If only you had a high speed connection, you could grab this 1995 manual. Much of it is still relevent to the newer cars.
Be careful getting the electrical connection apart. The plastic is old and brittle. It is also full of dirt, so making it wet might help.

The sensor is on the wheel brace, you will easily see it after the wheel is off the car.

Klaus


ANTI-LOCK BRAKE SYSTEM & TRACTION CONTROL
1995 Volvo 850

FRONT & REAR WHEEL SENSOR
Removal
Turn ignition off. Disconnect negative battery cable. Remove
wheel. Carefully clean sensor and electrical connector. Remove sensor
mounting bolt and pull out sensor. Disconnect electrical connector.
See Fig. 7 or 8.
Installation
Clean dirt and rust from sensor seat so sensor is located
correctly against pulse wheel. Using a soft brush, brush dirt from
pulse wheel. Replace sensor and tighten screw to 84 INCH lbs. (10 N.
m). Reconnect electrical connector. Install wheel. Display any DTCs
stored in control module, then erase them. Test drive vehicle,
ensuring ABS warning indicator goes out. Display any DTCs, ensuring
DTC 1-1-1 is displayed.
Fig. 7: Removing Front Wheel Sensor
Courtesy of Volvo Cars of North America
Fig. 8: Removing Rear Wheel Sensor
Courtesy of Volvo Cars of North America
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1995 854T and 1998 V70R