He was cleared of a further two charges of indecent sexual assault.
Brushett , 55, of Stacey Road, Dinas Powys, has already been convicted of six charges of indecent assault, two of actual bodily harm and five of child cruelty against a total of 16 victims.
The offences occured while he was the headmaster at the Bryn y Don residential school and home at Dinas Powys near Cardiff.
The jury has now spent 24 hours considering its verdict and still has a further six charges to decide upon.
The judge Peter Jacobs has now sent them home for the weekend.
The defendant has also been found not guilty of two charges of indecent assault.
At the beginning of the trial, prosecutor Christopher Llewellyn-Jones, QC, told the court that during his six years at the school Brushett "abused his power and his position as headmaster".
Operation Goldfinch
Brushett, who became a social services inspector for the Welsh Office after leaving the special residential school, denies all the charges.
The defendant was arrested by detectives working on the Operation Goldfinch investigation into abuse at children's homes in south Wales.
He has been suspended from his job by the National Assembly.