I've searched and read through a ton of posts and just wanted to run something by you all.

First i've got the body off of my 71 and will be building the chassis first. I have a set of B body spindles and 1LE 12" rotors up front. My question is about off the shelf caliper options. I've been told to run stock Chevelle Disc calipers, as well as B body Caprice calipers (the ones that had the 12" rotors, not the 11"), as well as using the 90'ish camaro calipers which the 1LE rotors came off of. Will all of these work? Or is one more suited for the 12" rotors?

I just want to make sure i buy the appropriate calipers intended for a 12" rotor. I say that because i assume there is a difference between the calipers intended for an 11" rotor vs. a 12" rotor.

Thank,
Kyle

The calipers are the same. Use the calipers off of the Chevelle.

I used Calipers from a 70 Chevelle and hoses from a 72 Caprice and this combination worked well when using the stock drum brake hose frame brackets. I never tried Chevelle hoses but have read that they were slightly shorter and didn't work with the drum brake hose frame brackets.

Peter

I just found out that the Camaro 1LE calipers are dual piston. That sounds all the much better to me. Any chance that these will fit just fine?

Thanks
Kyle

Not likely. The mountings is probably different.

Peter

Thanks a bunch...

Kyle

If you would like to move away from the stock caliper and upgrade, you can try the Wilwood GM III caliper. This is a bolt-on replacement for the stock caliper. It is aluminum, features a triple bridge, and is extremely rigid. Remember, calipers are essentially sophisticated hydraulic clamps, and any spread at all is undesirable. There is a big difference in braking with a premium caliper. Merely being able to lock the wheels does not mean that the caliper is doing its job.
The GM III widely used by racers. It has practically no caliper spread under severe braking, cools very quickly, and easily accepts any type of stainless braided line you care to use. It is extremely light compared to the stock iron calipers.

They are fully rebuildable, and use a 1/8-27 NPT inlet.

It is also fairly inexpensive. You can get them from Stock Car Products, or a supplier like them, for under a hundred each (last time I bought some I paid $94). I run them on my Camaro canyon racer, and they are very good in modulating pressure, and dissapating heat.

http://i20.photobucket.com/albums/b203/aero80/gm3sa.jpg

That sounds like a very good option. Do you think there is a better stopping with these calipers or is it more of a lightness factor?

As for stopping power does anyone know of a 4 piston caliper that is fairly bolt on when using B body tall spindles and using 12" 1LE rotors? I just assume no since i haven't heard a lot about it.....unless i'm researching the wrong places.

Thanks,
Kyle

There are many advantages to the racing aluminum caliper, and for the the GM III in particular. There are similar offerings in the circle track industry, and you can easily check them out on stock car supply websites. I chose the GM III after much study and experience with other brands including Howe and Outlaw. The others are decent parts, but the Wilwood seems to work the best for me.

Due to the heat rejection qualities of the coated aluminum caliper, the fluid remains at a lower temp compared to iron calipers during similar usage, increasing pedal modularity (feel, control, repeatability). For example, much is made of how bigger rotors absorb more heat, but when they do get hot in HP use, they are just holding that much more heat and take longer to cool (as in they are hotter at the next corner or stopping event). They don't get hotter, just the greater mass of steel can contain more heat). It is better to get rid of it than to hold on to it. That is what happens with stock steel calipers- once they heat up, they become a real detriment to braking performance because they cannot cool down quickly.

The stiffness of a well-designed high performance caliper not only increases overall clamping force, but also adds to repeatable stopping power due to reduced distortion in multiple stops or corner work by giving repeatable feedback to the driver, enabling him/her to develop a style that does not depend on constantly adjusting to changing brake performance.
You would be surprised how much a stock caliper spreads (distorts) in heavy duty usage. Just because it is steel does not mean it does not flex or spread. A lot of your pedal power is dissapated by moving metal in severe braking conditions, exacerbated at elevated temps, instead of clamping.

The piston and bore are stainless steel, increasing life span as well as the usual benefits of stability at varying temperatures and resistance to corrosion in daily driven vehicles.

The lighter weight is a major advantage in suspension controllability. When used with aluminum or lightweight steel wheels (I use NASCAR Bassett Inertia Advantage wheels) the difference in suspension performance is enough to require completely different shock valving.

Overall, the stopping power difference mainly shows up during high perfromance driving. In traffic it's a wash, as even rebuilt stock calipers are sufficient to perform in daily commuting and errands. However when it's all on the line and you are using braking power as much as engine power (combining with talent on the brake pedal as much as on the other controls at high speed) the racing design caliper really comes into its own, and at that level it is far above the stocker. Here where serious issues depend upon your equipment being there for you and perform as expected just when you really need it to, the repeatable modularity qualities of a racing caliper give you confidence and safety as well as performance.

Another item to consider: The GM III caliper will fit inside a 15" steel wheel, even with 12" rotors. These pix show a GM III mounted on a 12" rotor B-body spindle (yes the pads are missing in the first pic), and mounted for use inside a 15" NASCAR steel wheel.

http://i20.photobucket.com/albums/b203/aero80/GM3ma.jpg

http://i20.photobucket.com/albums/b203/aero80/GM3mb.jpg

I have the 1LE set up on my 68. The difference I found in stock calipers is the angle the hose is aimed. Some are for a thicker rotor too. I used 70 Chevelle calipers from Advance. I also used a stainless braided hose to fit a 69 Camaro. Two reasons if I remember. Longer and it fit the brackets from a drum car.

There are many advantages to the racing aluminum caliper, and for the the GM III in particular. There are similar offerings in the circle track industry, and you can easily check them out on stock car supply websites. I chose the GM III after much study and experience with other brands including Howe and Outlaw. The others are decent parts, but the Wilwood seems to work the best for me.

Due to the heat rejection qualities of the coated aluminum caliper, the fluid remains at a lower temp compared to iron calipers during similar usage, increasing pedal modularity (feel, control, repeatability). For example, much is made of how bigger rotors absorb more heat, but when they do get hot in HP use, they are just holding that much more heat and take longer to cool (as in they are hotter at the next corner or stopping event). They don't get hotter, just the greater mass of steel can contain more heat). It is better to get rid of it than to hold on to it. That is what happens with stock steel calipers- once they heat up, they become a real detriment to braking performance because they cannot cool down quickly.

The stiffness of a well-designed high performance caliper not only increases overall clamping force, but also adds to repeatable stopping power due to reduced distortion in multiple stops or corner work by giving repeatable feedback to the driver, enabling him/her to develop a style that does not depend on constantly adjusting to changing brake performance.
You would be surprised how much a stock caliper spreads (distorts) in heavy duty usage. Just because it is steel does not mean it does not flex or spread. A lot of your pedal power is dissapated by moving metal in severe braking conditions, exacerbated at elevated temps, instead of clamping.

The piston and bore are stainless steel, increasing life span as well as the usual benefits of stability at varying temperatures and resistance to corrosion in daily driven vehicles.

The lighter weight is a major advantage in suspension controllability. When used with aluminum or lightweight steel wheels (I use NASCAR Bassett Inertia Advantage wheels) the difference in suspension performance is enough to require completely different shock valving.

Overall, the stopping power difference mainly shows up during high perfromance driving. In traffic it's a wash, as even rebuilt stock calipers are sufficient to perform in daily commuting and errands. However when it's all on the line and you are using braking power as much as engine power (combining with talent on the brake pedal as much as on the other controls at high speed) the racing design caliper really comes into its own, and at that level it is far above the stocker. Here where serious issues depend upon your equipment being there for you and perform as expected just when you really need it to, the repeatable modularity qualities of a racing caliper give you confidence and safety as well as performance.

Another item to consider: The GM III caliper will fit inside a 15" steel wheel, even with 12" rotors. These pix show a GM III mounted on a 12" rotor B-body spindle (yes the pads are missing in the first pic), and mounted for use inside a 15" NASCAR steel wheel.

http://i20.photobucket.com/albums/b203/aero80/GM3ma.jpg

http://i20.photobucket.com/albums/b203/aero80/GM3mb.jpg
Well that settles that. If it's that much better of a brake caliper then i can't argue about the price of them and the fact that it's a direct bolt on. That's pretty darn cheap. But i was wondering if you clear something up...based on the fact these capilers are priced the same...is there any benefit for using the 2.75 Piston vs. the 2.38 Piston or vise versa. I just didn't want to fall victim of the "Bigger is Better" scenerio if it's really not.

The 2.38 piston is a good choice if you want to use the anti-rattle clip that the D-52 GM caliper uses to keep the brake pads from clacking. The clip will not fit in the bigger piston.

If you want to use the bigger piston, you can run a 2 lb. valve in the line going to the front brakes. Wilwood and others make them, very common. This will keep the pads against the rotor and they shouldn't make any noise. It also performs the useful function of keeping your pedal from having to take up any distance between pad and rotor surface before braking can begin. Many times disc caliper pistons will actually retract after braking, causing a gap between pad and rotor.

Disc brakes require a bunch more fluid volume than drums, as we know. The same thinking applies to the overall volume of the caliper piston(s) all totalled up. The bigger pistons (or greater total area/volume of multiple piston calipers) will require more fluid movement compared to the smaller pistons, and this may be enough to warrant master cylinder considerations. The Wilwood tech line can give a recommendation for Master Cylinder bore size to move enough fluid without becoming too large (and unresponsive). They are usually pretty helpful.

Also, there is a new version of the GM III that uses the GM D-52 rubber O-ring vibration isolaters in the mounting bolts. I'd choose that one. It may only be available in the 2.38 piston size. You won't lose any real braking perf on the street with this piston, and you can use the anti-rattle clips if you prefer not to use the inline 2 lb. valve.

Otherwise, the GM III uses metal sliders instead of the D-52 rubber rings.

Be sure you notice the fact that I pointed out the GM III uses a 1/8-27 inlet for the hydraulic lines. You cannot use the stock banjo fittings, although this is not anything to get upset about.
There are several postions available on the caliper body to use for fluid inlet. I use the upper and bleed the calipers upside down off the disc (no big deal at all). This allows the braided line to run in a more protected way to the hard line connector on the frame.

I use the solid metal slider version of the GM III, but only because when I bought mine the isolater version had not come out yet. In retro, I would choose the isolater.

Here is a pic of the solid sliders I use on my Z28 canyon racer. One is removed, and the other installed. You can see the sleeves I had machined to fit over the standard D-52 caliper bolts. You will not need these if you choose the isolater version (I don't know what Wilwood calls it, that is my own name for them). Also, this is the rear view of the GM III mounted on a B-body spindle and inside a 15" steel wheel.

http://i20.photobucket.com/albums/b203/aero80/chassisbrakesgm3m.jpg