Family #Dh059 or Dh042 in the 1798 Dönhof census.
Family #203 and #95 in the 1834 Grimm census.
1834 Grimm Census, Family #95 
1834 Grimm Census, Family #203 
According to notes in the 1834 census, an unknown Steinbrecker was the father of Konrad Steinbrecher. Konrad's mother was "an unnamed daughter" of Heinrich Stähle. Konrad was born in 1808, so one of Heinrich Stähle's daughters had to be old enough to have a child in that year. A review of the 1798 Grimm census shows he had only one daughter who could have been Konrad's mother: Charlotte, born in 1790. She would have been 17 at the time of Konrad's birth. 
As a rule, the census notes, when applicable, that a child was illegitimate. That is not the case with Konrad Steinbrecher. It appears that his mother, Charlotte, was first married to Mr. Steinbrecher. After his death, she married Johann Jakob Meisner. She was still alive at the time of the 1857 census.
It appears that after the death of Mr. Steinbrecher, she remarried, but that wasn't until after 1829. Konrad would have already been an adult, so there was no need for him to move with his mother to a new household. Additionally, Konrad did marry before 1834 and he moved to his wife's household, the Roths, family #203. He may not have lived long with his maternal grandparents after his mother remarried, if at all.
I reviewed the 1798 Census of the German Colonies along the Volga and found Steinbrechers in only two colonies: Dönhof and Galka.  Dönhof was relatively close to Grimm while Galka was one of the southern colonies. It seems much more likely that Konrad's father was from Dönhof.
The following men were identified as Steinbrechers living in Dönhof in 1798:
Balthasar and David were brothers; their father was Adolph Steinbrecher from Hessen-Darmstadt.
It should also be noted that both the Stähle and Steinbrecher families immigrated first to Denmark, and then later to Russia.  The Stähle's ended up in Grimm, and the Steinbrecher's went to Dönhof. Despite the fact that they went to different Volga colonies, they most likely were acquainted and continued their friendships after they arrived in Russia. This may help explain how the involved parties knew each other.
Have you taken a DNA test? If so, login to add it. If not, see our friends at Ancestry DNA.
Konrad is 25 degrees from Johnny Cash, 27 degrees from Patsy Cline, 34 degrees from Gordon Kirkpatrick, 40 degrees from Ruby Hunter, 37 degrees from Reg Lindsay, 30 degrees from Don Messer, 37 degrees from Charley Pride, 29 degrees from Hank Williams, 26 degrees from Tammy Richie and 27 degrees from Laura DeSpain on our single family tree. Login to find your connection.