Audi A4 2001 Owner's Manual page 30

Running gear
Single-stage ABS return pump
The graphic shows a comparison of the
suction volumes of both pump versions.
In the single-stage ABS return pump, the
entire suction volume must be drawn in and
flow through the suction line during one
piston stroke (piston stroke from TDC to BDC).
30
Suction volumes
UT OT
Suction volumes
UT OT
The suction pressure is correspondingly high
and increases with increasing viscosity.
Cavitation and the associated drop in
performance on the pressure side, are the
results.
UT OT
UT OT
SSP254_095
UT
UT