

Oh, while I didn't find the extension for the distributor, I did find one in the box of spare distributor parts that came with the carrier. Will be putting it allon this weekend.

Also got in a new Fuel pump so I may already be prepared for a dead fuel pump gasket from sitting so long.

I did a pretty good search under the engine with hands and a reach magnet, with no luck, I had just vaccumed the inside of the hull pretty thoroughly only a few days before this.

A few nuts and bolts and two live .38 S&W bullets with bad primers!

Oh, a rebuild plate on the front right side of the engine says it was rebuilt in 48. More details to follow for those that are interested!

Again, everyone! Thanks for your help!!

Jim, Make sure the adapter isn't sitting down beside the crankshaft gear. It must have gone somewhere. :doh:

Hopefully some more stuff will be found in the hull :)