May not be the whole steering but I'd get it looked at pronto. You could try jacking up the front & trying it to see if the effort reduces with no load. Disconnecting the steering u-joint will further isolate the effort problem.
Some people use chassis grease in our late-60s-english racks & the effect of that is unknown long-term. If the rack uses 90-wt gear lube as it was designed to, and a boot leaks, you WILL have metal-to-metal contact inside. Good luck-
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