Did the piston (Labeled H) pop out or the seal (E)?
The slave cylinder (I) is pressurized when the brake pedal is pushed down. The pressure moves the piston, the piston moves the rod (F) which pushes the shoe outward. Shoe travel is restricted by the drum.
The seal (E) keeps the brake fluid inside the cylinder.
If the drum is not installed when the brake pedal is pushed the piston, rod, etc will travel outward until they pop out.
Remove the cover boot (G) and determine what parts came out of the cylinder.
If it is the piston and seal these need to be reinstalled along with the dust cover and rod.
Part D is a spring that keeps the two pistons apart.
One all the parts are back together including the drum being installed you will need to bleed the cylinder to get the air out.
There is a bleed valve on the cylinder. A Google search will turn up hit on how to bleed brakes.
When installing the seal (if pushed out) be careful as damaging it will cause fluid to leak out of the cylinder.
The slave cylinder (I) is pressurized when the brake pedal is pushed down. The pressure moves the piston, the piston moves the rod (F) which pushes the shoe outward. Shoe travel is restricted by the drum.
The seal (E) keeps the brake fluid inside the cylinder.
If the drum is not installed when the brake pedal is pushed the piston, rod, etc will travel outward until they pop out.
Remove the cover boot (G) and determine what parts came out of the cylinder.
If it is the piston and seal these need to be reinstalled along with the dust cover and rod.
Part D is a spring that keeps the two pistons apart.
One all the parts are back together including the drum being installed you will need to bleed the cylinder to get the air out.
There is a bleed valve on the cylinder. A Google search will turn up hit on how to bleed brakes.
When installing the seal (if pushed out) be careful as damaging it will cause fluid to leak out of the cylinder.