I have a Penn 49L that has caught a lot of fish. The clicker spring and clicker are just worn out. Is there an easy way to replace or rebuild this without buying the entire reel side assembly?
No, there really isn't. And new side plates are something like $30...
If you have the time and inclination you could try drilling a 1mm hole through the click spring retaining rivets (from the inside of the side plate). Use a larger drill (from the outside of the side plate) to remove the rivet heads taking care not to drill into the sideplate.
Grind off the click button riveted end (again from the inside) and remove the click tongue. Fit new click button and secure click tongue with retaining ring.
Fit new click spring and secure with machine screws etc.
Better check the price of these parts as akfish's advice may be cheaper and less troublesome in the long run.
an option might be to try to adapt the clicker assembly from the penn 113hl senator.
https://www.mysticparts.com/Assets/images/pennparts/schematics/113hl_half.pdf (https://www.mysticparts.com/Assets/images/pennparts/schematics/113hl_half.pdf)
the click tongue is #35-60, the click button is #36-113, and the retaining ring (c-clip) is #68B 600. if the shaft of the click button is too short, you might be able to file or grind away at the side plate. if it's too long, you might be able to cut a new groove in the shaft for the retaining ring or shim it somehow. alan
"Edited as per Moderators to correct Scott's Bait & Tackle over to their new store name Mystic Reel Parts / www.mysticparts.com"
Or look for another 49 on Fleabay. Look for one from the Great Lakes region as it will have minimal corrosion.
Then you have something to cannibalize and serve as a parts bin. Looks like they sell in the $20-$40 and you get lots of parts besides a side plate!