Need help fixing a toilet seat!

[OM2]

I have 2 toilet seats that have stopped working
They both have a nice slow motion when put down
The mechanism that controls this seems to have broken some how and I'm scratching my head how to fix

I steam washed the area and took the seat off
There are 2 bits that do the slow motion action
On of them seems to be weak and I can twist with my hand
The other is really stiff and I can't move with my hand
I'm guessing the weak first one is the fault one

See below for a pic I took:

The one on the right is the weak one

Any idea how to fix or replace?
Can I get the part on ebay? If so, what's it called?

Thanks


OM

 

[foxhole]

New toilet seat.