It is not a car that you paid $ 30,000 for.
It is a lawn mower that has to be the cheapest possible to make because people will not pay a fair & reasonable price for anything now days.
Thus there is only 1 ONE brake which you can see on the diagram that Ilengine directed you to in the 2nd post.
As you have already determined the parking brake is nothing more than a mechanism that locks the foot brake in the on position.
On the diagram that Ilengine directed you to you will see nut # 50 this pulls lever # 69 harder against pins # 67 which push the brake block # 65 harder against the brake rotor # 64 which floats on splines ( not shown ) on shaft # 44 and get sandwiched between the two brake pads.
Now shaft # 44 is the gear box layshaft.
What is not apparent from the diagram is the lever part # 69 has a longitudinal V bend which makes it a face cam.
The close it gets pulled in the more it pushes on the pins thus the BRAKE ALONE gets adjusted by turning the nut # 50
So take the right wheel off.
Remove the caliper by taking off the bolts , parts # 71 & # 72, note they are different.
Now remove the caliper part #66 and the rotor part # 64.
Clean the splines on shaft # 44 and coat it with a dry lubricant like white chassis grease or push bike chain / cable lube.
Remove the pins , part # 67 and polish them, reassemble with some never sieze or the same dry lube used on the shaft # 44 splines.
AFAIK , Tecumseh brake pads , part # 799021A will drop strait in.
Reassemble the entire brake & back off the nut you have overtightened by the same amount you overtightened it.
put the back wheels on , set the parking brake , put the trans in neutral and try to push the mower
Adjust the nut # 50 till the mower wheels lock up when you try to push it.
pop a brick in the mower then go to the steepest hill on your property.
Set the brake.
If the mower moves down hill. slip the brick under the front wheel and tighten nut # 50, one flat at a time till the mower no longer rolls