Fuel tank cap

Hey guys, could anyone help me track down the part number for the fuel cap and filler neck on a D5H 1DD6574? The tank has a light alloy fitting attached to the neck where the cap seats and screws on. I can't find a part number for the whole assembly, so a replacement would work just fine. Thanks.

Anyone?

I'm finding two different tank groups for this. One uses tank group 9N4213 with cap 7X-7700, and the other is tank group 3A8546 with cap 7T-2036. Tank group 3A8546 also uses a fuel strainer, part number 9P-7121. The filler neck isn't available separately—it's integrated into the tank itself.

Found a supplier doing 3" Filler Neck - Oil Tank Weld On Billet Cap for rail locomotives, marine, racing vehicles, liquid processing, storage, off-road, construction, mining, farm and forestry equipment. No personal experience with them though.

Can you post a photo of the filler neck setup on your dozer?

My tractor has the 7T-2036, but the problem is that not just the cap itself is damaged—the part where the cap screws in is also damaged. Both pieces are made of light alloy metal. I've got the 7T-2036 number, but I really need to find the part number for the neck piece. Any compatible system would work as long as I can track down that neck part number.

Looking at the parts breakdown for your tank assembly, the neck with the screw thread where the cap sits is actually part of the fuel tank itself and isn't available as a separate component.

This diagram might give you a better view of the cap and fittings.

Looks like I'll need to find the parts somewhere else. Since both the cap and filler neck are shot, just getting a replacement cap won't cut it. Thanks for the help anyway.

If you measure the filler neck, you might discover it matches a standard pipe diameter and wall thickness. Once you identify the material, any decent machine shop can thread it for you. From there, it's just a question of cutting off the old neck and welding a new one on.

On my old Mack truck tanks, I shaved off the first 3 or 4 threads to let the screw-on cap thread on properly. After 30 years of fueling, those threads wear down quite a bit.

Not shaved, just cut back about 3/16".

What strikes me about this setup is that the cap threads onto a light alloy fixture rather than directly to the fuel neck itself. It's like there's an extension made of light alloy attached there, and you can tell it's genuine CAT. I'm curious how they actually integrated this as part of the tank assembly. I don't have threads I can shave off, so I need to figure out how this all comes together.

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I found a Cat fuel cap, part number 7x7700, that should work as a replacement.