[xj] Fuel level transmitter repair

I finally got the transmitters out of the tanks. Both were stuck in one
position, and both floats were a bit short of 1/4 filled with fuel.

A quick search didn’t reveal anybody elses experiences (except for drilling
a hole in the float). A short reflection on the fact that these cars and
their components came from a day when ‘things’ could be worked on gave me
the courage to begin.

The second thing to do is unsnap the float from the arm. There are two ways
to put it back, and the most reasonable-looking way is wrong. So the first
thing to do is make a sketch.

The solvents I tried wouldn’t free-up the arm. Should have tried
carburettor cleaner, but it was out of reach. Some persistant wiggling of
the arm, aided with a little twist with a screwdriver on the slotted stub
that sticks out of the housing got the arm moving again. Checked the
resistance at all positions and found nothing but open-circuit.

I opened the housing and found the resistance wire and slider to be in fine
shape. The problem was that the pivot point of the arm is also an
electrical contact, and this area was crudded-up with residue from the
fuel. I gave the area a quick dressing with a Dremel MotoTool, then, using
a jewelers loupe, chipped off with a knife the stuff that was still
clinging. One more dressing with the Dremel, followed by polishing with a
stick-shaped eraser trimmed down to enter the bearing area in the housing
and other spots finished the job. Looks good, and the resistance
measurements seem reasonable.

I am toying with the idea of soldering in a piece of braided wire to bypass
this pivot contact. Not sure if solder will stick to the arm.

Back to the fuel-logged floats. I didn’t like the idea of punching a hole
in them. If the fuel got in by itself, it can get out the same way. Four
semesters of physical chemistry is now going to pay off. Drop the fuel
vapor pressure outside the float by removing it from the fuel tank.
Increase the vapor pressure inside the float by putting it on the dash of a
non-Jag car in the New Mexico sunshine (Protected from direct sun: UV
degradation). I have been weighing the floats every few hours, and the
change is dramatic.

Any recommendations for a coating to reduce the tendency of fuel to enter
the float?

A final note on the transmitter housing. There is a delicate wire inside,
standing tall, beckoning you to break it. Don’t.

Gene McGough
XJ6C 1976
XK-150 1957===================================================
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A final note on the transmitter housing. There is a delicate wire inside,
standing tall, beckoning you to break it. Don’t.

I’m currently working on a project for an astonomical detector system. This
has two extremely highly specified cooled CCD arrays in, each 4000x2000
pixels. The 40 bond wires are exposed, made of gold, and only 20um thick.
The arrays cost $150k each. Under those circumstances you badly want to
keep track of exactly where all ten of your fingers are at any one time!

Craig===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/xjfaq.html
Archives: http://www.jag-lovers.org/lists/search.html

To remove yourself from this list, go to http://www.jag-lovers.org/cgi-bin/majordomo.

I’m currently working on a project for an astonomical detector system.
This
has two extremely highly specified cooled CCD arrays in, each 4000x2000
pixels. The 40 bond wires are exposed, made of gold, and only 20um thick.
The arrays cost $150k each. Under those circumstances you badly want to
keep track of exactly where all ten of your fingers are at any one time!

Craig

Yes, and also:
Anyone less than 150 years old,
Or,
having more than, or less than… two feet,
Or,
endowed with wings, should be locked out of the room.

TEE-HEE!!!

Charlie
Lumps Admin.
Customized 83 XJ6 /350/700R4/From: “Craig Sawyers” wrote:
Subject: RE: [xj] Fuel level transmitter repair

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/xjfaq.html
Archives: http://www.jag-lovers.org/lists/search.html

To remove yourself from this list, go to http://www.jag-lovers.org/cgi-bin/majordomo.