A few issues back, we upgraded a Tri-Five Chevy to a complete coilover suspension from Heidts, with big Wilwood brakes. Everything went on without a hitch, but when we were all done the brake pedal feel was too twitchy. The brakes worked fantastic, stopping the car with no problem, but the pedal had no feel, as if just the weight of your foot was enough. We wanted some feel to the brakes since the car will be seeing some autocross duties.
After speaking with the tech line at Wilwood and confirming we had the proper brake lines and the system was free from air, we figure there could only be one parameter causing our too-easy-to-push brake pedal, and that is the brake pedal arm. The brake pedal arm is not just a hunk of metal with a pad at the bottom; there is some engineering built into it. Manual and power-equipped vehicles would have a different point at which the master cylinder rod would hook up, changing what they call the pedal ratio. Manual systems like a ratio of 6:1, while power systems like a 4:1 ratio.
Once we found we had a manual drum ratio pedal hooked to a power system, the reason for the too-soft pedal became apparent. Basically, the pedal was overly sensitive due to too much pressure being applied too quickly. To cure the issue, we had two options: move the master cylinder hole to change the ratio to support a power system, or take the booster out of the equation. Since our car has a 502 big-block, clearance and vacuum are minimal, so we decided to just remove the booster altogether and run manual brakes. As soon as we did this, all was right with our pedal feel.
Even though we have good feel in our system, now the brake pedal itself was plain. With the current upgrades going on with this car, a plain old brake pedal just wouldn’t do. We used a Lokar Eliminator gas pedal in the car when it was first built, and it has served us well, so we looked to Lokar again for a brake pedal upgrade. Our first thought was to get a pedal pad and attach it to our stock arm. Well, that thought went out the door when we saw the company’s complete billet aluminum arm. It’s big and beefy, and is a bolt-in installation. We will get all the looks of a custom-made piece, with the simple installation of a factory arm. We decided a black arm with a large pad was just what we needed. We also picked up a new Eliminator gas pedal assembly in black so all components will match. The following photos will show what it takes to swap out the brake arms, and at the end we will even give you a nice diagram that maps out how to figure out your own pedal ratio.
1. Here is what we are going to upgrade, the stock brake arm. We are changing the gas pedal so all the components will match. We could have gone with a brushed brake arm and not changed the gas pedal, but we think the black coating looks better under the dash and will be a lot easier to care for.
2. Step one in removing the stock brake arm is to remove the lock pin from the master cylinder clevis.
3. The brake arm axle is held in place with a small nut and bolt.
4. Once the bolt is removed, the axle will slip right out. The arm will almost fall out, and a large return spring will come with it. Make sure to retain the spring, as it will be reused. Unless you are going to quickly install the new brake arm, we would recommend unplugging the brake light switch, as the brake lights will remain on until a new arm is in place.
5. Here is a side by side to give you a good idea of how the Lokar arm compares to the stock unit. As you can tell, the new piece is big and beefy, but still weighs less.
6. Since the Lokar arm is much thicker, a new clevis is provided. We threaded the new clevis as far down as it would go to give us the most room to install the arm. We temporarily installed the new brake arm without the spring and spacer, just to set the clevis. It will need to be adjusted so the pin will slip in and hook to the brake arm without putting any pressure or preload on the master. Now we removed the brake arm so we could put it back in properly with all the supporting items.
7. Here is how all the little items will go together under the dash. Lokar provides two Delrin spacers; the thick one will slip inside the return spring.
8. We got this picture from Lokar; it clearly shows how the return spring is positioned.
9. When you are under the dash doing this job, it’s going to be a bit of a pain since you need to align the spring, spacers, and pedal arm all at once while you slip in the axle. We found a drift or punch installed first from the opposite side allowed us to put the items in a bit easier. Because the axle is hollow, we could push it in while using the punch to align each item as the axle slipped in. Once everything was in, we readjusted our brake light switch, and then stepped out to admire the new goods.
10. Here is the complete package with the new gas pedal in place. Now both items not only match, they look a lot better than the original stuff.