Who has turned rotors?

Post by **MadeInJapan** » 29 Sep 2012, 10:44

So it has always been my take to never turn Volvo rotors- I've replaced pad sets after pad sets without doing this without any issues. However, my son's 850's front breaks squeal badly when coming to a stop. I pulled the wheels and inspected the the brakes this morning- still a lot of meat left on the genuine Volvo pads I installed last year. Rotors are scored but also not worn badly. I measured them and they are both at about 25mm... Vadis recommends replacement at 24.8mm and minimum 23mm. So, this is a cheap car (paid very little for it) and upkeep has been cheap and it's a daily driver for a young, soon to be 20 year old kid. I am tempted to just take rotors off and have them turned and scuff up the pads so they'll be like new on the fresh rotors. I have never done this before but am tempted. What say you, Matthewsvolvo folks?

Post by **JDS60R** » 29 Sep 2012, 10:51

Squeal can come from a rotor face but its a rarity. Usually it is a vibration between the pad and caliper. I would pull the pads, clean everything and re install them with some syl- glyde on the back of the pads. You can even wash the wheel and caliper assembly thoroughly first to see how it functions/squeals without the brake dust on it and before you tear into it.

I understand the cheap theory but for me ,when it comes to brakes I like them to work well. If the rotors (after cutting) will be below min spec then IMHO toss them. New rotors can be bought quite affordably these days. If cutting keeps them within specs then by all means yes- cutting them is fine.

Post by **MadeInJapan** » 29 Sep 2012, 10:58

Yes, thanks for your reply...I see what you're saying.
I just replaced the cross/drilled rotors and pads on my S70.
The V70 needs front rotors now.
The V40 seems to be in good shape (brakes just done before I got it).
850 needs some kind of brake work-

So as you can see, just keeping up with brakes much less the oil changes in 4 Volvo's takes it's toll...I think I will do your trick- clean them and put the brake gel on the backs of them and see how that goes first. It will be a close one to turn them- I think they'll remain in speck, but possibly not.

Post by **cn90** » 29 Sep 2012, 11:53

I resurfaced rotors in my cars (Honda, BMW, Volvo etc.) every 3 years or so.
I have owned many cars over the years, and roughly every 3 years, the rotors are warped a bit to cause slight vibration during braking.
Just make sure it is above 23mm.

I am a frequent customer at local O'Reilly so they resurface them for free. Otherwise it is $10/rotor.

Post by **Ozark Lee** » 29 Sep 2012, 12:06

I just had a set of cross drilled rotors turned last week. In this case they just had uneven wear from the cross drilling and they were not warped. I had a set of warped rotors turned several years ago and within a month they were warped again.

I guess my rule is that if they are warped, replace them. If they are not warped it is OK to turn them.

...Lee

Post by **MadeInJapan** » 29 Sep 2012, 12:13

I agree- I definitely need new rotors on the '04 V70...found these (same place I got my cross drilled/slotted)...it appears the later model is slightly different although size is the same 11" I thiought all 11 inch Volvo spec rotors were the same... anyway:
http://www.r1concepts.com/volvo-v70-200 ... .39029.htm
Unfortunately with the basic rotor, they do not zinc plate them- something I really like on my S70 rotors-
No rust and they look new every day!!

Post by **MadeInJapan** » 29 Sep 2012, 12:21

Haha- just found this- a bonus!!
Same company and these do have the zinc coating!
http://www.ebay.com/itm/2-FRONT-ELINE-O ... cd&vxp=mtr
I've really liked this company and their products-
My last set of drilled/slotted/zinc coated from them lasted me 6 years on my S70...ever a hiccup!
I think I'm getting these for the '04- sorry, I know this is the wrong section...they also have rotors for our older Volvos too!!

MilehighV70XC · Post by **MilehighV70XC** » 29 Sep 2012, 15:55

Warped rotors is a myth. From my experiences on the street and track this is true. If you are feeling a vibration during braking it is usually because at one point in time the brake pads exceeded there operating temps and an uneven layer of pad material has been transferred to the rotor. Brake pads work by transferring a thin layer of pad material to the rotor. When they heat up the pad grips the material that is on the rotor. The uneven layer of brake material on the rotor creates high spots. As the rotor turns is causes the pad to not contact the rotor surface evenly when the high spots pass under the pad.
I would like to hear your guys opinions.
A good read from Stoptech. One of the best companies around for brakes.
www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths

Post by **regent** » 30 Sep 2012, 14:10

I agree with high spots being the primary cause of vibration; however, with cheaper brands rotors, warpage does occur due to uneven heat transfer as a result of the non-homogenous material and non-uniform temperature field throughout the rotor. Uneven disc wear pattern can be an additional source of vibration or even cause pulsating pedal. In extreme cases I have seen failing (cracked and chipped) rotors as a combined result of the above poor material quality and severe cyclic stress due to the thermal shocks.
After resurfacing, the heat conductivity becomes worse due to the lesser thickness, which in turn leads to a higher temperature gradient and better chance of failure due to the increased stress.
The benefits of using turned rotors would therefore seldom outweigh the time one would invest for another planned maintenance. Just MHO.

Post by **MadeInJapan** » 30 Sep 2012, 16:18

Well this thread sure veered off course... Well, I turned the rotors today (still in spec)...and sanded the streaking in the pads so they were clean and looked brand new...I used plenty of the glyde goop in the calipers and behind the pads- everywhere the pads would touch...I also cleaned and lubed up the pins. Result was much better braking but stull squealing (not as bad) at the end of the stop. I have a feeling that I've never touched these brakes until now and that these are not OEM pads.. I can't remember for srue, but possibly I've never serviced the front pads on this car. I've never had OEM pads squeal after I've put them through the lube process. So, I'm hoping these pads will break in with the turned rotor and some of the squeal will go away. If not, then I'll order up some OEM pads next time they're on sale. Btw, I had no shuddering at all or pulling, etc., even before I did all of this...the only thing I had was the ABS engaging at the end of a hard brake...and that seems to have gone away!