On the Ampicos I have rebuilt, I used my bench knife to ever-so-gently
create a lengthwise cut into each lead section on each nipple,  and use
a screwdriver to slightly "enlarge" it,  then slip it off.  Care must
be taken not to cut the lead deeper than its own wall thickness, to
avoid scarring the brass nipples.  This was done only if any of the
lead tubing was showing signs of decomposition or leakage.

Pulling the lead tubing from the brass nipples sometimes will result
in a damaged tracker bar, the brass nipple yielding to the force.
I generally replace lead tubing with lead tubing,  but if you want
to use rubber,  brass elbows must be used to simulate the lead tubing
turns.

The rubber tubing is carefully laid to duplicate the same paths as the
original lead,  using strips of pump cloth fastened at on end (looped)
with a tack to gather the tubing.

I have rebuilt professionally since 1972,  and still don't consider
myself an expert, so I would welcome any expert's advice on how to
better accomplish this task.

S. K. Goodman