Maximum Motorsports Manual Brake Conversion 101
Our Project 666 car, a 1986 5.0 Fox-body Mustang, has recently undergone an upgrade to a Wilwood brake kit. The new brakes, rotors and calipers made a huge difference in stopping power but still lacked that little something for outrageously quick, stop-on-a-dime performance. Looking for that extra edge, we went to the Mustang specialists at Maximum Motorsports for help. Since we plan on putting Mickey Thompson Drag Tires on the back wheels, updating our braking system to include a TCI Roll Stop at the same time would prove to be a time-saver.
Since 1992 when the company was founded, Maximum Motorsports has established itself as a leader in Mustang performance parts. Because we are looking at adding some horsepower (a lot of horsepower, to be honest), we needed to start thinking about stopping our ‘Stang before the track runs out. The adrenaline rush of getting to the end of the strip and finding out your brakes are weaker than you would like is a bit too much for the faint of heart. We called Chuck Schwynoch, CEO of Maximum Motorsports, to get the lowdown on manual brake conversions for Mustangs. Chuck assured us that switching to manual brakes would only moderately increase the effort required for braking, especially using his company’s manual brake conversion system, due to the advanced pedal arm geometry designed in the kit.
Chuck went on to explain why we would benefit in using manual brakes in our project car. Two of the most popular selling points were less weight and more space. Because manual brakes do not require a power booster, that entire assembly is removed. The removal of the power assist booster saves a lot of space under the hood and eliminates the need for the engine to supply vacuum to the booster, which is nice when you’ve got a lumpy cam installed.
The bulky, heavy old power assist unit will be taking up space in the recycling bin instead of under the hood from now on.
The Roll Stop
Not wanting to overlook any technical advantage we could get, we made a call to TCI Automotive for the scoop on their Roll Stop kit. We talked with Scott Miller at TCI and he enlightened us on the unique nature of their roll stop.
It’s pretty much a given that if you want to do super-human burnouts and heat the meats on the rear, you need a roll stop to lock the front brakes. According to Scott, on most roll stops you pump up the brakes and press the switch to lock the fronts, then take your foot off the brake pedal. At that point, the pressure you have on the front brakes is what it is. With the TCI Roll Stop, if you don’t have enough pressure you can step on the brake pedal and add more pressure to the front brakes due to the one-way valve design in the solenoid.
Making the decision
So, let me see if we get this correct; in switching to a manual brake system, we can save a little on weight, provide a little extra room in a crowded engine bay and save some power because the engine doesn’t have a parasitic vacuum draw from the power assist booster, and all we have to do is step on the brake pedal slightly harder. That seemed like a real “no brainer” to us, so we decided to convert. As for the Roll Stop, we were going to be moving the brake lines anyway, so it was just too cool to pass up and we put one on order. How much space would we be saving? In removing the vacuum assist, the master cylinder would move six and a half inches closer to the firewall. We knew to be prepared to move the existing brake lines for the change. Maximum Motorsports also sells brake line adapter kits to assist with the installation.
Our project Mustang awaits the Maximum Motorsports Manual Brake Conversion Kit.
When the Maximum Motorsports manual brake conversion kit came in, we were delighted and surprised to find a new brake pedal is included in the kit. The brake pedal not only corrects the pedal geometry, but as an added bonus, the pedal pad can be mounted in one of six different positions on the pedal arm. This makes it possible to “fine tune” the mechanical leverage ratio and even change the position in relationship to the accelerator pedal to aid in the “heel and toe” downshifting technique, for those using it in a street or roadrace application.
An adjustable length pushrod attaches to the pedal arm with a spherical rod-end, eliminating the sloppy fit of the stock pushrod to further improve pedal feel. A CNC-machined aluminum adapter block bolts to the firewall in place of the vacuum booster, and mounts any 1979-1995 Mustang master cylinder. By using readily-available aftermarket master cylinders, you are assured of always being able to find a replacement one easily, whether at home or at the track.
The adjustable length pushrod with spherical rod end provides a better fit than the stock pushrod.
Chuck explained that for a stock 1979-93 Mustang brake system with the original calipers, rotors, and rear drums, you must use the stock master cylinder size that was originally fitted on 1987-93 power brake-equipped 5.0L Mustangs. The 20.6mm bore of that master cylinder is the best choice to provide decent braking ability with reasonable pedal effort.
For Mustangs equipped with rear disc brakes, the master cylinder recommendation depends upon the situation. For a 1979-93 Mustang equipped with rear disc brakes, Maximum Motorsports recommends a 1” bore master cylinder (1993 Cobra). For 1994-95 Mustangs (both GT and Cobra) Maximum Motorsports recommends a 15/16” bore master cylinder (1994-95 Cobra).
Some drivers of road course-driven Mustangs prefer a master cylinder one size larger because it provides less pedal travel. Chuck suggests trying the recommended size first, and only switching to a larger master cylinder if track testing indicates a change is warranted.
Finally. A good set of instructions.
Another pleasant surprise was the fully illustrated and very complete instruction manual. Rarely do we encounter a step-by-step installation manual that is as thoroughly detailed. Compared to many aftermarket part instructions, these were great. It was very obvious that a great deal of research and development went into this kit, from the components included right down to the instructions. We were pleased with the kit even before the installation began.
The next day our TCI roll stop came in and we were ready to start the install. The kit came complete with a solenoid valve, a push button microswitch, a red powder-coated mounting bracket, an in-line fuse connector, and mounting hardware. And once again, easy instructions. A quick trip to the parts store for some brake fluid and we were set.
Bolting it up
Normally, we figure that real men don’t read instructions and we just start bolting stuff on, but seeing as we were dealing with brakes and the boss was going to do the test drive, we were following the instructions to the letter. There was no difficulty with the installation or understanding the directions. I did have a question for Maximum Motorsports’ tech department about using a Wilwood brake bias control and the TCI Roll Stop in the plumbing. The tech department was extremely helpful and even provided a copy of their brake bias control instructions. As for TCI’s Roll Stop, the installation couldn’t have been easier.
The schematics tell the tale for installing the Roll Stop in the brake system and hooking up the power.
We started the installation with our usual safety precaution of disconnecting the battery and making sure that we had plenty of shop rags and containers for drained brake fluid. Following the instructions, we measured the stock pedal height and pedal free play. The next task was to remove the pedal box from the vehicle so that the pedal and brake light switch could be replaced. In order to remove the pedal box, several panels and the steering column had to come out of the car. It’s a good idea to take lots of photos during the disassembly, in case there are any questions when it comes time to reassemble. We found it easiest to remove the driver’s seat to provide plenty of room to remove the four nuts that secure the pedal box to the firewall. Finally, we removed the power assist assembly and master cylinder from the engine firewall.
Removing the power assist assembly.
Bare firewall where the power assist and master cylinder used to be.
The stock pedal box and pedals.
Once the pedal box was removed, we installed the new brake pedal from the Maximum Motorsports kit. The instructions were very clear on which parts to discard and which ones would be reused.
A few pieces from the stock brake assembly are reused.
Pedal box with Maximum Motorsports brake pedal installed.
With the new brake pedal mounted in the pedal box, we then connected the adjustable pushrod to the pedal and reinstalled the pedal box, steering column and panels back into the car.
The pushrod connects to the new pedal via a rod end, which makes for a precise, solid connection with no slop.
The other side of the firewall
With the work done inside the car, it was time to get under the hood and reassemble the master cylinder and brake lines. We added the TCI Roll Stop to the front brake lines as part of the upgrade. Much to our amazement, our Wilwood Master cylinder used National Pipe Thread fittings and the TCI Roll Stop used AN fittings. We found some adapter fittings from Wilwood that adapted the stock brake lines to the master cylinder and the Roll Stop.
The master cylinder adapter block bolts directly to the firewall in place of the brake booster.
We ended up with a clean installation on our manual brake conversion, and a braking system that we can grow into. The test drive provided proof that a manual brake conversion was indeed a wise upgrade.
TCI Roll Stop solenoid valve mounted to the strut tower.
Points to ponder
Chuck Schwynoch reminded us that, “The Maximum Motorsports brake pedal is not intended to be used with stock, unmodified brake systems.” The pedal ratio is would be incorrect for a stock system and may cause an increase in stopping distance. The manual brake conversion kit mounts into the stock pedal box without drilling any new holes, and allows for use of the stock cruise control. If you have a real street/strip car and it is fitted with factory cruise control, you can change to manual brakes and still be able to use it on the highway when you’re heading to the track.
Maximum Motorsport’s engineers work with the car manufacturers and aftermarket brake manufacturers to ensure proper fit and safe application of the brake kits. In our case, we were using the MM brake conversion kit with a Wilwood master cylinder. Maximum Motorsports had already done the research with representatives from Wilwood to ensure that the kit would be compatible. Thanks to the research and development put in up front, the kit we installed went in smoothly. When we had a question about the pedal feel, Chuck answered it quickly and clearly. We give the MM Manual brake conversion kit two thumbs up.