K - Excessive Brake Pedal Effort

K1- Check Brake Application
- With the engine "OFF" apply and release brake pedal five times to deplete all vacuum from the power brake booster.
- Apply the brake pedal and hold with light pressure then start the engine.
- With the same pressure applied, does the pedal remain at the same location without moving down when the engine starts ?
YES - Go to K2.
NO - Go to K4.

K2- Power Brake Booster Leak Test
- Run the engine at medium idle, release the accelerator pedal and turn the engine "OFF".
- Wait 90 seconds and apply brakes. Two or more applications should be power assisted.
- Does power brake booster work ?
YES - Go to K4.
NO - Go to K2.

K3- Power Section Check Valve Test
- Disconnect vacuum hose for power brake booster check valve at manifold and remove from booster.
- Blow air into valve.
- Does air pass through valve in only one direction ?
YES - Replace power brake booster and repeat step K1. Service and Repair
NO - Install new power brake booster check valve and repeat step K1. Service and Repair

K4- Power Section Test
- Disconnect vacuum hose from power brake booster check valve.
- Connect a vacuum gauge to hose and run engine at "IDLE".
- Is vacuum above 40.5 kPa (12 in-Hg) ?
YES - Replace power brake booster and repeat K1.
NO - Service or replace vacuum hoses and vacuum fittings. Diagnose and service engine for cause of low vacuum.