Finallygotit
ALLIANCE MEMBER
We can no longer buy parts from Rock Auto if we live in Arizona. Some legal ******** stopped that. 
Between 485 & 705 SQ/FT Bob Heine's Auto Emporium
- Thread starter Bob Heine
- Start date
Workspaces between 485 and 705 squarefeet.
madison069
Well-known member
Seems Arizona says Rockauto owes the state taxes. So they just stopped selling in AZWe can no longer buy parts from Rock Auto if we live in Arizona. Some legal ******** stopped that.
Seems Arizona says Rockauto owes the state taxes. So they just stopped selling in AZ
Yes, well.. the only time I had a core charge was on the brake shoes, themselves. Never a drum. From what I understand, drums were considered as consumables, rotors, too. Brake shoes, a person could put new lining on, never a disc brake pad. The thing I had to be careful of when I was turning my own drums and rotors was to leave enough material left for wear, the final time I turned one. In the case of a drum, the maximum diameter. In the case of a rotor, minimum thickness. That's not numbers I could find in a Haynes or Chilton's repair manual. I was supposed to depend on the size, either stamped in or cast into the drum or rotor. In many cases, those numbers were rusted beyond recognition. In many cases, I bought a new drum or rotor, just to get that number. Then I'd pencil that into my manual so that I knew what to do at the next brake job. I always tried to keep myself honest and my family safe.
In many cases I had about .075 stk on a brand new rotor thickness. Using ceramic pads, I could turn those rotors a couple of times, and still leave .015 stk for wear on my final turning. In my experience, with your own brake lathe, it really did make sense to turn the rotors. Drum brakes, on the rear of the vehicle lasted forever... Well, the front brakes do the majority of the braking as far as percentages go. But when it came time to turn a rear drum... Those drums looked like a very small cut would clean things up. But what you didn't see is how out-of-round those things were!! ( Well maybe not out of round, but off-center...) It took many cuts to clean up a drum. It took much of your tolerance, just to get those drums to minimum clean-up.
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Both of my brake lathes would only have power feed in one direction. That bothered me at first, but I understand now. You always had to feed the boring bar into the cut with the machine running while the bar was at the furthest inside of a drum. That bothered me. My machine was set up so the boring bar swung around while the drum stayed stationary. Try to adjust that bar to an accurate size, while it was in motion, swinging around.... When you are at the very inside of the drum. The machine came equipped with a rheostat to begin with, so it had variable speed. When I bought the machine, the rheostat had failed, so I bypassed that and ran it with a Variac, instead. So I could throttle the boring bar down to a slow crawl, adjust the boring bar on the fly, then start the power feed, then crank up the Variac to a decent RPM, but not high enough to tip the machine over in this unbalanced condition... (I didn't have the machine bolted to the concrete floor). But the reason that I had to start from the inside, then feed outwards was so I could never crash that machine, because I walked away and did something else. I'd always listen to it, once I could hear that it wasn't cutting anymore, I knew to come over, reset for another cut. My rotor lathe worked in the same way.
Ohoh...We can no longer buy parts from Rock Auto if we live in Arizona. Some legal ******** stopped that.
Quite frankly, that drum lathe is pretty small in comparison to size of the metal trunk that holds all of the rest of the attachments... There's another spindle in it, so I could turn anything from a motorcycle sized drum to something on a semi- truck, and everything in between.... So, I've heard whence I bought such. I have no reason to doubt things. It's gonna be easier to move the machine than the metal trunk full of attachments. Lots of steel cones, lots of cast iron inside-out "cones" for support on the spindles. Lots of things I haven't even tried out yet...
But id agree with most people that a brake rotor doesn't really warp. That's not the issue... What really happens is that the thickness changes. A warped rotor pushes the brake pads side to side. Axial runout. And possibly a tilt to the spindle axis. Thus, making the pads try to grab at the maximum diameter of the rotor on the outside with one pad verses the minimum diameter with the inside pad, within the range of the pads. But very out of parallel between the pads and the rotor. That could very well happen, I do not disagree, but I've not witnessed that happening, myself. (I should actually see (witness) some of that, as I turn rotors)(And I have in some extent) Mostly, the thickness changes, making the pulsation happen. Now..... Bob, Squankum, Kay could speak otherwise. Bob owns Corvette cars. Squankum really got into car racing. Kay has done many brake jobs. But I really think pulsations come from thickness variations, not warping and parallelism.
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As I turn a rotor, there's a cutting tool on both sides of the rotor, cutting at the same time. It takes more than one cut, to clean things up. As it takes a few passes to clean things up, I tend to watch the pattern, of cutting and non,- cutting.
kaymccampbell
Well-known member
Good on Rock Auto. Off soapbox, before I get trip to band camp.Seems Arizona says Rockauto owes the state taxes. So they just stopped selling in AZ
gman007
Well-known member
Ok I will go first.
What happened to the “we the people”?
In Michigan the gas tax was raised by 21c to 52c , nominally to pay for fixing the roads. I have not seen any improvements and roads are as crappy as they have always been. Leave it to freaking politicians and bureaucrats to squander and piss away hard earned tax payer money.
Next please.
kaymccampbell
Well-known member
No more, please, or the mods will send you to band camp for violating the TOS.
The peculiar form of racing I was involved in was very easy on brakes! At least on our car, which kept getting lighter and lighter. So easy that we "backdated" the front rotors from the vented discs found on later VW's of that era, to the solid/unvented rotors of the diesel model. That also solved a wheel clearance problem, but it also saved weight. Then my friend laid out a pattern on these solid rotors and we whacked away on them with a 1/2" drill bit in the drill press, to save even more weight! Never had a problem with cracking that I know.
Since I gave up on the sport I think my friend has reduced even more weight out of the brakes, but in other ways, mostly calipers, as the rules got looser about what you could run for brakes.
So again, we didn't get a lot of heat or wear into our brakes, but one year we went to nationals, and famous road race care preparer Carroll Smith was there, and he gave a talk in a nearby hangar, so we went to see what he learned. According to my googling and my ten fingers tonight, that was over 20 years ago!
He didn't say anything about brakes that day that I can remember, but he did write this about brake rotors and it's worth reading:
Something else that changed in our modern times is that manufacturers took a lot of mass out of rotors, I think for EPA mpg testing. Less room for error when they get too hot. Less meat to machine -- if any.
Well, I had a pretty good evening. (Always take Fridays off as PTO). When I went out to the shop, I wanted to take a gander on my stereo, as last time out there, it would turn on, but no noise... Hmm. I hit every button on the remote, then went over and started turning knobs and things. I finally got it to work again. Whew!. That owner's manual is about 80 pages long. You just about need a college degree to run the thing. I still haven't found the tone controls on it yet, but considering buying a graphic equalizer to help with things. Anyways, my first song of choice was Fever 333, Animal. Got that downloaded to Spotify and let 'er buck about a half-dozen times in a row, at some volume while I found the new headlight assy for the Dodge Neon. I did find the headlight, that I bought in 2023....
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That's pretty neat that you drilled holes in your rotors to save weight. I would've never thought of that. But in your racing scene, every little bit helps. I always thought that by drilling holes in your rotors was a way to add to the cooling efforts of the rotor. I'm sure you've seen where a ball endmill was used to create grooves in the rotor surface, to also add to the cooling efforts.
kaymccampbell
Well-known member
I call ******** on the No Warped Rotors statement. I've turned too many rotors back into parallelism to believe that. Now the fact that the braking vibration returns quickly to turned rotors, I can attribute to cheesy modern rotors. Old school rotors had enough mass that you had a chance of restoring them to usefulness. But then they warped a lot less, if at all. Right now, I've got a warped rotor on the Escape. And it's really warped. And I'll replace it because it was too thin when new, let alone now that it's worn and warped.
kaymccampbell
Well-known member
I put the dial gauge on it. It's warped.
Coolabah
Well-known member
Good point. Just for reference , most of our early roads in Australia were built by convicts that we imported from England. A little bit before my time, but was a cheap solution a couple of centuries ago, as they cost very little rum to run. @gman007 : not sure if that scheme is still running but might be worth looking into for your state ?
HTH !
Coolabah
Well-known member
Thank you, that was indeed a concern of mine. And here I was ready to book an appointment....
It's entirely possible Carroll Smith's perspective is narrow, living in racecar land!
Was no invention on our part, drilling (or better, casting) holes to improve braking performance started with the Porsche 917 race cars of the of the late 60's/early 70's.
I believe the goal of drilling in those days was getting the gasses from the brake pads out so the gasses didn't make the brake pad float above the rotor surface. I don't think cooling was the real goal. Later on, yes, grooves were a way of getting this done, too. If you have a keen eye you can spot another tactic for extreme braking performance in the picture above.
These brake rotors and the calipers (one per wheel) did eventually make their way to some of Porsche's street cars. Dual calipers, to my knowledge, didn't show up on a street car until the Mercedes-Benz Maybach sedan/limo around 1997.
But we already knew from seeing real race cars at the autocross, and from race parts catalogs, that Formula Ford race cars were doing crazy things like this with brake rotors:
Now that's about rotational mass and unsprung weight! Although I suppose the surface area for cooling has increased, too.
Sprint cars and high-tech motorcycles have since gone on to have crazier rotors.
gman007
Well-known member
Great and interesting info. Thx for sharing !Was no invention on our part, drilling (or better, casting) holes to improve braking performance started with the Porsche 917 race cars of the of the late 60's/early 70's.
I believe the goal of drilling in those days was getting the gasses from the brake pads out so the gasses didn't make the brake pad float above the rotor surface. I don't think cooling was the real goal. Later on, yes, grooves were a way of getting this done, too. If you have a keen eye you can spot another tactic for extreme braking performance in the picture above.
These brake rotors and the calipers (one per wheel) did eventually make their way to some of Porsche's street cars. Dual calipers, to my knowledge, didn't show up on a street car until the Mercedes-Benz Maybach sedan/limo around 1997.
But we already knew from seeing real race cars at the autocross, and from race parts catalogs, that Formula Ford race cars were doing crazy things like this with brake rotors:
Now that's about rotational mass and unsprung weight! Although I suppose the surface area for cooling has increased, too.
Sprint cars and high-tech motorcycles have since gone on to have crazier rotors.
Was no invention on our part, drilling (or better, casting) holes to improve braking performance started with the Porsche 917 race cars of the of the late 60's/early 70's.
I believe the goal of drilling in those days was getting the gasses from the brake pads out so the gasses didn't make the brake pad float above the rotor surface. I don't think cooling was the real goal. Later on, yes, grooves were a way of getting this done, too. If you have a keen eye you can spot another tactic for extreme braking performance in the picture above.
These brake rotors and the calipers (one per wheel) did eventually make their way to some of Porsche's street cars. Dual calipers, to my knowledge, didn't show up on a street car until the Mercedes-Benz Maybach sedan/limo around 1997.
But we already knew from seeing real race cars at the autocross, and from race parts catalogs, that Formula Ford race cars were doing crazy things like this with brake rotors:
Now that's about rotational mass and unsprung weight! Although I suppose the surface area for cooling has increased, too.
Sprint cars and high-tech motorcycles have since gone on to have crazier rotors.
We were drilling rotors on motorcycles back in the 1970's. I'd say 99% or more were just for the "cool" factor - and, we're not talking temperature.