Violent vibration

[tornrock]

Every now and again my volvo starts vibrating violently.  It bucks and surges.  Pulses can be felt through the steering wheel and brakes.  If the car is shut off and restarted it stops.  After a few episodes of this we noticed the front passenger wheel was very hot.  On a hunch that the TRACS system was causing the problem we've disengaged it whenever problems occured.  One day when driving about 30mph I heard a scraping noise.  It stopped as soon as I turned the TRACS off.  This seems to have solved the problem.  The car handles better and there has been no shaking.  Mechanics can't seem the find a problem, but they sure love to charge us for looking.  Anyone have any ideas?

[methos]

Are you driving with the TRAX system on all the time?

[tornrock]

The default is for Tracs on when you start the car. I have to remember to turn it off everytime I start the car.

[ducatibrian]

i would suggest having the abs ecm checked for fault codes as this and the tracs are one in the same. it sounds like the abs thinks there is a missing wheel sensor signal and is activating the abs intermittently. it is possible that the abs ecm will need to be replaced-common problem for these. it is a definite one if the abs light flashes on at times as well.

brian

[tornrock]

The dealership claims to have checked the fault codes and found nothing.  I'm losing confidence in them.  Recently while driving along I heard the scraping sound again.  This time turning off the Tracs didn't help. Perhaps stuck caliper or emergency brake? (Dealer checked for those too.) Any thoughts out there?  Help! I love driving this car but it is driving me crazy!

[ducatibrian]

caliper problems or parking brake adjustments are rare on these models. i have done 0 calipers on any models newer than 93 in the last 5 years. i would really lean towards the abs ecm as the most common problem  but with no codes at all, it is only a guess. usually on these the tracs/abs or both lights will flash or stay on at times. the noise has several possibillities, just hard to make a good guess without actuall experiencing the noise/vibration. one other thought would be the angle gear/front differential-have the fluid checked for color-smell"burnt"-metal debris, as this is about my only other suggestion at this time. any further detail you can give? when did it start/hot or cold only-both? etc.
hth

brian

[tornrock]

Thanks for the input Brian. Haven't had any warning lights. Problems happen cold or hot. Car is used mostly for short trips and now I'm afraid to take it on Hwy. The vibration has only happened 4-5 times. I'm almost positive that is the tracs gone mad from a bump in the road.
The scraping is more frequent than the shaking but not all the time. (Radio covers it up so I don't have to hear it- that is until the door speaker quits and I have to hit the door to get it back on. But that's a differant problem&#33http://xc70.com/iB_html/non-cgi/emoticons/wink.gif It happens while driving and slows with the car / kind of matches the speed. Could the noise be the caliper scraping the raised edge of the rotor? Rotors look good-all about the same wear/ no grooves.
I thought about the differential - a few months ago it started spraying out little spots of grease under the center front as it's shut off. Dlr. said it's "normal" - from the turbo. We have two V70's and this is the first spot under either in ~6 yrs.
The latest symptom besides the intermittent scraping is the sluggish nature of the car. It takes a lot of pedal to get it going and it doesn't "coast" when you let off like it used to. Mileage is bad ~13mpg instead of usual 20+
Also, we just put the third set of tires on it w/ only 30K miles. The first @10K had tread separation on 3 of 4. The second had odd wear patterns in spite of keeping it aligned. (I don't race it - really.) Does any of this mean anything to you? I appreciate your help.
tornrock

[tornrock]

The end (I hope) of the story.  Had to have it towed.  It was a sticky caliper.  It would ratchet in and cause the noise and vibration until the pad wore down.  Things would be ok for a while.  Then randomly it would free up and clamp down again.  New caliper solved several problems. Besides the vibration, scraping and hot wheel, it also restored my braking to normal (it was hard w/ only one front brake working) and my xc has it's get up and go again!  I expect milage to improve without a brake dragging.

[AWD*V70XC]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (tornrock @ Jan. 15 2004,20:39)</td></tr><tr><td id="QUOTE">The end (I hope) of the story. Had to have it towed. It was a sticky caliper. It would ratchet in and cause the noise and vibration until the pad wore down. Things would be ok for a while. Then randomly it would free up and clamp down again. New caliper solved several problems. Besides the vibration, scraping and hot wheel, it also restored my braking to normal (it was hard w/ only one front brake working) and my xc has it&#39;s get up and go again&#33; I expect milage to improve without a brake dragging.[/QUOTE]<span id='postcolor'>
Wow... four months to sort that little baby out http://xc70.com/iB_html/non-cgi/emoticons/nervous.gif hope you didn&#39;t do any other damage? Ah well at least you have brakes now&#33; http://xc70.com/iB_html/non-cgi/emoticons/thumbs-up.gif

Wow... four months... I can&#39;t beleive it

Now you must get that speaker sorted out as well could be a loose wire.


Four months with only one brake working. (only kidding) http://xc70.com/iB_html/non-cgi/emoticons/hehe.gif

[tornrock]

Don&#39;t ya love it when the dealership says &quot;drive it a while and see what happens.&quot; When the &quot;codes&quot; didn&#39;t reveal anything, they didn&#39;t bother to investigate further. I&#39;m lucky I didn&#39;t really need the brakes. The rotor has some bluing but dealer said it was OK.
http://xc70.com/iB_html/non-cgi/emoticons/crazy.gif
I&#39;m thinking the speaker is a bad ground / cold solder. I need to find the tricks to removing the door speaker grille or door panel. Any ideas? http://xc70.com/iB_html/non-cgi/emoticons/lookaround.gif

[tornrock]

It's back! Now my DH is driving the car and says that it randomly has a scraping noise. He has been able to get it to stop by pulling and releasing the parking brake. Does anyone know what could cause the parking brake to engage while just driving along (sometimes at highway speeds)?