Would like some help on all three of these: 1998 XC V70

1. AWD/Tracs Light - I assume this is the control module issue the archive has so much information on. I am surprised this never came up as something vovlo would cover as it is a major safety area. Perhaps since the regular breaking system seems to work they view it as just another crappy part design from Volvo...

2. Air Pump - Now that it is cold the pump is kicking on in the morning for a few minutes but it is VERY loud. Is the issue the pump itself or perhaps just the valve. Again recommendations on dealing with this issue and what could happen if I ignore it are appreciated.

3. The car intermittantly pulls drastically to the right when braking. The frequency is pretty low (maybe once every 2-3 days). Is it possible this is related somehow to the tracs/ABS issue?

Thanks for any help/advice, Marty

The ABS/TRACS unit is a notorious problem plaguing 1996 and 1998 models. For 1998, the board cracks, usually breaking the connection to the sensor at the RR wheel (which is why a code scan points to a RR wheel sensor).

If the air Pump is operating, apparently a new checkvalve and a drainhole drilled in the bottom the the original air pump casing are quite effective (so far).

A pull to one side under braking usually indicates a sticky caliper coming on late, on the side of the car opposite to the direction it's pulling. When mine did this a few weeks ago on the 940, I squirted a small amount of high-temp Volvo silicone brake grease into the groove where the caliper parts are close together, and on the guide pins. Problem solved.

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David \\ (98 S70 T5SE Black, misc mods (mostly lighting), red calipers) (92 940GLE)

Our most recent 855 purchase was pulling to the right once and a while. The left rear caliper was found to be sticking.

I found the problem by jacking the car up each day and spinning the wheels. On the second day I found the culprit. I removed the wheel and could see a "print" from where the hot pad came to rest on the rotor.
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3 8s & 2 7s 725,000 miles total

Pulling to the right should not be a trac/abs issue. Several things could be causing that such as uneven tire pressure, lug nuts not torqued correctly, disc brake rotor warpage, brake calipers grabbing, uneven tire wear.

Also are you sure your car was level when it was pulling to the right? Most roads are not really leveled flat for flood/drainage purposes.

yes I'm sure the road was level... this is not just a weak pull. When it happens you can feel the steering wheel pull strongly to the right. My guess is some caliper is sticking every once in a while but I can't be sure...