Air Brake Leak Test. Is Initial PSI Loss Normal?

Is it normal for the pressure to initially drop when first pushing down the foot break? There is way more than a 3 PSI loss when I first press on the brake. Do you start the minute countdown after the initial loss in pressure?

System Leak Check: Shut off the engine, chock your wheels, (if necessary), release parking brake (push in), fully apply the foot brake and hold it for one minute. Check the air gauge to see if the air pres- sure drops more than 3 pounds in one minute (single vehicle).

Once you push the pedal, it does go down because you released air to activate the brakes. every time you press the pedal it will do this.

In MO, we needed to say "Im going to push on the pedal and wait for the needle to stabilize, then i will count for one minute with no more than 3 PSI...."

Once you push the pedal, it does go down because you released air to activate the brakes. every time you press the pedal it will do this.

In MO, we needed to say "Im going to push on the pedal and wait for the needle to stabilize, then i will count for one minute with no more than 3 PSI...."

Thanks. Appreciate it.