CY spring replacement repair for SEKISUIWEST ​​GFA52

"The door lever is broken and I want to repair it."

WESTSEKISUI version. (WEST171 lever handle entrance lock full set)

Tiny ohagi type thumbturn type. (Cylinder for GFA52 or 5200)

When disassembled, the spring is completely broken. It's been about 30 years.

There was no thick spring, but a long one was used instead.Is it a little weak? (Do you procure thick ones?)

Replacement lock case C55However, because the current product is compact, the front BP does not fit.Therefore, when replacing it, inform that additional work is required and end it.