Toilet bubble and overflow
We lived in a house build in 1959 when we moved in a couple years ago one of the previous owner convert the garage into bedroom with bath room shower and toilet added to be second bathroom.
The sewer system were working fine until couple days ago when taking a shower in the house the toilet in the converted garage starting to bubble up, and when flushed the toilet in the house the toilet in converted garage water was sucked out almost dry, and then try to flush toilet one at a time both toilet overflow all over the floor.
Could anyone tell me how to troubleshoot the system and fix the problem?
Thanks
Art