Finding the Proper Free Play in Clutch and Pedal Height
In order to drive safely, it’s imperative that your brake and clutch pedals are sitting at their proper height. You can test this by measuring something called free play, which is the distance between the pedals when not depressed and the point at which they begin to engage when you press them with your foot. Too much free play and the pedals feel loose or spongy. Too little, and it’s difficult to press them and get the brake and clutch systems to engage.
Most brake and clutch pedals should have just a little bit of free play, usually about a centimeter, which is less than half an inch. If you feel that your free play is more generous than this, or that you don’t have any at all, you’ll need to adjust your pedals.
Testing Free Play
It’s not that difficult to test the free play on your car’s pedals. Here’s what you’ll need to start:
- Open-end wrenches
- Line wrenches
- Wite-Out, colored nail polish, or another way to make a clear mark on a metal surface
There are two ways to test free play. With the car turned off, use one hand to move the pedal up and down. You should be able to gauge if your play is too generous or too short. If not, take a ruler and place one end against the floor and the other alongside the pedal. Lift the pedal to the top of its range and note the measurement. Now, push the pedal just far enough for it to make contact on the other side. This contact point is the point at which the pedal actually starts to activate the braking system or the clutch, compared to the floppy up and down movement you’ll get in the area of the pedal—in other words, the free play. Subtract measurement two from measurement one, and this is the amount of your free pushrod.
Adjust Pedal Height
Now you’re ready to fine-tune the pedal height. Follow the pedal upward to the point at which it attaches to a rod, called the push rod. Before you touch anything with your tools, it’s a good idea to mark the pushrod with your Wite-Out or nail polish. You just need a dot on the part that’s facing down toward you. This dot will let you be sure you don’t rotate the pushrod until you want to. Any rotation ahead of time will throw off your measurements.
Next, locate the locking nuts for the push rod. In the photo shown here, a 12-point star nut and a hex nut keep the rod from drifting out of adjustment on its own. Here’s where your line wrenches come into play. Slip a line wrench over each of the lock nuts and loosen by turning them in opposite directions. Don’t let the pushrod rotate yet (if it does rotate a little, use your mark to bring it back). Any rotation will cause the free play to change, and you’re not ready for that to happen yet.
With the lock nuts loosened, rotate the push rod—you may need to use pliers to grip the rod and make it more easy to rotate. As it rotates, test the pedal’s free play by pushing it with your hand. It will slowly increase or decrease.
Once you have the free play adjusted properly, tighten the lock nuts and drive around the block, testing the pedal heights to make sure they don’t feel spongy.