Since Brudes competed in the 1952 German GP you will easily find his dates of birth and death on the web (for example here: http://www.gpracing..../careers/97.cfm) : Born 15 Oct 1899 in Kotulin near Breslau (today Wroclaw in Poland, then belonging to the “German Reich”), died 05 Nov 1986 in Bremen (he is indeed one of the oldest drivers ever in the F1-World Championship ). BTW, Kotulin : I wonder if there is a connection to Freddy Kottulinsky ?
Brudes worked as a car mechanic, in the thirties he opened a BMW- and Auto Union-dealership in Breslau. He started his racing career with motorbikes (BMW, Norton) – there seems to have been a very active motorbikeracing-scene in Breslau before the war, Kurt Mansfeld, Hans-Joachim Lommel (brother-in-law to Emil Vorster – sorry for that

The records I have compiled so far show that until the mid-thirties Brudes raced bikes and cars, sometimes even at the same event – unfortunately most of the (many) hillclimbs are unknown territory for me, but Lückendorf may be a fitting example.
1928
April 29 Lückendorf (Hillclimb)
at least 2 BMW-Motorbikes (one with sidecar), one win
1929
May 26 Lückendorf (Hillclimb)
at least 2 BMW-Motorbikes (one with sidecar)
1. racecars up to 1150cc (make unknown)
1930
February 2 Isergebirgsrennen (Hillclimb)
1. overall racecars (Bugatti T37A)
May 18 Lückendorf (Hillclimb)
did qualifying in 5 classes ! (bikes and cars)
2. racecars up to 1500cc (Bugatti)
August 24 Riesengebirge (Hillclimb)
1.overall (Bugatti T37A)
1931
February 8 Isergebirgsrennen (Hillclimb)
1. overall (Bugatti T37A)
May 17 Lückendorf (Hillclimb)
at least 2 BMW-Motorbikes (one with sidecar)
1. racecars up to 1500cc (Bugatti)
overall: 8. (BMW 1000), 13. (Bugatti), 35. (BMW sidecar)
1932
May 22 AVUS
ret racecars up to 1500cc (Bugatti T37A)
June 26 Lückendorf (Hillclimb)
at least 3 motorbikes (BMW 1000, Norton 350, Special 500)
1. racecars up to 1500cc (Bugatti)
overall: 11., 16. (Bugatti), 20., 25.
1933
May 14 Lückendorf (Hillclimb)
2. racecars up to 1500cc (Bugatti)
3. motorbikes up to 1000cc (Norton)
May 21 AVUS
ret racecars up to 1500cc (Bugatti T37A)
1934
June 1 Nürburgring Eifelrennen
1. racecars up to 800cc (MG)
August 12 Lückendorf (Hillclimb)
2. + 4. cars up to 800cc (MG + BMW)
3. motorbikes up to 500cc (Norton)

On Leif`s website Hans Etzrodt states that Brudes aquired the Emil Frankl-Bugatti T35B after the latter`s death in 1934. He also seems to have bought a MG C-type (ex-Eddie Hall) that he raced in the small class against Kohlrausch, Bäumer et.al. In 1936, aged 37!, he took part in the Auto Union new-driver-evaluation test at the Nürburgring, but clearly lost out against HP Müller.
So in 1937 he took the next step and became one of the growing number of private BMW 328 owners. His showings earned him a place in the works-team for the 1938 Spa 24 hours and the 1940 Mille Miglia.
1937
June 13 Nürburgring Eifelrennen: ?
July 18 Riesengebirge (Hillclimb) : 1.
August 1 Großer Bergpreis v. Deutschland Schauinsland (Hillclimb) : 2.
August 29 Hohensyburger Dreiecksrennen: 1.

1938
May 8 Hamburger Stadtparkrennen: 5.
May 22 Avus: 3.
July 10 24heures Spa: 4. (2nd in class) with Paul Heinemann, works-BMW
1939
May 7 Hamburger Stadtparkrennen: 4.
1940
April 28 Mille Miglia: 3. with Ralph Roese, works-BMW
This is all I have, concerning the pre-war years. Before we move on - any further results, details on cars or even pictures are very much appreciated.