Sekkaku Cheat Wo Moratte Isekai Ni Teni Shita N Dakara, Suki Na You Ni Ikitemitai - Vol. 4 Ch. 23

[MangaDex]

 

[Xeroxcopy4free]

the old mecha is perfect for him then since the armour and mecha frame(main body) are separate so no pain received unlike in the new mecha used in academy both armor and frame are merged for easy repair.