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Question on truing my brake rotors


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I wrote earlier this week about my oscillation/uneven braking. The manual states the following concerning turning the rotors on a lathe. Can someone please tell me what this means? Is it something a machine shop will know when I go in there and tell them what I need, and, does this imply that the hub needs to with the rotor for turning? Thanks.

The lathe must machine both sides of the rotor simultaneously with dual cutter heads. Equipment capable of machining only one side at a time may produce a tapered rotor. A hub mounted on-vehicle lathe is recommended. This type of lathe trues the rotor to the vehicles hub/bearing.

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The key to having a hub rotor turned is to take it somewhere that does big truck work. A lot of big trucks use the same type rotor for the front so they will have the proper equipment to do dual lathe. Most small shops will not be able to do it. Just for the same of it, I would call around and price the work and price new rotors, it may be simpler/cheaper in the overall to just purchase new ones. GL

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That's and idea. Is anyone using these slotted rotors: http://www.rockauto.com/catalog/moreinfo.php?pk=3806838&cc=1377569 Kind of pricey, but come with the pads as well, which I know I need to change. My local auto shop will do a rotor for 15$, trued with the bearing race, though, so will have to give new rotors some thought. There's also these from rock auto for a little less: http://www.rockauto.com/catalog/moreinfo.php?pk=4659573&cc=1377569

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That's and idea. Is anyone using these slotted rotors: http://www.rockauto.com/catalog/moreinfo.php?pk=3806838&cc=1377569 Kind of pricey, but come with the pads as well, which I know I need to change. My local auto shop will do a rotor for 15$, trued with the bearing race, though, so will have to give new rotors some thought. There's also these from rock auto for a little less: http://www.rockauto.com/catalog/moreinfo.php?pk=4659573&cc=1377569

Not all rotors can be turned. There is a minimum thickness that is required so if you are thinking of having them turned then the shop doing the work will inspect them for the remaining thickness before they would even turn them. So turning the rotors may ar maynot be an option. Rockauto as well as other parts suppliers have OEM type rotors and they are fairly easy to install. If you don't buy some cheap Chinese made rotors then you should get similar life out of the replacement as you did on the original rotors. I run the Power Stop slotted rotors (and these are made in China) on my gen 2 truck and I really like them. I also use the Hawk (heavy duty pad for towing vehicles) pads and I really like the improvement in braking as compared to the OEM setup that came with the truck. There has always been a discussion about using slotted and/or drilled rotors and the thought being that less surface area means less braking capacity when compared to non-slotted or drilled rotors. Then there is the thought that slotted and/or drilled rotors add braking because they dissipate the heat quicker than non-slotted. There are also rotors that are cryogenic treated and that is purported to add toughness to the rotors. Heat is the killer for warping rotors. I have had very good performance with my slotted rotors and I am planning to put them on my gen 3 truck when it's time for new ones.
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Most auto shops and even tire shops have a brake lathe. Some can even be done without even taking the rotors off the truck. Drums can be turned too but those have to be removed obviously. As far as I know, most orielly's auto houses can actually turn rotors/drums too now. I dont mean to step on toes or argue with anyone but 99.8% of all big trucks (class 8) still use drums on the steer axle. Most of the time they dont lathe the drums, they just replace. Unless you were just talking about medium duty trucks....

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Most auto shops and even tire shops have a brake lathe. Some can even be done without even taking the rotors off the truck. Drums can be turned too but those have to be removed obviously. As far as I know, most orielly's auto houses can actually turn rotors/drums too now. I dont mean to step on toes or argue with anyone but 99.8% of all big trucks (class 8) still use drums on the steer axle. Most of the time they dont lathe the drums, they just replace. Unless you were just talking about medium duty trucks....

I would not take our rotors or drums to most auto shops. Most brake cutting machines at auto stores suck and are operated by non-mechanics or knuckleheads working the counter. I agree with a previous poster, either get new high quality rotors or take them to a reputable brake shop. Grinding is the best however the thickness first must be measured. To thin = new rotors needed no question. The problem with lathe style cutters is the cutting tool tends to walk over any variables without cutting true. Grinding does not do this. The pulsing sensation you are feeling is due to face runout. Basically the thickness is variable (a few thousandths is enough to cause the issue) through the circumfrance (like a warped record, but it's to slight to see with the naked eye). PS when it comes to brake parts, don't be looking for bargains. Get the best top of the line stuff from NAPA etc. Make sure (you have to ask) that it's not made in china. And don't bother with slotted or dimpled rotors. No real tangible improvement. Yea, they look neet and you might get a few high fives from your buddies but realistically the bang is not worth the buck and grooves/slots = less braking surface area. Another point to ponder: Low quality rotors and drums are often known to be out of balance enough to notice vibrations at high speeds. This sometimes happens with higher quality parts too. I ALWAYS get my drums and rotors balanced.
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Ive heard some good things from a hotshot driver who runs his trucks loaded and hard from egr, although I dont have any personal experience. Im running ebc slotted rotors and the reccommended pads, big improvement over the 2 sets of oem style rotors I trashed on my 00. They are a simple yet very functional, more than just a feel good part to throw on. Guys with manual transmissions and or exhaust brakes scoff at them but the automatic crowd needs every little bit we can get to help out. IMO the brakes on these trucks are substantially under sized, especially the earlier trucks with single piston calipers and rear drum brakes. http://www.egrbrakes.com/index-main.htm

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I got a friend's dad to put my rotors up on a lathe and turn them true. He fiddled around with getting them exactly perfect in the lathe for nearly 30 minutes a piece. Then only turned about 5 to 10 thousandths off all 4 rotors. Absolutely smooth and great braking. (Thank you Relentless70) :thumbup2:

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