Need Your Input on G2C Conversion, Please

brianj5600 · Aug 20, 2006

Very nice! I want 15" wheels someday, so I am keeping small rotors. The Mach1 wheels were cheap and will do for now.

Sundance · Aug 20, 2006

Steve, If you need to pull the caliper inward but can't machine the adaptor you can mill the caliper bracket a good 1/2".

When I adapted Cobra brakes to a MII spindle that is what I had to do. What I ended up with was Granada rotors turned down to make hubs. I used the factory wheel mounting surface and placed the rotor on that. No need for centering rings. I mounted the adaptor using the same locations as the stock caliper mount. Because I went to the outside instead of the inside I had to machine the cobra caliper mounts to alight laterally with the rotors.

Differant application but, that is what I did. Hope it helps some.

Jester67 · Aug 21, 2006

What would the cost be if machined out of steel instead of aluminum I would think that once the CNC program is created the chose of materials would be easy. As mentioned above by others I am also not a fan of aluminum for this application. While I do agree that ultimate strength is what it is, the characteristics of materials vary and it is this variation that makes all the difference.

1320stang · Aug 21, 2006

Well, the steel piece would be thinner, the cost of materials should be cheaper, but cutter head wear would be increased. I'd think a steel piece would be cheaper, but it shouldn't be more.

bnickel · Aug 21, 2006

ultrastang said:
It actually goes back a year earlier than that. 1968 was the first year the disc brake equipped Mustangs switched from the K/H 4-piston fixed-mount caliper to a single large piston floating caliper.

I'm pretty certain the '68-'73 mounting points on the spindles are the same on the '68-'73 disc brake spindles as the mounting points on the '75-'80 Granada/Monarch & '74-'77 Maverick/Comet spindles.

However, --for me, I'm staying away from the pre-'70 model spindles with their thinner spindle pins. I can't keep someone from putting the adapter brackets on a '68/'69 disc brake spindle. All I can say is you've been warned. I'm more interested in a safer assembly than turning a fast buck. I don't make a big income at my job, but I'm not so desperate for money that I would push this conversion off on someone with a spindle that's really not up to the task.

All Mustang spindles (drum or disc brake) from '64½-1969, have a thinner, weaker design than the '70-73 drum or disc brake spindles. In 1970, Ford beefed the spindles up on both drum and disc brake equipped models, because the spindle pins of the pre-'70 Mustangs have a weaker design that can break off at the upright/steering arm.

In a street application, the '64½-'69 spindles MAY run without incident. If you are racing opentrack though, it will just be a matter of time before disaster strikes. --So to me, I just prefer to stay away from them and not chance it either way.

In ANY case, whatever you have or setup you're running, if your spindles are used, take them to a machine shop and have them magnaflux-checked for stress cracks prior to putting the new brake system on.

I wouldn't mind making an adapter bracket for a '70-'73 drum brake spindle. What year model is the drum spindle you have?

www.ultrastang.com

right now i have stock disc spindle on my 69 GT coupe but i'm getting the car ready to sell and won't be doing fancy brakes for it. the next car i get is going to be a 69 cougar that a buddy of mine has but it has MANUAL drum brakes that absolutely have to go. it's really kind of wierd since the car also power steering and ac and the brakes are original to the car, in fact everything on the car is original, it only has 60,000 miles. i want to keep a stock look to the car so that's why i want to keep it to 15" wheels. i can pick up a set of 70 drum spindles from another buddy of mine but this will be a street cruiser 99.5% of the time so i'm not worried about absolute strength i just want some GOOD brakes instead of the drums. i already have a spare set of 69 drum spindles that i was going to use so i could keep the original stuff for later on if i ever decide to put the car back stock.

so for simplicity and to keep the wheels no bigger than 15" i would prefer to stay with an 11" or possibly a 12" rotor, if it will fit, with a PBR caliper that doesn't cost a grand or more. i think i've pretty much decided that i'm going to go with a crown vic rear setup but with a vented rotor instead of the stock non-vented ones or i'll stay with stock drums in the rear. i recently got a really good deal on a tcp rack and i have a set of opentracker roller perches and a 1" front and 3/4" rear sway bars for it already and it will definitely need some much better brakes with the added handling ability.

DarkBuddha · Aug 22, 2006

Nice looking brackets Steve! You know I'm interested, but only if it will allow me to continue to use my '70 disc brake spindle. As Bryan said, shouldn't your bracket also work on '70-'73 disc spindles as well?

Let me know...

ultrastang · Aug 22, 2006

DarkBuddha said:
Nice looking brackets Steve! You know I'm interested, but only if it will allow me to continue to use my '70 disc brake spindle. As Bryan said, shouldn't your bracket also work on '70-'73 disc spindles as well?

Let me know...

I don't have a '70 disc brake spindle on hand to compare, but I'm about 99-44/100% sure the mounting points on the '70-'73 spindles are the same as on the '75-'80 Granada/Monarch and '74-'77 Maveric/Comet spindles.

I've had fairly good input from the early Mustang owners saying they would like to have a set of these conversion brackets, but I've actually gotten more positive responses from the Maverick/Comet crowd on this conversion.
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Jester67
"What would the cost be if machined out of steel instead of aluminum I would think that once the CNC program is created the chose of materials would be easy. As mentioned above by others I am also not a fan of aluminum for this application. While I do agree that ultimate strength is what it is, the characteristics of materials vary and it is this variation that makes all the difference."
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Once the bracket file is loaded in the the CNC milling machine, the machine will cut the brackets out of whatever...aluminum, steel, stainless, inconel, titanium, unobtainuim, whatever...

Aside from the cost of the type of material you are having machined, you are also being charged by the hour. Not only is metal harder on mlling/cutting bits, but it takes longer to machine. Longer machining times equals higher production costs.

The machine shop's main function (where I had these brackets made), is to produce rocket and missile parts for the defense industry (Lockheed-Martin, Raytheon, Aerojet, General Dynamics, etc). Many of these parts are made out of the same aluminum I had these brackets made from. The MIL-specs on these parts demand materials with extremely high strength to weight ratios. 6061-T6 & 7075-T6 aluminum is used extensively in the defense, aircraft and areospace industry. Some of the things this aluminum is used for is rocket motor/missle casings, fins, cone sections, aircraft structures and even sprockets for ATVs.

A missle or rocket is an item that's only used one time, but something like a 747 jumbo jet is something that's extremely heavy and has lots of stresses and strains put on it during it's life span. If the aluminum was a major hazzard, you probably wouldn't find it used as the main component that holds a jet airliner together.

Sundance · Aug 23, 2006

My only arguement for aluminum vs. steel, and a point that thus far has not been mentioned, is fatigue cycles. Without that consideration I would agree that the strength would be the same.

brianj5600 · Aug 23, 2006

Is there a company making steel brackets? I have only seen a couple brackets and they look like Aluminum.

LMan · Aug 23, 2006

nice bracketry, Brian...lot purtier than mine

Are you using the stock (11") rotor?

Steve, I'd be on this like a Ethiopean on a BigMac if you could use 15" wheels...

Jester67 · Aug 23, 2006

Sundance said:
My only arguement for aluminum vs. steel, and a point that thus far has not been mentioned, is fatigue cycles. Without that consideration I would agree that the strength would be the same.

Fatigue cycle is one of the properties that I was referring to as well as corrosion and temperature cycling all of these. As far as the use of aluminum on jets and other applications, I agree it is the best material for the application but I am willing to bet that the brake hardware is steel.

brianj5600 · Aug 23, 2006

LMan, I have Granada rotors from Degins. What MC are you using?

Has a Corvette been built in the last 23 years with that did not use aluminum for spindle and control arms. I think there is plenty of meat on G2C brackets.

ultrastang · Aug 23, 2006

brianj5600 said:
LMan, I have Granada rotors from Degins. What MC are you using?

Has a Corvette been built in the last 23 years with that did not use aluminum for spindle and control arms. I think there is plenty of meat on G2C brackets.

I'm still sorting out some details and haven't plunked the money down to have a batch of brackets made, yet. I could have them made out of steel, but I haven't talked it over with the guys at the machine shop to see what steel brackets would cost vs. structural aluminum.

As I've mentioned, aside from the cost of the material being milled, cost is also based on the time it takes to make the component. The aluminum brackets I have took about an hour each to machine out. Steel would take longer, since cutting rates have to be slower with steel. --I'm sure they would also pass along the cost of the milling bits to me as well, since steel is a lot harder on milling/cutting bits.

If they do end up being machined out of steel, it just means I'll have the only aluminum set of G2C brackets. --but you know that the designer always has to have the fancier components over what the consumer gets.

www.ultrastang.com

LMan · Sep 5, 2006

brianj5600 said:
LMan, I have Granada rotors from Degins. What MC are you using?

Stock '67 disc/drum + booster. Works like a charm.

69gmachine · Sep 5, 2006

The mounting points are indeed in the same place, however, the 70-73 spindle uses a 9/16" bolt in the upright whereas the Granada spindle uses a 1/2" bolt. When I originally did the Granada conversion, I drilled out the upper hole to 9/16" and installed caliper brackets (and calipers) from a '71 'stang in order to make them appear original.

I am currently using a welded bracket that I made myself to fit C5 'vette PBR calipers that are located off the original lower mounting hole. This allows for a 12.125 x 1.25 rotor. These thick rotors can handle a lot of heat without cracking. The hubs are aluminum Wilwood units. The rotors are made by Coleman racing, and can be easily removed from the hub at the track, without pulling the hub.

I would be interested in your bracket, but I want to retain my C5 calipers. The mounting points are the same, but I'd like to use a larger rotor since I'm alraedy running 17" wheels. I don't need the centering hub.

Need Your Input on G2C Conversion, Please

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