Spinning and clicking, changing speeds, or just clicking?
.. might take it out, and flick/rotate it on the axis at power up, if it's not spinning. Might be "stiction".
You'll have to undo ribbon cables so you can reach stuff, and handle it. Pull the power cable from the drive, turn on the Mac, let it sit at the blinking folder screen, stick the power cable in and rotate the drive briskly about the axis.
If it's spinning up/down and not coming ready, i've had good results with pulling/sticking in the power cable at the right interval to keep the drive spinning. Right past the clicking when it would spin down, I pull the power and apply it again. Eventually I'd find that the drive would no spin down and stay in the "ready" state. Then I gingerly put the 50 pin cable in and set the drive down.
The spinup/down thing I'd usually do with an external power supply. Though I've got one here modified with an SPDT switch in-line on the power, to make it smoother/faster.
..and then there's "freeze the drive". I've put them in a double walled ziplock bag and set them in the freezer for a while. Usually overnight or a whole day worth. Then applying the power flicking bit makes them stay if they don't just spin up right away after that.
.. and there's some out there that are probably cringing at this. To each his own.
In my experience, based on tales I'v heard, things that have been brought to me for aid.. the most common places for drives to fail is "on the shelf", followed by, "at startup".
Rarely do they seem to fail in use.
Copy your stuff any chance you get.