I have a hybrid (18+ years old) that I use for daily commuting which has developed a problem with the cranks. Every so often (perhaps 10% of the time) when I push down on either crank arm after free-wheeling, there is the sound of the cranks snagging/grinding on something internally, which can sometimes be felt through the pedals. The cranks then momentarily lose resistance and stop driving. This usually corrects itself within another complete 1-2 revolutions of the cranks (leading to further sounds of grinding metal), after which resistance is restored.

I'm not sure whether it's relevant but I recently had the pedals replaced on the bike, and the mechanic mentioned they were hard to remove. The cranks seemed to be fine before having the pedals replaced (no problems or noises). The bike also used to make a quiet "tick-tick-tick" sound when free-wheeled, but I've noticed this has stopped completely.

I suspect the bottom bracket needs replacing (the last time would be years ago, if ever), and we've had lots of rain recently so maybe some water found its way in. Everything else (chain, gears, pedals, etc.) are fine.

Are these symptoms consistent with bottom bracket failure, or something else? Does this explain why the "tick-tick-tick" sound has stopped?

Thanks.