It depends on where the shoe anchor pin and the threaded star adjustment rod is located. If the shoe anchor is located at the top of the backing plate with the adjustment rod at the bottom between the two shoes than it is duo-servo. If the adjustment rod is located at the top between the two shoes and the anchor pin is at the bottom of the backing plate then it is a leading/trailing type drum brake system.
Cables frozen? Return spring inside brake drum broken?
Not sure what you are talking about. If you are referring to a part in the engine then the piston does not have a return spring. If you are referring to the piston, not quit the right term, in the brake area then in the wheels the there is a spring and in the actuator there is a spring. No other item I have ever heard of as a piston return spring. Can you elaborate?
Possibly nothing more than the brake pedal return spring catching on something.
bad brake line, weak return spring, bad caliper or wheel cyl.
Drum brake? Broken return spring? Bad self-adjuster? Parking brake not adjusted properly? Disc Brake? Frozen caliper? Parking brake not adjusted properly?
Broken/ disconnected return spring? Worn brake pad? Loose caliper?
Here are the list of Drum Brake Parts: Bleeder Screw Cap Bleeder Screw Wheel Cylinder Cup Wheel Cylinder Boot Wheel Cylinder Wheel Cylinder Piston Shoe to Shoe Spring Strut Strut to Shoe Spring Parking Lever Leading Shoe and Lining Anchor Retainer Pin Trailing Brake Shoe Shoe Hold Down Spring Shoe Return Spring Latch Adjusting Lever Stopper Spring Pin Brake Drum
Here are the list of Drum Brake Parts: Bleeder Screw Cap Bleeder Screw Wheel Cylinder Cup Wheel Cylinder Boot Wheel Cylinder Wheel Cylinder Piston Shoe to Shoe Spring Strut Strut to Shoe Spring Parking Lever Leading Shoe and Lining Anchor Retainer Pin Trailing Brake Shoe Shoe Hold Down Spring Shoe Return Spring Latch Adjusting Lever Stopper Spring Pin Brake Drum
Frozen brake calipers? Broken return spring in rear drums? Frozen emergency brake cable? Bad master cylinder (return plugged)? Maladjusted master cylinder clevis pin?
Bad tire? Bad Wheel bearing? Broken return spring in brake drum if so equipped?
A brake spring tool is used for the removal and replacment of springs utilized in drum brake assemblies.
A brake spring pliers is a huge help.A brake spring pliers is a huge help.