No doubt, Bob Ewell was trying to break into Judge Taylor's house because Bob Ewell is a dangerous man. If he will abuse his own daughter, he will harm anyone:
Bob Ewell is an alcoholic and violent man, who manufactures the rape charge against Tom Robinson in order to protect any reputation his daughter may have.
Most likely, Bob Ewell had the intention to hurt Judge Taylor. He was furious with Atticus for exposing his devious behavior, and since Judge Taylor had appointed Atticus as Tom Robinson's lawyer, Ewell was incensed against Judge Taylor. Atticus humiliated Ewell and Ewell proved how dangerous he could be when he attacked Jem and Scout to get back at Atticus.
Clearly, Bob Ewell has no character. He is a man without integrity. He spends his welfare check on alcohol. He is clearly defined as white trash in the novel. Bob Ewell beat and possibly raped his own daughter because he caught her kissing Tom Robinson. Any man that would harm his own children would definitely harm Judge Taylor. Bob Ewell is angry with anyone who tried to expose his shameful behavior:
Angered and shamed by his exposure on the witness stand, Ewell makes threats to Atlicus and others involved in the trial, but never risks direct confrontation.
Judge Taylor is fortunate to not have been harmed by Bob Ewell when he tried to break into Judge Taylor's house. Because Judge Taylor has a part in Bob Ewell's humiliation, Ewell was determined to take out his anger on Judge Taylor:
Ewell also continues to punish those he feels are responsible for his humiliation by breaking into Judge Taylor’s house.