The wheels on the bus Mystery Cache

The cache is not at the listed coordinates....

You will find it at: S 31 56.ABC E 115 DE.FGH
Where:
A = s+x
B = x+z
C = u
D = t-w
E = x+u
F = z
G = w+z
H = y+v

And:
s = 10513
t = 10759
u = 11596
v = 20911
w = 14598
x = 18112
y = 20167
z = 10155

You can check your answers for this puzzle on GeoChecker.com.

Congratulations to .K.B. for a quick FTF!