HMV back bracket issue

[Codex78]

Alright, I managed to free some time yesterday and tried to disassemble everything. I didn't manage to take the tonearm out, it's really just stuck by whatever this misplaced part is. That thing won't budge, even after being treated with WD 40.
However, I managed to slightly lift the tonearm upwards, so it "fits" better in the back bracket (it's still not fully fitted though, but at least I reduced volume losses a bit).

[Codex78]

After trying all week, I finally managed to disassemble the back bracket and tonearm completely, and I can confidently say that the part that holds those horizontal bars was indeed inserted backwards. I even managed to pull it out. However, I noticed that the spring that's supposed to push the shaft is missing, so I need to order one before reassembling all that and check if everything's back into place.
Thank you all for helping!

[JerryVan]

After trying all week, I finally managed to disassemble the back bracket and tonearm completely, and I can confidently say that the part that holds those horizontal bars was indeed inserted backwards. I even managed to pull it out. However, I noticed that the spring that's supposed to push the shaft is missing, so I need to order one before reassembling all that and check if everything's back into place.
Thank you all for helping!

Sometimes, that spring is rusted in place. I have removed it, or the last traces of it, by inserting a small hook and trying to catch one of the spring coils, then pulling it up and out. Or, maybe yours is just plain old gone, as you suspect.

[jamiegramo]

If the spring is missing you can always try the spring from a retractable ball point pen.

[Codex78]

Sorry for the late reply. I cleaned everything and reassembled the back bracket. I didn't find a suitable spring sadly, but it seems to be working perfectly even without it. My machine sounds much better now! I wonder if the spring is necessary though? In that case I'll try to find one but for now I'll let everything as it is now.
Anyway, thank you all for helping me!