here’s an old expression that goes something like, “You should drive only as fast as you can stop.” There’s a great deal of truth in this saying. However, no matter the quality of the brake system it will only function as well as it matches its usage and its installation.
We are going to walk you through some brake basics and follow along with an installation of a Wilwood Engineering brake package, all the while passing along some brake-wisdom tidbits. Also, nothing replaces the detailed instructions that are provided by Wilwood Disc Brakes and are also available anytime online. Visible in the current photos are a front and a rear Wilwood kit. The Aerolite 6R front kit (PN 140-10641) used with a Wilwood ProSpindle 2-inch drop (PN 830-9807) and a 14-inch-diameter drilled/sotted/vented rotor. (There’s also a standard height spindle, PN 830-10832.) In back The Aerolite 4R rear kit (PN 140-11270) is used with the OE-style parking brake and the 14.25-inch-diameter drilled/slotted/vented rotor. A couple of additional items you will need to have aside from tools will be permanent thread sealer, such as Loctite 271 (red) and Wilwood Hi-Temp 570, DOT3 brake fluid.
However, should you find yourself on your own and need to come up with a brake pedal, keep the following in mind. Pedal ratio is calculated by measuring the straight line distance from the center point of the pedal pivot to the middle of the foot pad (measurement A, photos 4 and 5) and then dividing that number by the distance from the center point of the pedal pivot to the center point of the pushrod attachment location (measurement B, photos 4 and 5). If measurement A is equal to 10 inches and measurement B is equal to 2 inches then the pedal ratio is 5:1 (A divided by B equal pedal ratio).
If your master cylinder is lower or higher than the drum brakes being used, no matter what you have to use a 10-pound (red) RPV inline with these brakes. Why? The springs that retain the drum shoes have enough force to compress your wheel cylinder. As it compresses the wheel cylinder, it will force the brake fluid back into the master cylinder, forcing the driver to perform the unwanted task of “pumping the brakes” before they work.
For disc brakes, it’s much easier. If the calipers are higher than the master cylinder (frame mount master cylinders), we suggest using a 2-pound blue RPV valve. The elevation of the calipers being higher will slowly force the brake fluid from the calipers back to the master cylinder.
Start with hard, panic stops from 45 down to 20 mph. For a car that weighs 3,000-3,500 pounds (which takes into account most pre-1949 hot rods and late-model midsize cars through the mid ’50s) you will want to perform these stops about six to eight times. Another tip: Make sure you have your windows down. Why? After about six to eight hard panic stops you should start smelling brakes. This is good. That means you are saturating the brake system, allowing the calipers, rotors, and brake pads (critical) to get hot. This will help get the binders that hold the brake pad friction together hot and onto the face of the hot rotor. This too is desirable. If they feel as if they’re fading, that too is a good thing. It means you are saturating the system. Once you start smelling the brakes you will want to perform two more hard (panic) stops from 45 to 0 mph. This will ensure we have fully saturated the brake system.
On your last stop, get out and inspect the brake system. Make sure you see that the rotors have some color to them; you are looking for a slight blue/purple hue to the face of the rotor. Put your hand up close to (do not touch) the wheel. Is it warm? Good! The brakes are doing their job. The last thing you will want to check is your mechanical expertise … how well did you perform all of the functions? Look inside the barrel of the wheel, checking for any possible brake fluid droplets or debris that shouldn’t be there. Take one last hot lap around your car inspecting your aluminum wheels and make sure there isn’t any brake fluid on them.
After a visual check is made, jump in and take the car for a drive, allowing the natural flow of air to pass over the brake system cooling it as much as possible, and remember to use as little brake as possible. Once this is complete, a 10-15-minute drive, go home and park your car, letting the brakes cool down to the ambient air temperature. The next time you go for a drive you should experience the ideal braking and there should be minimal brake pad noise (squeak).
In our example we are using the Wilwood ProSpindle 2-inch drop spindle. With the spindle prepped and ready to go you will begin by positioning the steering arm to the spindle. Here you will want to use Loctite 271 on the threaded surfaces of the hardware. Next you will want to make sure that the bolt pattern of your hubs match that of your wheels. Once bolt pattern is verified make sure the wheel studs are in position and begin to assemble the brake bearing using the recommended grease and adjusting nut. Following the proper adjusting nut specifications then you will install the O-ring and press fit dust cap.
The rotor is then attached to the hat using the 12 bolts and washers provided in the kit. Keep in mind this hardware will also need the use of Loctite 271 and this hardware needs to be torqued in an alternating sequence to 155 in-lb. (Careful, that’s “inch” pounds!) Although not shown in this installation, many hot rodders go the extra step and use standard 0.032-inch-diameter stainless steel safety wire. Once the hat/rotor assembly is slid onto the hub, make sure to align the small countersunk holes in the hat with the small threaded holes in the hub.
Next take the three (provided) flathead screws and torque to 85 in-lb. Once you are ready to install the calipers remember there is a right- and a lefthand caliper; make sure to install the correct caliper per side. Use the provided hardware and also make sure to use a lightweight oil to lubricate the caliper mounting studs. There is a procedure to make sure the calipers are aligned properly and there are also shims provided so that you can get the alignment correct.
You will want to start by attaching the caliper mounting bracket, orienting it so that the caliper will be mounted on the backside of the axle pointing to the rear of the car. Next up comes the rotor and hat and it goes together similar to the front with the hat attaching to the rotor using washers (0.265 id x 0.500 od x 0.063-inch thick) and bolts (1/4-28 x 0.750-inch long 12 point) using Loctite 271 on the threads and torque the bolts to 140 in-lb. (Again, safety wire can be used for an additional margin of safety.) You can now insert the pads into the calipers. This is a straightforward procedure, not unlike changing disc brake pads you have undoubtedly done many times before.
Next up are the brake lines will need to be installed and this will be best accomplished by good professional judgment. If you are unsure, check with an expert who understands what it is you are doing. Lastly, you will want to check wheel fitment as well as bleed the brakes. With the wheels make sure that they spin freely and there’s no interference/rub with any of the brake components.
Brakes have become both a performance as well as an aesthetic enhancement. Knowing this hot rodders have also gone to large window wheels to show off their latest brake kits. A lot of time and money is invested in high-performance brake kits, making sure they are installed properly will make all of the effort worthwhile.
Wilwood Engineering
(805) 388-1188
www.wilwood.com
Hot Rods & Hobbies
(562) 424-9425
www.hotrodsandhobbies.com