Dexta fuel tap/valve

I am seeing a slow leak at the fuel tap on the bottom of the tank. This is a diesel tractor. When I pull the tap/valve, what kind of thread will I find. I assume it is British, but will it be the straight thread with a separate sealing surface, or a tapered thread like our Pipe thread?

Many thanks

David

Hi David:

I do not have a dexter, but have worked on English MF 135's, and the Fuel shut off tap you speak about on the MF's is a straight thread, no taper.

On the Masseys I made a leather washer to seal and plumbers tape on the threads, and they have not leaked since reinstalled many years ago.

The Dexta seems to be very similar to the MF's but I could be wrong as to Fuel Tap set up.

Hope this helps.

Kenneth Armour

Thanks; your experience sounds like a good place for me to start. I've had success sealing both straight and tapered threads with pipe tape and pipe sealer in a tube, but it takes the good sealer to stand up to fuel.

This is not a fun job to look forward to, and my best excuse to wait is that it's not too bad. So knowing it is going to be straight forward repair will help me get started.

David

One more question; I found the leak, it is where the 1/4 inch metal line is connected to the valve. That line is a copper line that is obviously a replacement. I see an original steel line from the pump to the filter has a wedding ring type of compression fitting. That would be what I need to repair the line from the valve on the tank. What are these compression fittings called? The compression fitting/ring at the filter is steel unit. Where to get them, and are there alternate parts that work? copper?

Thanks
David

Hi:

The line from the pump to the tank, on the MF'135, is a flare type (something like a brake line going to the brake cylinder)

Sorry but I have not had to mess with the lines as I have not had leaks where teh line screws into the tap on the tank.

I would assume you can get compression fittings at NAPA.

I would go with all steel, or all copper, as mixing metals can sometimes lead to trouble.

But I have seen copper compression fittings on steel lines, so I guess it may not be a problem.

Kenneth Armour

If it were me. I would take the old line into somewhere like NAPA, or a diesel engine supplier, so they know exactly what you are looking for.

I have found taking the old part in, makes life simple, with no mistakes.

I am assuming you can get a new line professionally made for a reasonable fee, which may be the best solution.

Kenneth Armour

Thanks Kenneth. I appreciate the note about the use of similar metals to avoid the corrosion issue. Last night while doing a little research, on the net, I found that the threaded nut that screws into the pump and tank valve is identical to the nut used on brake lines on a large number of US cars. That will make it easy to source new materials. The cross use of standards from British design to USA design makes this puzzle more interesting.

I'll post when I get more info.

David

Hi David:

That is great the nuts are common.

Yep the British always made things interesting.

I have a Series Land Rover so I know where you are coming from.

Good luck and let us know how you make out.

Kenneth

Is this the FUEL TAP?
Bob...

The fuel tap/valve on the tractor is also the hand pump to feed fuel into the intake manifold for preheating. So that one is not the same as what is currently on the tractor.

David

My Dexta fuel project has been on hold. We raise about 400 dahlias and it was harvest time. We got the dahlias dug out and stored in the shed for now, so I had another chance to work on the tractor.
I installed the new pump, which is an exact replacement for the OEM mechanical pump. That feeds from the tank to the filter, which I also replaced. The lines to and from the filter were good and looked like OEM. The line from the tank tap was copper and obviously hand bent and too long. I made a new steel line, but the question I had about fittings was driven by the ports on the fuel pump and tank tap. Those ports are inward facing cones with internal threads to accept the tubing nuts. It would seem that compression, (olive), fittings would be what as intended, as that is what is on the steel lines to the filter. I had trouble finding tube nuts that reached deep enough to compress the olive. I had to use small washers to bridge the gap between the tubing nuts and the compression/olive fittings. It seems to work great. So I'm back in the field.
Thanks for the help, but I do have on more question. Is it possible that the OEM fittings were the "bubble" type that is used on British brakes?

David in Washington state, USA

I might have answered my own question. At the Official New Holland Online Parts site, http://partstore.agriculture.newholland.com/us/parts-search.html#epc::mr55997ag12411
I found the picture of the fuel tap that John Deere D sent, and pictures of the "ferrule" on the fuel line. That makes it seem the ferrule/compression/olive is the original sealing method. The original nuts probably have the added length to create the seal.
David

The ferrule on the Majors ( and I'm assuming the Dexta's) are slightly more bulbous than the ones sold here in the US. I get mine from across the pond, my preference being Dunlop tractor spares in Ireland. they probably have the entire line available as well. Or you could have someone with a lathe make a few.

Pat

Thanks, actually, I'd like to get my own lathe. The trouble I could find then!

David

One more observation on sealing the fuel lines. I find Agriline has rubber washers listed for fuel pipe washers. It looks like very short sections of fuel line that would be used instead of olives.

Does anyone have experience with these. It looks like they would be easy to make with a sharp knife.

David