Brake Upgrade Q's

[Springbok]

I am still new to owning a Cobra so I am still in my "learning" phase. After driving the car and looking where I can make some improvements, one of the areas I am looking at are the brakes. I am still trying to figure out my brake system and where I can make some upgrades without overhauling the entire system. I have some basic questions that I was hoping I could get answered.

First some things I DO know about the brake system.

1. Rear end is an 8.8" Ford rear end. There are many kits available to upgrade, I am looking it the Wilwood options.

2. I currently am not 100% sure what master cylinder I have in the car, there are no visible part numbers or markings.

3. I DO have an electric brake booster, but not sure the brand or model.

4. Front brakes are single piston 1978-Up GM Metric Brake Calipers, a pretty base option. The rotors are 11.25in diameter.

5. The wheels are 15".

6. I am not sure if there is a brake balancer in the system, I am still looking.

Some of my initial questions are...

1. Can I upgrade the rear to disc without changing any other components? If not, what would I need to change?

2. Can I upgrade the front without changing any of the other components? If not, what would I need to change?

3. If I change the front brakes, do I reference the front spindle to look for compatibility and fit?

4. What re some of the basic things I should be looking at in order to upgrade?

I know these are vague questions, I am still a noobie but any bits of info always help. I am trying not to overhaul the entire system if possible, Ideally I can just upgrade the brakes at the wheels and not touch the master cylinder and electronic booster.

I have attached pics to give an idea of what I am working with. Pics are of the master cylinder, rear drum, front brakes and electric brake booster.

Thanks in advance for any tips/info!

[LMH]

Brake components need to be able to work together as an assembly. Best advice I can give is to call a company like Wilwood and talk them about options. You should do the front and rear at the same time using matched components. They can most likely steer you right. You will probably need to know what master cylinder you have and the size of you intend to reuse it.
BTW, I have 12.19" rotors on my Hurricane with 15" wheels. That's about the biggest you can get under the wheel.
Larry

[Springbok]

Originally Posted by LMH

Brake components need to be able to work together as an assembly. Best advice I can give is to call a company like Wilwood and talk them about options. You should do the front and rear at the same time using matched components. They can most likely steer you right. You will probably need to know what master cylinder you have and the size of you intend to reuse it.
BTW, I have 12.19" rotors on my Hurricane with 15" wheels. That's about the biggest you can get under the wheel.
Larry

Awesome, thanks!

[LMH]

Oh yeah, make sure to ask them if their kits add to the track width. Some kits do and you may or may not have the space.
Just an FYI!
Larry

[Springbok]

Originally Posted by LMH

Oh yeah, make sure to ask them if their kits add to the track width. Some kits do and you may or may not have the space.
Just an FYI!
Larry

Can you define what track width is?

[1795]

Track width is from outside edge of one tire to inside edge of the tire on the other side. It is easier to measure it that way than to try to get center to center of the two front or rear tires. It is important because you need to make sure that there will be enough room to fit the tires inside the fenders. On an metal bodied car you can always roll the wheel opening up a little to make more room, not so easy to do on a glass bodied car.

[Springbok]

Originally Posted by 1795

Track width is from outside edge of one tire to inside edge of the tire on the other side. It is easier to measure it that way than to try to get center to center of the two front or rear tires. It is important because you need to make sure that there will be enough room to fit the tires inside the fenders. On an metal bodied car you can always roll the wheel opening up a little to make more room, not so easy to do on a glass bodied car.

Ahh...I am assuming this would be more of a concern in the rear since I would be going from drum to disc and the part spacing could be different.

[1795]

It may be of concern for the front as well, you need to ask the manufacturer as some rotors have different back spacing.

[BruceSnyder]

Contact Gordon Levy (Levy Racing). He's an expert with Wilwood systems.

[LMH]

Gordon did my rear brakes with parking brake.
It looks like you have Mustang II front suspension/spindles, so there's lots of brake kits available. The rear will be a 8.8 disc conversion.
Larry

[Dwight]

I would suggest you flush your brake system first. I did that on a Cobra and it was night and day differences.

It went from slowly stopping to sliding the tires.

Last summer I bought a vacuum bleeder. Takes about thirty minutes to bleed the brakes by myself.

Great must have tool.

Dwight

http://www.ebay.com/itm/OTC-Tools-81...152596&vxp=mtr

[Dwight]

Those 11 1/4" rotors were for a 3500 lb car. Your Cobra weights about 2500 lbs.
If your are not racing you probable have sufficient brakes.

Dwight

[Springbok]

Originally Posted by LMH

Gordon did my rear brakes with parking brake.
It looks like you have Mustang II front suspension/spindles, so there's lots of brake kits available. The rear will be a 8.8 disc conversion.
Larry

Awesome, thanks! that was what I was thinking it was, glad you confirmed it.

[Springbok]

Originally Posted by Dwight

Those 11 1/4" rotors where for a 3500 lb car. Your Cobra weights about 2500 lbs.
If your are not racing you probable have sufficient brakes.

Dwight

I am planning on doing some track days because I want to experience this car to the fullest. The existing brake setup is great for driving around town but not good for much else. They feel just fine as is, but I know that doing laps at speed would put a lot of strain on these.

[joyridin']

On the other Cobra site, there is a thread where somebody installed 6 pot calipers on the front and 4 pot on the rear from Gordon Levy. The rear would be good for you, but you may have to modify the front a bit since you have a M2 front suspension.

Have you ever thought about finding an IRS unit from a Mustang Cobra and installing it in place of the solid rear axle? You can find the 28 spline pretty cheap and it would give you IRS.

[cycleguy55]

The type of braking system will depend upon how much track use you're planning and the speeds you'll be running (autocross vs road racing). I did a similar conversion on my car a year ago. When I bought it in 2014 it had the original 9.25" Mustang II discs on the front and 11" drum brakes on the 9" rear end and was just not going to work for me.

I used a 'universal' kit on the back that works for the various types of Ford 9" rear ends, and I believe it also fits the 8.8" axle. It comes with 3 sets of brackets to fit the different rear ends, and uses the GM 'large calipers' with integral parking brakes and 11" solid surface rotors. The only glitch on the installation was there was interference between the calipers and brackets and the rear sway bar and it's brackets. The solution was to rotate the brackets 180° on the axle ends and use the right caliper on the left and vice versa - this was necessary for keep the bleed screws on the top of the calipers.

The parking brake cables were a bit short, but I was able to extend the 5/16" NF threaded rod on the parking brake lever to engage the cables. It was about 1.5" too short, so I used a section of 5/16" NF bolt plus a coupler I made from some steel tubing - a few minutes of threading it with a tap and it was ready for use. Be aware that you need to use the parking brake regularly on the GM calipers to keep them properly adjusted.

On my MII front end I went with a Wilwood 4 piston setup with 11" solid surface rotors. You will need braided lines to connect to your existing plumbing, plus adapters at both ends (1/8" NPTM to AN -3 for calipers, 3/8" x 24 TPIF to AN -3 adapters with clip groove for hard line connection).

I had a combination valve in the brake system (distribution plus proportioning valve for the rear brakes). I removed the proportioning valve mechanism from the combination valve and installed a manually adjustable proportioning valve in the rear brake lines but, to date, have found no need to dial back the rear brakes. I guess the combination of the GM calipers and wider tires on the rear works well with the 4 piston Wilwood calipers in front, but the adjustable valve is there should I ever need it.

I put speed bleeders in all of the calipers - highly recommended. The Wilwoods have 4 bleed screws, but you only need speed bleeders in the upper pair on each caliper. It took a while to bleed the brakes, especially the rear ones, as I pretty much drained all the brake fluid from the system.

The first few stops on new rotors all around were a bit scary as there is little braking power until you start getting them bedded in. It took 2 or 3 light applications of the brakes before I could feel the brakes getting progressively stronger. Once the bedding process was done it was obvious the new brakes were MUCH stronger than the old brakes. I'm really happy with the results - much better than the old system and well worth the investment.

[Springbok]

Originally Posted by cycleguy55

The type of braking system will depend upon how much track use you're planning and the speeds you'll be running (autocross vs road racing). I did a similar conversion on my car a year ago. When I bought it in 2014 it had the original 9.25" Mustang II discs on the front and 11" drum brakes on the 9" rear end and was just not going to work for me.

I used a 'universal' kit on the back that works for the various types of Ford 9" rear ends, and I believe it also fits the 8.8" axle. It comes with 3 sets of brackets to fit the different rear ends, and uses the GM 'large calipers' with integral parking brakes and 11" solid surface rotors. The only glitch on the installation was there was interference between the calipers and brackets and the rear sway bar and it's brackets. The solution was to rotate the brackets 180° on the axle ends and use the right caliper on the left and vice versa - this was necessary for keep the bleed screws on the top of the calipers.

The parking brake cables were a bit short, but I was able to extend the 5/16" NF threaded rod on the parking brake lever to engage the cables. It was about 1.5" too short, so I used a section of 5/16" NF bolt plus a coupler I made from some steel tubing - a few minutes of threading it with a tap and it was ready for use. Be aware that you need to use the parking brake regularly on the GM calipers to keep them properly adjusted.

On my MII front end I went with a Wilwood 4 piston setup with 11" solid surface rotors. You will need braided lines to connect to your existing plumbing, plus adapters at both ends (1/8" NPTM to AN -3 for calipers, 3/8" x 24 TPIF to AN -3 adapters with clip groove for hard line connection).

I had a combination valve in the brake system (distribution plus proportioning valve for the rear brakes). I removed the proportioning valve mechanism from the combination valve and installed a manually adjustable proportioning valve in the rear brake lines but, to date, have found no need to dial back the rear brakes. I guess the combination of the GM calipers and wider tires on the rear works well with the 4 piston Wilwood calipers in front, but the adjustable valve is there should I ever need it.

I put speed bleeders in all of the calipers - highly recommended. The Wilwoods have 4 bleed screws, but you only need speed bleeders in the upper pair on each caliper. It took a while to bleed the brakes, especially the rear ones, as I pretty much drained all the brake fluid from the system.

The first few stops on new rotors all around were a bit scary as there is little braking power until you start getting them bedded in. It took 2 or 3 light applications of the brakes before I could feel the brakes getting progressively stronger. Once the bedding process was done it was obvious the new brakes were MUCH stronger than the old brakes. I'm really happy with the results - much better than the old system and well worth the investment.

Is there a reason you didn't go with Wilwood all the way around as well as slotted/vented rotors?

[cycleguy55]

Originally Posted by Springbok

Is there a reason you didn't go with Wilwood all the way around as well as slotted/vented rotors?

Reasons? None, it was entirely arbitrary...

On to the reasons.

On the question of Wilwoods all around:

1. the front brakes do most of the heavy lifting and the rears very little, so didn't feel I needed more stopping power than the GM calipers
2. Wilwood uses an internal drum for their parking brakes, my kit uses the same piston and pads as the brakes. My wife and I have internal drum parking brakes on our daily drivers and I'm not a big fan.
3. Wilwoods with integral parking brakes are significantly more $$ than brake kits using the GM calipers. [Note: there are kits with GM 'metric' calipers and others with the so-called 'large' calipers - mine are the latter and the ones I'd recommend]

As to the issue of solid surface vs drilled and/or slotted rotors, I did a lot of reading and research before making the decision. My first inclination was drilled and/or slotted rotors, but the more I read, the more I became convinced drilled and slotted rotors were more for the 'cool look' than for actually providing improved performance. Tire Rack even states "Slotted, drilled or dimpled rotors offered as OEM replacements should not be considered appropriate for high-speed track use."

For purposes of clarity, my rotors are vented, but the brake surfaces are smooth.

Some references:

• https://www.tirerack.com/brakes/tech....jsp?techid=87
• Rotors: Blank vs Cross Drilled vs Slotted and Warping | Automotive Thinker - Discussing the finer points of automobiles

[Springbok]

Originally Posted by cycleguy55

Reasons? None, it was entirely arbitrary...

On to the reasons.

On the question of Wilwoods all around:

1. the front brakes do most of the heavy lifting and the rears very little, so didn't feel I needed more stopping power than the GM calipers
2. Wilwood uses an internal drum for their parking brakes, my kit uses the same piston and pads as the brakes. My wife and I have internal drum parking brakes on our daily drivers and I'm not a big fan.
3. Wilwoods with integral parking brakes are significantly more $$ than brake kits using the GM calipers. [Note: there are kits with GM 'metric' calipers and others with the so-called 'large' calipers - mine are the latter and the ones I'd recommend]

As to the issue of solid surface vs drilled and/or slotted rotors, I did a lot of reading and research before making the decision. My first inclination was drilled and/or slotted rotors, but the more I read, the more I became convinced drilled and slotted rotors were more for the 'cool look' than for actually providing improved performance. Tire Rack even states "Slotted, drilled or dimpled rotors offered as OEM replacements should not be considered appropriate for high-speed track use."

For purposes of clarity, my rotors are vented, but the brake surfaces are smooth.

Some references:

• https://www.tirerack.com/brakes/tech....jsp?techid=87
• Rotors: Blank vs Cross Drilled vs Slotted and Warping | Automotive Thinker - Discussing the finer points of automobiles

Very informative, thank you! Seriously considering not going with vented/slotted rotors.

Knowing me, I would want all matching parts since I tend to obsess over details like that. I would probably go with the Wilwood all the way around if I decided to make the change.

I am pretty mechanically inclined, I am just not a "gear head" yet, but I gotta start somewhere!

[LMH]

Kirkham makes an awesome parking brake that bolts into the Wilwood Dynalite caliper. Kind of replicates the parking brake used on the original cars. Pricey but well made as is everything they make.
Larry