C5 Brake swap brackets, aluminum instead of steel?
 

The C5 brake swap calls for custom 1/2" think brackets to be fabricated out of Steel. Is the 1/2" thick steel overkill for this application? Could Aluminum be used in its place? I would think that the design of the bracket may need to be different for aluminum, to beef up the areas around the bolt holts. Comments...Suggestions....

think i'd stick with steel.

Thats not exactly scientific.... Any hard facts on why using aluminum would be a bad idea?

when you apply stress to steel, there becomes a point where it fails. however if you remain below that point, the steel does not fail.

aluminum is a little diffrent. every time you stress it, even well below that failure point, it fatigues.. as it fatigues the failure point becomes lower and lower... until the part fails.

that is why airplanes and other critical machines that are made of alum require alot of inspection.. you want to catch it before it happens.

thats also why older alum roller rockers generally dont see over 100,000 miles... im not positive whats diffrent about the LT1/LS1 ones now, but im sure the metallurgy has advanced some to allow longer intervals between rocker replacement... however they will still eventually fail.


just think of it this way.... your spindle is cast IRON... even with heavy steel, you're still losing weight on it.

OK, thats better. I was doing some research and thats basically the conclusion I got. However, how can Wilwood make entire hubs out of aluminum, as well as rotor hats? Also, airplanes undergo quite a buit more stress than a car, and I'm not positive about this, but I'm not sure sure the airplanes make use of much half inch aluminum. Arent there CAD programs out there that can simulate stresses on different materials? I think this would be a perfect canidate to test in one of those apps.

they also make the calipers out of alum.

what wilwood does is make race parts. they make them so overkill that the caliper will probly be worn before it fatigues to the failure point. you can overbuild somthing so that it wont fail for the life of the part.

problem is, we're backyard mechanics and machinests.. we arnt spending 1000s on research and development to simulate and then test and validate the simulations.... esp to only save a few oz of weight on a spindle that you just chopped pounds of iron on.

so can it be done? yes. will it be proven safe? no. is anyone here making the parts willing to take the risk of selling a brake bracket that can possibly fail? no.

id rather err on the heavy and overbuilt side then risk it.

its like the guy with the alum lower control arm webpage... yea, they'll work.. and that is a insane amount of PSI before it should fail...
then again, ever measure the amount of stress a 50 mph pothole puts on the LCA? thats why spohn, BMR, and others dont make them from alum.

One of the problems right now is. Steel is very expensive. Much of it is being shipped out of the country (eg. Afghanistan and Iraq). 1/2 inch thick steel is espically expensive. Aluminum is much easier to mill and its also easier to find at a decent price. A few people I know of who are race car guys and work in the business, said aluminum should work as well as steel, espically since its so thick.

I can understand why steel is better but aluminum won't exactly break if its being stressed either. It will just bend. Going with aluminum isn't about saving weight, its about cost.

I'd rather spend a few extra bucks now, rather than spending hundreds later to replace wheels, calipers, spindles, rotors, etc, and possibly medical costs if a caliper comes off or something and/or a front wheel locks up. I swear I found a freeware, or trial version of a CAD program that could run simulations on this sort of stuff....

Scott

Steel isnt that much more expensive. Here's an eBay auction for some stainless: http://cgi.ebay.com/ws/eBayISAPI.dll...ategory=41962, enough to make about 10 sets of brackets. Stainless probably isnt the material of choice though.

steel is priced by the type and by the pound, not the size it is. anyone that thinks they're goingto save money by using aluminum instead of steel needs to set the crack pipe down and price the two. aluminum will exactily break if it's stressed, just like steel will, only at a lower point. add to that the fact the aluminum will stress crack/fail ought to be enough to convince most people to reconsider it's use in critical componets, liek brakes and brackets.

The brake area is not a place that I would personally use aluminum. Aluminum parts are much bigger, or thicker than a steel one that might replace it. Look at an aluminum connecting rod next to a steel one. The aluminum one is much thicker than the steel rod. I would bet under the same conditions, the aluminum would break before the steel would, even though it is bigger. Stress will take its toll on aluminum at a much lower point than it would on steel. If its calling for 1/2" steel, maybe 1" thick aluminum would be an equivelent. I'm not a metalurgist, so don't take my word as gospel. Just an idea.

i get all my metal from big shops... you would be amazed what they consider to be scrap.

the reason the bracket is 1/2" is to center the caliper carrier over the rotor. Not specifically for strength.

I have all the parts put together for a C5 brake swap. And the brackets are that thick to align the caliper properly. Plus, they are not very big so they are not very heavy. If you are replacing old iron calipers, you will save weight by using the aluminum calipers and the steel brackets...Just my $.02

IT's all in the thickness...
 

(and its extremely difficult to cut PLATE that size scott...) Around here, you buy flatbar by the 20' stick. Cost is pretty expensive. Then, you have to transport it, trailer or pipe rack (No, a pick-up won't work...). Then you cut it to blank size (2" X 6" right?). Cutting it with a cut-off saw is about ideal (no- torches, thats HACK). Then, you center the hole to be drilled in this 1/2" thick blank. Drilling holes in this thick of steel KILLS bits (3/8" holes?). In other words, you'll burn through a few bits making a couple sets. I figure, run a 1/4 inch pilot, finish it off with a cobalt 3/8 bit. Even my titanium bits get burnt drilling lighter material (3/8" thick). THEN comes the REAL challenge, milling the steel into the specified shape. Can't cut curves with a cut-off saw. If you had a plasma cutter that would work (although you'd need a guide face). As usaul, a torch would be far too sloppy, and my Band saw would go through one blade for every blank at least (it's a big saw). If you had a laser cutter of some sort, Good for you, the average shop doesn't. Yeah, you could send the blanks off and have them cut, but that is expensive and uneccessary. If the offset could be accomplished with spacers, thinner material could be used VERY effectively (1/4" thick is PLENTY). ALuminum WOULD work, it would be easier to cut, drill and transport. BUT, you also have to remember that the aluminum in question is about the same price per stick as the steel. Using the aluminum has nothing to do with saving weight, it has to do with EASE of manufacture, Steeel does not lend itself (not in this thickness for sure) so easily. If I had a plasma cutter lying around, I'd gladly make them from steel, If someone brings me a few feet of the steel bar, I'd even cut the blanks for them (they'd have to pay me to drill them though, bit's are expensive). As for the profile shape.....It just looks like aesthetics to me but, if someone could generate a template without cuves, I"D make them for you (Scott...). I'm amazed at how much money people spend for such pices, that don't haev mechanical function (I heard 60 a pair to cut them with a laser?). Try and remember that calipers are held on by two 1/4" or so bolts with about 7 threads. A bar of aluminum of the size in question is SUBSTANTIALLY stronger.
Talk about an Essay!

Re: IT's all in the thickness...
 

Like mentioned above, I'm sure I can find "scrap" or "surplus" steel that would be fairly cheap. I know aluminum would be a lot easier to cut and possibly cheaper, but thats not what I'm concerned about. I dont want to die :) a plasma cutter probably isnt the best tool to make the cuts through half inch thick material is it? Especailly brake brackets since heating the material THAT much could cause some loss of strength. I believe the curves in the bracket are necassary for clearnace with certain parts of the caliper and so it will fit correctly on the spindle, but I'm not 100% sure. I need to get my hands on a piece of .500" MDF so I can make a template so I can test fit all this stuff before spending money or the final brackets.

Re: Re: IT's all in the thickness...
 

its the 2nd most ideal tool.... right after laser cutter but before a mill...

A'ight, just showing my ignorange when it comes to metal work... What about water jet cutting? I'd think that'd be even better than laser, wouldnt it?

If you
 

have access to a water jet....... I don't know their limitations (seen em cut 1/4" titanium though). I wouldn't want to use a mill either, it would take forever. The water jet is pretty cool though. As for laser, I'm pretty sure they can cut that thickness, it just costs a bit (have to program the CNC).

Do you want the aluminum so you can polish it up and make it look nice or is it the weight saving?

One guy said "no" to stainless. Why won't stainless steel work in this application?

I've heard the same thing about aluminum roller rockers (that they aren't as durable). There is a company (it might be Competition Cams) that has ss rockers that, they claim, are as light as the aluminum. So, I'm just wondering why stainless won't work since it can be polished to a nice finish.

LOL. I dont necessarily WANT aluminum. I was just asking if it had the properties necessary for something like a brake bracket. Not for looks, polishing, weight, etc. I dont know the properties of stainless compared to other types of steel, so thats why I said it probably wasnt the best. Anyone know?

Scott

Simply put the question is; are willing to risk your life? The last thing I want to happen is slam on the brakes for an emergency stop and have a caliper mounting bracket snap. Yes it is possible to make a aluminum bracket that will handle the load and probably not brake but if you don’t have a degree in material science then don’t mess with it. Brake parts are subject to a lot of heating and cooling while under stress this just fatigues aluminum and it will eventually brake if not engineered right.

Just use steal, you don’t want to end up getting a Darwin’s award.

one other "Problem" with alluminum is chosing an appropriate alloy. You can't just use what you find lying around. There are many variations from 1100 pure alluminum to high tensil aerospace alloys. i don't know which one to use, they all have different properties.

Hey Scott,

What are you trying to do here? Are you going for weight savings, possible show quality finish, ease of manufacture, or are you just curious about options???

I have no intentions of rereading the entire post at this point so a quick answer may help all of. I too am doing the C5 brake upgrade, but I already have steel brackets made up...

Later...

I was just wondering if it was possible to safely use aluminum for the bracket material, since I had been told that it would be OK. I have decided to not use aluminum, and will be going with steel brackets when I get around to making them.

Re: C5 Brake swap brackets, aluminum instead of steel?
 

Came across this whilst reading old threads. Thought I would offer my experience since all that was posted in here was theoretical or conjecture. I ran the LS1 Front brake setup for one full year including the AutoCross season. I made my mounting brackets out of aluminum. After the year of use I moved up to the Wilwood FSLs and 13 rotor. When I took them off I looked them over and could see nothing physically different about them. I slipped the same drill bit into the bolt holes I used to drill them and noticed 0 elongation. The brackets were still a mirror of the template I used to cut/drill them. The brackets were still flat against a straight edge.
[IMG]http://i774.photobucket.com/albums/y...psbdb652d6.jpg[/IMG]
Perhaps it can still be said/argued that you wouldn't notice anything physically different about them until they suddenly snapped, but I tend to think that it would take something extraordinarily violent for that to occur. Maybe repetitive hard braking from 80+mph as a road course would give could do something to them, or maybe tens of thousands of daily driving braking would do something. But as it stands, one season of nice weather driving and AutoCross did not seem to harm them.

Re: C5 Brake swap brackets, aluminum instead of steel?
 

Critical parts such as K-members, A-arms, spindles/uprights etc are commonly made from aluminum. They also undergo exhaustive FEA and endurance testing prior to being built. Failure of any of these at any time would have catastrophic results. Is that risk worthwhile to save a few ounces on a part you chewed out of your garage?