Leak-Down Testing

Lifter must be assembled while submerged in test fluid. Proceed as follows:

1. Install suitable adapter tool (BT-105-2) in reservoir of suitable leak-down tester (BT-60) and fill reservoir with test fluid to 1/2" below top of reservoir. Assemble ball check, spring and retainer into plunger with flange pressed tight against bottom of recess in plunger.
2. Install spring over ball check retainer. Hold plunger with spring up and insert into lifter body (to prevent cocking spring). Place assembly in tester cup and position push rod seat into plunger. Position 1/4" steel test ball on push rod seat and lower tester ram until it contacts steel ball. Allow ram to move downward by its own weight until air bubbles disappear. Repeat several times until all air is expelled from lifter.
   CAUTION: Do not attempt to expel air from lifter by pumping ram.
   Fig 1: ROCKER ARM & VALVE ASSEMBLIES

   Courtesy of GENERAL MOTORS COMPANY
3. After air removed, allow ram to bleed down lifter to expose ring groove and install retaining ring. Adjust ram screw so it contacts steel ball in push rod seat when pointer is at start line. Raise arm and start test by resting ram on steel ball.
4. Rotate reservoir one revolution every two seconds, and time indicator from start line to stop line. Allowable leak-down time is six seconds for used lifters, and 9-60 seconds for new lifters.
   NOTE: If lifter within specifications, place in service without removing test fluid.
   Fig 2: HYDRAULIC VALVE LIFTER ASSEMBLY

   Courtesy of GENERAL MOTORS COMPANY