Some caliper boots have metal built inside of the rubber lip to hold them to the caliper so they have no exterior separate spring.

Centric sells caliper rebuilds kits with the small O-ring seal if you split the calipers. If you split the calipers look up the torque for the bolts before you split them.

For some reason most kits don't have heat shields for the reads on ATE calipers.

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84 300D, 82 Volvo 244Gl Diesel