Greetings

My pads were replaced 4 months ago. The rotors were not. The pulsingvibrating mumbo jumbo inclines me to buy new rotors. The rotors I have are solid back, vented front. My questions are:
Will I need to new pads with the new rotors?
Should I replace the rotors with vented or solid?
Should I replace all four rotors or just the front?

Thank-you-very-much

i realize that this situation has been resolved but I wanted to add my opinion to the turning rotors question. when my 940 was 4 years old my rotors started to warp so i had them turned. they warped again after a month. i would not waste the time or energy to ever turn a rotor again.
--
'88 745T, '89 780T, '93 944T, '98 S70T5

While it is generally recommended that you use new pads with new rotors, IMHO if your old rotors are not grooved (and the pads are therefore evenly worn), you can use your present pads with new rotors.

Usually it's only the front rotors that warp since they do most of the work (and develop most of the heat), I'd replace them to see if that cures your pulsating brakes.

Replacement rotors will be similar to the OEM ones in that the fronts will be vented and the rear will be solid if that's what your originals were. You COULD buy cross-drilled or specially cut rotors (ATE makes some, for instance), but for normal use OEM style should be more than adequate.

I just bought a set of "Zimmerman" German made front rotors from FCP Groton for $32 ea. (and used them with my "used" pads, by the way) and I am very happy with them.

If you do buy new pads, PRB Deluxe or Metal Masters are excellent, non dusting pads at reasonable prices. I believe FCP Groton sells them as well.

Bob

That was my next question.

I'll buy the Zimmerman's vented then.

Thanks a bunch.

Hello Raja,

I had the same problem on my '95 945. You cannot have the stock Volvo rotors turned. I replaced with Brembo rotors, vented front and solid rears. Cured the problem and they can be turned when needed.

Hope this helps, good luck.

Mike K.

Why do you say one cannot turn stock Volvo rotors?
I turned my rotors myself and they became perfectly true and has not warped since. IMHO opinion as long as you don't run them thinner than the specified minimum thickness they should be OK.
I've heard this story about rotors and it looks plausible;
after manufacturing there could be inherent tension in the cast iron. When you brake and they heat they also warp as this tension shapes the hot rotor. If you turn them now when this tension is removed they will not warp again.
Unless you don't torque the wheels properly of course.


Happy bricking
Mikael Larsson

While in theory turning rotors should work fine, in more cases than not with import rotors* (or composite rotors where cast surfaces are mated to sheet steel centers on domestic cars) I have found that turned rotors often rewarp even when they are left at or above minimum thickness.

With decent quality rotors available at only $30 or so each, paying $12-14 to have a used rotor turned may not demonstrate a good risk to reward ratio. Also most shops don't put a comparable surface finish on their rotors compared to new factory rotors. At my former shop (mostly BMWs) I finally gave up on turned rotors due to come-backs for rewarping and brake noise (accentuated by improper surface finish).

Bob
*I am not sure it's the material or the thickness of one-piece domestic rotors that makes them less susceptible to rewarping.

I have never seen such an animal as an composite rotor and it really doesn't sound possible to turn one like that.
What Mike claimed was that the stock rotors cannot be turned while the Brembos can.
This is clearly not true but whether it is economical or not is a totally different question. In my case it was since I turned them myself (cost zero) and have driven about 150000 km since.
If they warp shortly after turning then the rotor is probably to old and rusted. Then the two halves of the ventilated rotor is beginning to separate.

I agree completely with you. It is a waste of money to turn rotors. Sometimes they run fine, but often they quickly warp. Then you are out the cost and trouble of turning the rotors, and you have to install new rotors.

This white paper has completely revised my thinking on the care and feeding of brakes!

http://www.stoptech.com/whitepapers/warped_rotors_myth.htm
--
'96 965 with 16' wheels at 97K. Had '85 745 Turbo Diesel for 200K.

That is an excellent article and well explains the causes of the problem. I have known for a long time that new discs could be ground or turned true with no ill effects, but turning used rotors usually did not work.