Full Suspension

[DCBassman]

If the nut is turned all the way out, meaning the spring is as uncompressed as it can be, then something else is wrong if it is still not bouncy, as it were.. If there is room to adjust it, but it will not turn, again, if sprays cannot loosen it, something else is wrong, and I'm not knowledgeable further than that without seeing it.

 

[fossyant]

Those adjusting 'nuts' aren't rocket science - you'll see it move further away from the spring, or nearer (compressing the spring). If it's not turning it's seized, if it's turning and the bike isn't 'bouncing' then something else is seized - like the bearings.

TBH you are better off the rear not bouncing - just wasted effort on a bike, unless it's a proper MTB, with air rear suspension.

 

[iluvmybike]

what is the 'bob'?

'Bob' is a horrible up & down motion of the bike on each pedal stroke - as you weight each pedal in turn that pushes against the spring which wastes your energy. It gets even worse if you stand up in the pedals

 

[iluvmybike]

Those adjusting 'nuts' aren't rocket science - you'll see it move further away from the spring, or nearer (compressing the spring). If it's not turning it's seized, if it's turning and the bike isn't 'bouncing' then something else is seized - like the bearings.

TBH you are better off the rear not bouncing - just wasted effort on a bike, unless it's a proper MTB, with air rear suspension.

There are no bearings in those frames or shock - just plastic bushes

 

[Spiderweb]

This is a better picture, wind the silver knurled ring further out towards the front of the bike, it will decompress the spring making it move more easily. As said previously WD40 the thread may make it easier to move, if you are finding it hard to grip then rubber coated gloves would help.
I do think that if there is no movement at all then something, maybe a pivot, has seized.