Collets as well as router bits are consumable items. When worn, you need to replace them.
Sadly, the 5362 appears to be no longer supported either by Porter Cable (or whoever owns them this week), or by the aftermarket replacement parts companies.
If you could find a NEW replacement collet for under $50.00, I'd consider that a win, especially if you like the router. If all you can find are used parts ... it is time to consider a new router.
The danger of worn collets is that the router bit will slip during cuts. I've had this happen on both my PC routers and my Makita plunge router and recently repaired my bench top due to the Makita deciding to cut through the work, the backing board, AND the bench rather quickly. I heard the motor loading down, and eased off the cut, but the router bit (an upcut spirial bit btw) went quickly into the bench top (grrrrrr).
My solution is to buy replacement collets, and always have a new one on hand. When a bit slips, both the bit and the collet are tossed, as I don't have time or interest in gambling on what really is an inexpensive consumable.
I've always disliked that collet and I've still got a couple of routers that use it.
Delta used that collet in their router collet insert for their HD shapers. Apparently they also had slippage problems so they felt compelled to issue the below service bulletin. While this solution may or may not work, I think its worth a try. It worked for me. I'm still vigilant about romping down on the wrenches.
I've noted that problem too when using upcutters. The cutting action tends to pull the bit out of the collet I suppose. Aside from having one walk out of the collet and nearly ruining a mortise, it's a bit rough on the collet too (see below). That's out of a Dewalt router.
The service bulletin makes a lot of sense - will try that and/or go to straight bits instead since they should be less inclined to walk out of the collet.