HI Diane,

The 1940 Census hasn't been released yet. The social security death index was the only place I was able to find your father. I think I may have found your grandparents, though.

Social Security Death Index Record
about John Bias
Name: John Bias
SSN:
Last Residence: 14608 Rochester, Monroe, New York, United States of
America
Born: 12 Jan 1933
Died: 13 Dec 1992
State (Year) SSN issued: South Carolina (Before 1951 )

1920 Census Blackville, Barnwell Co., SC
Frank Jenkins Head M B 41 married b. SC Father SC Mother SC Occu:
Farmer General Farm
Hattie Jenkins Wife F B 35 married b. SC Father SC Mother SC
Estell Jenkins Daughter F B 17 single b. SC Father SC Mother SC
Mattie Jenkins Daughter F B 16 single b. SC Father SC Mother SC
Minnie Jenkins Daughter F B 7 single b. SC Father SC Mother SC
Ramell Jenkins Daughter F B 5 single b. SC Father SC Mother SC
Eligan (Eligah?) Jenkins Son M B 1 single b. SC Father SC Mother SC

1930 Census Bamberg, Bamberg Co., SC
Frank Jenkins Head M Neg 57 married 1st time at age 28 b. SC Father
SC Mother SC Occu: Farmer General Farm
Annie Jenkins Wife F Neg 59 married 1st time at age 30 b. SC Father
SC Mother SC
Minnie Bell Jenkins Daughter F B 17 single b. SC Father SC Mother SC
Remie Jenkins Daughter F B 16 single b. SC Father SC Mother SC
Annie Mae Jenkins Daughter F B 10 single b. SC Father SC Mother SC

1910 Census Bamberg, Bamberg Co., SC
Willie Bias Head M B 35 married 16 yrs - 1st marriage b. SC Father SC Mother SC Occu: Farmer Home Farm
Janie Bias Wife F B 35 married 16 yrs - 2nd marriage 7 children born 6 still living b. SC Father SC Mother SC
Charley Bias Son M B 17 single b. SC Father SC Mother SC
Rosa Bias Daughter F B 15 single b. SC Father SC Mother SC
Lizzie Bias Daughter F B 13 single b. SC Father SC Mother SC
Willie Bias Jr Son M B 10 single b. SC Father SC Mother SC
James Bias Son M B 5 single b. SC Father SC Mother SC
John Bias Son M B 2 single b. SC Father SC Mother SC

I'm not sure where John was in 1930, but I found his father.

1930 Census Bamberg, Bamberg Co., SC
Willie Bias Head M Neg 52 married 1st time at age 18 b. SC Father
SC Mother SC Occu: farmer General farm
Hattie Bias Wife F Neg 30 married 1st time at age 30 b. SC Father SC
Mother SC
Salomon Bias M Neg 18 single b. SC Father SC Mother SC Occu: Farm
Laborer