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

Wheel Torque and Warped Rotors. Volvo rotors will warp like crazy if the wheel nuts are over-tightened and/
or not tightened evenly. If you see someone use an air wrench on your lug nuts when installing your wheels -
warped rotors are just a few miles away. Our 1988 760 has gone through several sets of rotors. The problem
has been solved since I now insist on a torque wrench being used after the lug nuts are hand tightened.
Current rotors have over 40,000 miles and are living well. When you have work done at a tire shop they are
there to do what you need done, not what is the fastest for them. Let them use the air tools on someone
else's car.
Calipers and Guide Pins:
Caliper Guide Pins: Maintenance
Guide Pin Discussion. In the Girling front brakes there is a retainer cage that fastens to two "ears" on the
axle assembly. There are 2 hex socket bolts that hold this retainer on. At the back of the retainer are two
sockets that each receive a floating locating pin encased by a rubber sleeve. The caliper is bolted to these
pins so that it is free to move sideways a centimeter or so. The pins have to be lubricated and free to move.
In my case one of these pins on each side was frozen and not moving. Thus when the brakes were applied
the pistons were able to push the inside pad out but the caliper was not able to move in and pull the outer
pad into firm contact. This caused noise and pulsing. [Tip] The front caliper is held by two floating guide pins
which move within a bushing fitted into the caliper. Often this bushing shows corrosion and the pin can not
be moved within the caliper. If so, the brake performance decreases as the two calipers cannot press the
disc properly. To inspect the functioning of the brakes: remove the guide pin bolts and pull the caliper up and
away from the guide pins. You should be able to easily move the guide pins in and out. If not, the pin or
bushing is corroded or in need of lubricant.
Removing Caliper Guide Pins. [Tip from John B] On Girling it's pretty straightforward: remove the fixing bolt,
pry the collar on the rubber boot from the caliper and then the boot and the guide pin should come out. Lube
the new pin with synthetic brake grease and insert it, put the new boot over the lip and press the collar on so
that the ridge on the rubber collar fits in the recess on the pin. On Bendix, it's a little more difficult, you have
to ensure the ridges on the boot inside mesh up with the indent on the boot mounting ridge. [Tip from
Randy] Unless they are seized the guide pins simply slide in and out after removing the brake pad. If they
are seized a good soaking with Aerokroil (or your favorite penetrating liquid) along with the application of the
correctly sized socket to add torque and a hammer to add vibration will help. Clean the hole thoroughly and
apply an anti seize compound before assembly. I actually sprayed a lot of Kroil into the boot and let it soak.
The best aid in having penetrating fluid work is TIME- as in long soak time. [Chris Herbst] One effective way
to free the pin is to turn it back and forth while trying to extract it. It's not the easiest thing to do, and if it
doesn't work, you are going to be in the market for a caliper carrier, which is not expensive.
Lubricant Recommendations. [Tip from Motor Magazine] Most brake lubricants suitable for use today are
silicone-based; petroleum-based lubes may cause some newer rubber components to swell. [Editor] Use a
brake lubricant specifically made for use on the guide pins; most will say "synthetic" or "silicone". Replace
any torn rubber covers. Check the operation and lubrication of the guide pins at each pad change.
Rebuild Kit. Volvo has available a repair kit for the lower caliper guide. Cost for the Bendix version is
approximately $30 US. Repairing the damaged caliper guide with a kit may be preferable in some
circumstances for some owners. The heart of the rebuild kit is a new guide pin with a different design from
the old one. Actually, there are two guide pin rebuild kits: one for the lower guide pin only, and one for both
upper and lower. The lower guide pin is the one that is most often jammed. To determine whether either of