Volvo Maintenance Hints for 7xx/9xx - Bill Garland's Nuclear ...

Replacing Vacuum Servos in ACC/ECC-Equipped 700/900 Cars
Volvo Maintenance FAQ for 7xx/9xx/90
Cars HVAC
Home Version 7.5
OEM Manual Procedure for Replacing Vacuum Servos. See the FAQ file for a
large .pdf describing the official procedure with diagrams, courtesy Volvo Car
Corporation (copyright; all rights reserved).
Replacing the Vacuum Servo on 700/900 with ACC/ECC Double-Acting Servos.
[Procedure from Dick Riess, to whom thanks are given; some notes from Dan]
The following is a shortcut for installing the replacement vacuum valve involved with
this problem. It is assumed that the old valve has proven faulty. Tom Irwin led me
through my replacement and I feel the information can save much time and money.
Tom Irwin did his on a 960 and I did mine on a 940 se. Basically it will include most 7
and 9 series that have that double acting valve. Believe this tends to be in the
automatically controlled heating-ac cars. They all look alike from my studying the
manuals. Warning! You cannot overestimate how long this job will take you. Leave
plenty of time to go to stores for extra bits and pieces. Do not attempt with a sore back
or hangover.
Tools required
● Small hacksaws. Pointed saw works best for starting cuts.
● Drill, approximately 1/8 inch.
● 10-mm socket to disconnect old valve and install new valve.
● Sidewinder 1/4-inch drive socket.
● Mirror to see where mounting nuts are located.
● Masking tape to line inside of 10-mm socket to hold nut in place.
● J-B Weld or similar substance.
● Black silicone RTV for caulking.
● Black or other color duct-tape.
Arrange car with the seat back. Pad the area with blankets to prevent bodily injury.
Remove under-dash cover and bolster.
Picture #1 - Mark the area to be cut. Note the box in the picture and chalk marks.
These are on the left side of the box. Drill 1/4-inch holes at the top left, top right, going