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| Slotted rotors... https://slantsix.org/forum/viewtopic.php?t=23434 |
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| Author: | Jopapa [ Fri Jun 01, 2007 7:52 pm ] |
| Post subject: | Slotted rotors... |
Isn't there anyone out there who makes just slotted rotors for later A bodies? All I can find are slotted and cross drilled, or just cross drilled, and I do NOT want cross drilled rotors. I love the benefits of slotted though, and want to put slotted rotors on my Duster if I can find a pair. |
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| Author: | SlantSixDan [ Fri Jun 01, 2007 11:01 pm ] |
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If you just gotta have slotted rotors or you'll die, Centric Parts might have them for you (Google it). But you don't need 'em. Just put two 45° slots in each brake pad, oriented in each pad such that the slot runs from the rear-inboard to the front-outboard, and you've got all the benefits with none of the drawbacks and a great deal less time and hassle. If you make your slots with a hacksaw as I do, wear dust protection for your lungs and eyes. |
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| Author: | green convertible [ Sun Jun 10, 2007 12:34 am ] |
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dan, thats a really good idea! I might try that myself. Drilling and slotting (I am told by people who sell slotted disks for mitsu 300gtvr4) is to get rid of the vaporized pad gas and dust (mostly gas at high temps) because the brake fade at high temps is due to the layer of gas between the disk and the pad (spongy pedal is the fluid vaporizing) Slotting the pad should be just as effective at gas release as slotting the rotor and a lot cheaper. Its exacltly like having tires with tread for contacting through water, you are making an escape passage for the gas like you do for water. |
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| Author: | SlantSixDan [ Sun Jun 10, 2007 11:17 am ] |
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Yup, that's exactly what slots are for. When I do this, I place the two slots so as to divide the pad evenly into three, and I don't cut the slot all the way down to the metal pad plate. |
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| Author: | Matt Cramer [ Sun Jun 10, 2007 12:52 pm ] |
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However, most modern brake pads don't outgas very much, either. Nowadays the only real reason for drilling rotors is to save weight. Which is a good thing on a motorcycle, where the rotors are often larger than heat requirements call for, but not so helpful on street cars where the weight absorbs heat. |
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| Author: | sethmcneil [ Wed Jun 13, 2007 7:53 am ] |
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So, if slotted rotors (or pads) are an effort to reduce brake fade; what would keep one from doing the same to the shoes on ye-'ol drum brakes, which by nature are more susceptible to fade? |
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| Author: | SlantSixDan [ Wed Jun 13, 2007 8:50 am ] |
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Not a thing. I've never done it, but I think I'd employ the same diagonal hacksaw technique with the shoes gripped firmly in a bench vise (and all the same breathing protections!). I'd probably slant the slots so that they ran from aft-outboard to forward-inboard on each shoe as installed, so as to channel the gas to the shortest path of escape. |
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| Author: | dakight [ Wed Jun 13, 2007 11:12 am ] |
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I used to do that but not to control fade but rather to control brake squeal. The mechanism of fade is different for drum brakes as opposed to discs. In drum brakes fade happens because the heat causes the drum to expand away from the shoes, requiring more pedal travel to exert the needed braking force. Moisture and dirt can contribute to poor brake performance but thermal expansion of the drum is the primary culprit. |
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| Author: | AnotherSix [ Wed Jun 13, 2007 2:21 pm ] |
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I once saw some old pictures of the brakes on a early Corvette that was road race prepped. The lining on the shoes was segmented at about 2" intervals. I think they were metallic linings, so maybe this was not for the same intended purpose, but rather to deal with expansion of the lining. Drum brakes fade for two main reasons: they cannot shed as much heat as a disc setup can and the lining that has to be used cannot function at higher temps as well as disc pad linings can. One of the problems I see with most drilled or slotted rotors is that they often start out with the lowest quality rotor they can get and turn it into a "high performance part". They start out as junk and cutting and drilling does not help. With good ones it does not seem to hurt, I've yet to see a good one crack. I tend to believe they stop better when they are wet. I just try to get the best quality stock type rotors I can find. Most late model cars have some form of slots in the pads, even if it is only one slot. |
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| Author: | Rug_Trucker [ Sun Aug 26, 2007 5:55 am ] |
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I talked with a guy at a Mopar show once that swore on the old drum brake cop cars that some had holes drilled in the drums. This was just before discs were used. |
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| Author: | SlantSixDan [ Sun Aug 26, 2007 8:59 am ] |
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Yeah, they installed drilled drums on cop cars with the 383 max wedge hemi. People "remember" all kinds of stuff that never existed. It's possible someone drilled holes in brake drums, but they didn't come that way ex-factory. |
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| Author: | slantzilla [ Sun Aug 26, 2007 9:48 am ] |
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Quote: Yeah, they installed drilled drums on cop cars with the 383 max wedge hemi. People "remember" all kinds of stuff that never existed. It's possible someone drilled holes in brake drums, but they didn't come that way ex-factory.
I remember seeing drums with holes through the face of them, but not through the braking surface. I figured somebody had hole sawed them. Also figured they'd whistle like an old top. 
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| Author: | Bren67Cuda904 [ Sun Aug 26, 2007 9:52 am ] |
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Quote:
I remember seeing drums with holes through the face of them, but not through the braking surface. I figured somebody had hole sawed them. Also figured they'd whistle like an old top.
The holes (x5) are there so you can mount them over the studs. 
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| Author: | slantzilla [ Sun Aug 26, 2007 10:09 am ] |
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Quote: Quote:
I remember seeing drums with holes through the face of them, but not through the braking surface. I figured somebody had hole sawed them. Also figured they'd whistle like an old top.
The holes (x5) are there so you can mount them over the studs.
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| Author: | Rug_Trucker [ Sun Aug 26, 2007 10:29 am ] |
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[quote="sla I remember seeing drums with holes through the face of them, but not through the braking surface. I figured somebody had hole sawed them. Also figured they'd whistle like an old top. [/quote]VW had them so you could adjust the brakes. Just one hole. |
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