If you are referring to the cross spring in the rear caliper that the retaining pins are held in place and keep the pads from rattling then ,YES. I think it keeps the pad retaining pins from falling out.
The rear brake disc is secured to the rear hub with an allen screw.

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1990 190E 2.6
1996 Grand Voyager 3.3
1985 Mustang GT 5.0 5 SPD
1982 Suzuki GS 750T