Ultimaker 3 feeder spring

[paulsroom 2]

Does anyone know what the spring specifications are for the compression spring in the feeder unit at the back of the machine?  And what are the details to order the specific one from a spring manufacturer?  I had to disassemble the feeder unit for print core 1 because the wheels inside the feeder had crunched up the filament and was actually grinding it into powder.  I discovered this when the filament got thoroughly stuck and would not unload.  Unfortunately, although usually being very careful to put all the parts in a little container, the spring shot out and is somewhere in the room.  At least I know it is in the room, but as a back-up I'd like to get a replacement spring if possible.

I have concluded that the PLA filament I used was wet and so am drying it out by packing it in silica gel - my next option is to buy a food dehydrator and use that to dry out the filament.  But first I need a complete feeder assembly.  

[paulsroom 2]

From various investigations, I believe that the current specifications of the feeder spring are

• Outside diameter: 7.5mm

• Inside diameter: 5mm

• String diameter: 1.2mm

• Height: 20mm

But I believe that there has also been a slightly weaker spring fitted to UM2 at some point

• Outside diameter: 7.5mm

• Inside diameter: 4.5mm

• String diameter: 1.2mm

• Height: 16mm

Would this weaker spring still work okay and lessen the occurrence of filament getting stuck in the feeder?