FAQ Brake Questions© by Dean S. Oshiro

Zero Offset™ Brake Kits

Frequent Asked Brake Questions© by Dean S. Oshiro

"Frequent Asked Brake Questions"© was written as a quick reference on Brake questions. Hopefully this will make it easier for you to answer the questions you have. The in text links will take you to the Brake Article© I wrote. The links in the upper right side bar are links within this page. Lower right side bar links take you to another page. Please take the time to read the Brake Article©. It has been read, down loaded, copied and counterfeited by many people. I am sure that it has saved someone's life. I have only changed some wordage from the original article. © 1994 to 2015 Dean S. Oshiro

FAQ© by Dean S. Oshiro

Question: I have a fairly large cam and no brakes I saw a product on shade tree mechanic about two summers ago about a electric vacuum pump can some tell me where I can get one and the name of it?
Answer:Waste of time and money. Having a large camshaft is common in hotrods. Most of the power booster require 16-18 inches of vacuum to operate. The electric vacuum pump and vacuum canister cost between $350 and $450 depending on where you buy it.
Our Solution: We use the Gorilla Performance™ dual master cylinders that have an output of over 1,400 psi. This is the same technology that has been used for over 40 years. No power booster is required, no proportional valve and no residual valves on disc brake applications. Also allows for additional room for your brake system uses stock pedal and it is 100% mechanical so there is less things to fail.

Question: I see that Wilwood is now coating the rotors black, why not zinc?
Answer: I have mix feelings about the new "black" rotors, they say the black coating improve break-in time on the new rotors with a break in distance of about 30 miles. After that the rotors will be same as a seasoned zinc rotor. Zinc rotors are available as an option add $70 per kit. Or special slotted rotors can be purchased when you order.

Question: Does this brake kit include everything I need?
Answer: It includes everything for both front spindles, everything from bearings and seals to rotors and calipers. The kit will have new bearings, seals, rotors, rotor adapters, vented rotors, aluminum calipers, anodized black aluminum caliper brackets, disc brake pads, billet aluminum hubs, aluminum dust caps, 1.75" studs and all necessary hardware for you to install this kit on your stock spindles. You will need to replace your master cylinder if you currently have a drum/drum application. Master cylinder run between $50-$200 depending on application. You will also need a proportional valve and DOT approved stainless steel flexible brake lines. The brake lies are free with our front brake kits. We will provide you with 16" or 18" brake lines, 1/8NPT x -3 straight for the caliper, 3/8IF x -3 or 10mm IF x -3 and frame clips for the adapter to the frame. Some applications require a 45 degree or 90 degree these parts are available at your local parts store from Earl's, Aeroquip or Russell. If your car requires different length hoses or adapters we will gladly exchange them but, you will only have to pay for the shipping charges.

Question: How quickly can I get this shipped?
Answer: Normal delivery is 2 to 3 weeks. We do not stock any brake kits and all of the rear kits are specially made for us and not available through other Wilwood dealers. For this inconvenience of having to wait, we offer you free shipping, free brake lines and emergency brake cables. This value can range from $125 to $500. Items other then the brake kit will be shipped from our Washington warehouse. You can request expedited service for a fee of $40 per brake kit and your order will be expedited and shipped within 2-5 days. Please remember you are ordering from the person that wrote the brake article, which will be able to assist you with technical questions and not a person looking your part up on a computer that does not know the why's and why not's. International, Hawaii and Alaska shipments are shipped USPS, DB Schenker or any other carrier you choose.

Question: What is the biggest rotor I can use?
Answer: As a rule of thumb you will need subtract 4 inches from your wheel size. Cars prior to 1968 have steel wheels not designed for disc brake calipers, most of these cars used 9" or 10" drum brakes with 14" or 15" rims. These early wheel had the centers welded to the rim behind face of the hub (where your wheel bolts on) new wheels are welded so it is in front of the hub. If you are using early wheels or wheels made this way you will have to use the 4" clearance rule.
10.75" rotor - 14"+ wheels;
11.00" rotor - 15"+ wheels;
11.75" rotor - 15"+ aluminum wheels;
12.19" rotor - 16"+ aluminum wheels:
12.90" rotor - 17"+ aluminum wheels;
Rotors can be ordered plain, slotted (gas vented), drilled and slotted, floating mount, balanced and stress relived.

Question: What type of flexible brake lines do I get with my kit?
Answer: We provide free DOT approved stainless flexible brake lines. DOT approved lines have a band over the crimped fitting to prevent failure. Brake lines tend to fail when the force from surging works the joint loose. Do not use lines that are not DOT approved on the street.

Question: Will I have to buy spindles to use this kit?
Answer: No, the ZO1 brake kits they are designed to use the stock spindle. The caliper bracket will generally not work with drop spindle unless they maintain the same configuration as the stock spindle. Most Mustang II drop spindles will work with the front brake kits, the mounting of the caliper is the same as stock. Sometimes there will need to be modification to the spindle, this generally will entail drilling out a hole to larger size or minor grinding in a non-structural area. For additional information installation please feel free to down load the instructions by typing www.hotrodheaven.com/store/brakes/pdf/ then add the Wilwood part number after the pdf/. Example: The Camaro kit uses a 140-2285 (140-2285b is the same) just type 140-2285.pdf, so the url would be www.hotrodheaven.com/store/brakes/pdf/140-2285.pdf Some of our Zero Offset™ Brake Kit for the Early Mustang requires the 71-73 disc brake spindles only because the drum brake spindles does not have the correct mounting holes to push the bracket 1" further inward.

The new ZZ1 and ZR1 kits include spindles and custom hubs that keep the wheels inboard.

Question: What is a "Zero Offset™ Brake Kit"?
Answer: Our Zero Offset™ Brake Kits are special kits we have designed using quality parts and our custom bracket. Most brackets are mounted to the face of the spindle, our Zero Offset™ Brake brackets are mounted behind the face of the spindle, which allows the hub at stock or slightly behind stock location. The benefit is you will not have to buy special offset wheels and you can retain the same turning radius as stock and the hot rod reverse rim look. The higher cost of the Zero Offset™ brake kits is, because we have to purchase individual parts, which is higher than in a kit.

These kits are now offered in the original verision using stock spindles called ZO1 or the new ZZ1 or ZR1 kits which come with custom spindles. Then newer ZZ1 and ZR1 kits use bigger bearings and are about 0.75" to 1" shorter than the Wilwood hubs in the ZO1 kits.

Question: Is this kit for racing only and DOT approved?
Answer: There is not such thing as a DOT approved after market brake kit. No manufacturer or vendor will give you a written letter with that certification on it. The big difference Wilwood states that these are for racing only to limit their liability. Wilwood is one of the few companies that make brake kits for the Winston Cup Cars. No manufacturer will provide you will a DOT certification in writing. Why? Because there is no such thing, just ask Baer, Gobal West or Stainless Steel Brakes to provide you with this certification in writing.

The heavy duty kit is designed for both street and racing application. Vented rotors are used on applications over 2,000 pounds. The front rotors are usually 10.75" to accommodate smaller diameter tires and to clear your stock steering arms and A-Arms. Rear rotors are 12.19" as there are no steering components involved. The heavy duty kits have use a .810" thick rotor, which is more efficient then OEM 1" rotor. OEM rotors have the hub incorporated in the design to save money (they can be cast one piece). The separate rotor displaces the heat evenly and more efficiently. Our custom brake kits can be order with any size rotor/caliper combination.

Question: What does DOT approved mean?
Answer: There is no such thing as DOT (Department of Transportation) approved brake kits. They do not certify or approve components. When a brake manufacturer or seller claims their product is "DOT approved", the claim is false.
The only components regulated by DOT are: 1. Brake hoses 2. Brake fluid 3. Tires 4. Exterior Lamps
(A manufacturer using the DOT symbol on the above products signifies that the manufacturer has "self certified" that the product meets FMVSS standards) New vehicles must comply with certain government standards. The controlling document for standards is the "Federal Motor Vehicle Safety Standard", or FMVSS. Brake performance is covered under FMVSS sections 105 and 135. Vehicle manufacturers certify, either through self-certification or independent certification, that their vehicles comply with the standards. Brake components, like many other vehicle components, are generally the way they are as a result of performance, cost, manufacturer preference, and sometimes, tradition! Materials, features (anti-rattle, anti-squeal, dust boots, fixed mount, sliding mount, piston count, etc.) and finish are not dictated by DOT

Question: What bolt pattern does this brake kit have?
Answer: Most of our 5 lug front kits are dual drilled with 4.5" and 4.75" bolt patterns. All the 4 lug kits are specific to the car the kit is made for. The kit will come with 1.75" studs with optional 3" studs to meet NHRA specs. The rear kits are drill 4.5", 4.75" and 5". GM cars with 7/16" rear wheel studs will be required to install 1/2" studs to index the rotor hat.

Question: Can I upgrade?
Answer: Of course you can. You can upgrade to any other option such as floating rotors, zinc rotors, drilled rotors, thermo pistons and color or polished calipers.

Question: My application does not show for sale, do you have other kits?
Answer: Yes, we have all the kits from several brake manufactures and we also make special brackets for other applications using quality components.

Question: Do we offer the rear disc brake kit with an emergency brake?
Answer: We offer to types one with a mechanical caliper and the newer e-brake kit with internal shoes just like the Corvette and Ford Explorer. Our rear e-brake kits come with free emergency brake cables.

Question: What cable do I need to use when installing the rear disc brake kit with parking brakes?
Answer: We give you a emergency cable kit that is a "cut to fit".

Question: Do you have a kit for my 63-64 Corvette?
Answer: Yes, we have custom 11.75", 12.19" and a 12.90" rotor kit for the front with DynaPro6, Forged Superlite and Superlite 6 piston calipers and 13" and 14" kit using the W6 calipers. Our kits does not move the wheels out in front. I also have a kit for the rear of the 63-82, 84-87 and 88-96 Corvettes. The DP6 calipers will work with stock knock off wheels.

Question: Is it safe to use steel wheels with these brakes?
Answer: We offers a shield part number 300-7500 for use with steel wheels. Cost is less then $15. each.

Question: What is a green bearing with snap ring?
Answer: The term "green bearing" comes from the "Green Bearing Company". All the older Mopar's and Dana rear ends had a spacer in between the axles and was pre-loaded from the passenger side. All the green bearing does is converts the rear housing to a "retainer" type where a retainer is used to hold the axle in place. This is common on GM & FMC housings. You should be able to purchase the green bearing from your local bearing supplier in your city. The part number is ST400. If you still can not find this bearing would be glad to purchase it and send it to you.

Question: My 58 Vette, has been completely rebuilt including the braking system. On hot days when I start out I might have3-4 inches of slack on my brake pedal until pressure becomes apparent. As the car and the day heat up I find less slack in my pedal until finally there is none and the passenger rear will start to drag. Could silicone help?
Answer: You have probably have a drum brake master cylinder with disc brakes, or a defective built in residual valve in the drum brake master cylinder if you still have your drum brakes. When you reapply the brakes the brake fluid will not flow back into the master cylinder. You can also go to our tech section and find additional answers. Silicon brake fluid will not help you and should be used only under certain conditions.

Question: Should I use Silicon brake fluid?
Answer: Only under certain conditions. DOT 3 would be better. Never use silicon brake fluid in a street or race car. It compresses. This was made for trailer queens.

Question: Want to change to disc brakes on my 55 Chev, I understand there is a kit that uses GM rotors.
Answer: Yes, there are numerous kits available that use the GM rotor and caliper. They sell for $300 to $750 depending on who you buy it from. They generally use 70-77 Chevelle rotors and calipers with a fabricated steel bracket. You will need to convert your master cylinder and use a power booster with this system.
Our Solution: Buy one of our disc brake kit. It offers you the billet aluminum hubs and separate rotor which not only is good looking, it displaces the heat and will out perform the cast iron setup. The 4 piston calipers also requires less volume and less pressure. The additional cost for the best is less than $300 more.

Question: I have a hard pedal and even with a booster it takes a lot of pressure to apply the brakes.
Answer: You have one of three things wrong. 1. The pedal ratio is wrong, this seems to be the number one cause. 2. You have a 1-1/8" master cylinder and with the pedal you are using it is causing you to apply additional pressure. 3. You do not have any vacuum so the power booster is not working anyway.
Our Solution: Use the Bal-Bar™ dual master cylinder set up. Race cars have been using them for over 40 years. This is tried and proven. Or buy using the 4 piston design calipers which require less volume so you can use a smaller bore master cylinder for higher output pressure.

Question: What size booster can I use on my car?
Answer: In this case you want the bigger the better, especially if you are running a big cam. Big cams = low vacuum. But, if you use to big of a booster and to small of a master cylinder you will have to much brakes. So depending on the amount of vacuum your motor can pull will determine the booster size and master cylinder. I would recommend dual diaphragms with low vacuum. Little or no vacuum forget it, just stick with a manual system. To determine the size that will fit on your fire wall just cut out some circles with the diameter you are shooting for. Place them on your fire wall and see which ones you can get your valve covers off. The last thing you want is to have to remove the master cylinder to take your valve covers off. Consult your brake person on the volume requirements of your calipers. OEM calipers use large amounts of brake fluid. If you do not have enough vacuum see dual master cylinders.

Question: Why does Chevrolet tip the master cylinder up when using a booster?
Answer: GM uses two (2) holes on the pedal to control the pedal ratio. The lower hole is used for power booster and lowers the pedal ratio. In order to properly align the booster rod, GM uses an angle bracket on the booster so that it will point to the lower hole. Failure to keep this alignment will result in booster damage. The Ford engineers did it right by using two different pedals.

Question: Should I run 1/4" lines on my car?
Answer: In most cases no, there is no advantage to use 1/4" line in a standard passenger car. Once the brake line is filled it has the same efficiency. Friction lost or if you are using a Cool-Flow™ recycling system you will benefit by less friction lost and increased fluid volume.

Question: Do I need a stock combination valve or just an adjustable proportional valve? I asked this guy on a forum and he is dead set on using a comb valve. This is what he writes, "With no combo valve & an adjustable proportioning valve you only get front/rear proportioning. You lose metering. Without the metering valve you can have heavy nose dive under braking, early/excessive front tire lockup & increased front pad wear"
Answer: A combination valve is basically a brass block with a built in pressure switch, 2 holes coming in from the master cylinder and 3 holes going out. The pressure switch is not required. The front part of the valving only acts as a Tee fitting. The rear valving is 3/16 hole coming in and about 1/8" going out. They are basically reducing the size of the hole of for metering the rear brakes. Since these are made "universal" they are over metering the rear braking so that this valve can be used on all applications. I.E. bucket T vs Lincoln. The factory makes a specific combination (metering block) for each car, they even make different ones between same models with different engines. Now how can you install a "universal" combination valve and expect it to work on all applications? By installing a adjust proportional valve, you have full control of your balance without over metering it. This balance will chance just by changing tire sizes or weight distribution. My opinion is throw the comb valve away, unless it came from the 'factory" (engineered for your car) and you have not made any changes to your car (i.e. tires, motor, suspension & brakes). To many people try to be engineers that are not. Ask yourself has physics and math changed lately? Here is a link Proportional Valves.

Question: Do I need a distribution block for my master cylinder?
Answer: No. Distribution blocks were designed for factory cars to meet a specific need for a specific car. Each car from the factory has different weight distribution, braking characteristics and tires. Think of it this way, "did GM make one distribution block for every single car they built?" If the answer is no, how can you buy a distribution block made for "universal" application? Waste of money! Just buy an adjustable proportional valve and route it inline on the rear brakes.

Question: Why is a residual and proportional valves needed?
Answer: Residual valves retain a specific pressure in the brake lines. On drum brake application it is needed to apply pressure on the cup seals in the wheel cylinders. It is important you understand master cylinders and which M/C's have residual valves built in and why. Proportional valves balance the braking system generally front to rear.

Sometime in the near future you will no longer have to worry about contamination of brake fluid. The Cool-Flow™ System will someday be mandated on all vehicles. This is our answer to reducing the temperature of the rotors and thereby control tire pressure in the middle of a race. The Cool-Flow™ System will revolutionize the way we thing about brake systems.

This was republished to update you on Brake Systems. There is two things that will never change physics and math. Nobody can redesign a brake system and change physics and math, you can not reinvent the wheel. If anyone can prove to you anything in this Brake Article© with a formula, then they are correct. Engineers have been reading this Brake Article© since 1994. I can always tell an engineer, they ask black and white questions. They want a black and white answer. I hope someday reading this might save someone's life.

The Brake Article© by Dean S. Oshiro

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