The 'octopus' is supposed to self-center with help from the internal springs when in use with a normally working brake system. When all parts are fine, you don't have to perform any kind of manual reset or special procedure after a brake job (in oppose to the 140/160 part which will and should lock in light on position).

Unfortunately, however, it clogs up over time. This may cause the piston to stick in one end position when pressure differences appear after a brake job or failure. Sometimes disassembling and cleaning will fix the problem, sometimes not.

Martin
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'65 121, '73 165