Stuck spool tension cap

[tincanary]

I got a couple of older (early/mid 80s) 5500Cs in for service and they were both used heavily in saltwater.  I got both apart but one of them has a seized spool tension knob.  I can't get to the crank side spool bearing until I take that cap off.  Would it be safe to assume that the cap is "salted" on?  If so, should I run it through vinegar in my ultrasonic cleaner?

EDIT:  I should mention that I also tried Channel Locks but it made the whole threaded insert for the tension knob rotate.  She's salted on there good.

[oc1]

I think that once that insert moves then you're done for.  Good bye side plate. The insert is harder metal so moving it will just ream out the softer side plate.  Peening it back probably won't work and you can't really give it a good whack without removing the end cap first.  Soaking the end cap is not likely to make it so loose that the insert will not move again.  Cutting off the end cap with an abrasive dick would be difficult because the threads are so small.

You could try cleaning the bearing in situ with solvent and then oil.  Wedge a piece of wood skewer or dowel into the bearing and spin it with a drill motor.
-steve

[tincanary]

The insert doesn't spin freely without the aid of a big pair of Channel Locks.  I had no idea it was rotating until I thought "hey, why isn't this cap backing off?" and watched it from the other side.  I'll give her a vinegar bath and try again.

[alantani]

if there is no plastic to melt, then torching it might be your best option.