Bam Margera  SPOTTED AT BAR AFTER LEAVING REHAB

Bam Margera bounced early from substance abuse treatment and hit up a tavern ... and he's no longer speaking to his parents.

We're told Bam was at 57 Tavern in Sarasota until about 1 AM Monday, and it looks like he needed help walking out the front door.

He left treatment Sunday and has been telling friends and family he met a new lawyer friend in rehab who told Bam he could help him get out of his court-ordered rehab by leaving the state.

Bam is shacking up at a family friend's house in Florida ... but as of last week, he's no longer speaking to his mother and father. 

He also has not heard from his estranged wife Nikki or seen his son Phoenix since he returned to rehab at the end of June.

We've seen this pattern before from Bam ... back in June, he fled a Florida rehab center, was reported missing, surfaced at a bar, got tracked down by the cops, and was taken back for treatment.

Once this treatment center reports Bam missing -- likely in the next few days -- police and an intervention team will search for him,

with the ultimate goal of getting him back to rehab. They are hoping they can get him back into treatment on his own.