Stryker 721, Maintenance Manual

Page: 19 / 196

Service Information
15
HYDRAULIC CHECK VALVE REPLACEMENT (CONT’D)
Replacement of Valve #2
WARNING
To avoid personal injury or damage to the stretcher, remove the litter and the base hood before beginning
service on the jacks. Lower the jack rod completely to relieve the pressure on the pump piston side of the
jack. This will prevent large hydraulic fluid loss and possible damage when the base plugs are removed.
1. Remove the base plug (8) and discard the seal (9).
2. Remove the valve plug (10).
3. Using a stiff wire with a bent, pointed end, remove the valve (2) and the seal (11) and discard the seal.
4. Install the new seal (11) flat to the bottom of its hole with a 1/2” diameter rod.
5. Install the new valve (2) with the beveled end out (as shown in the illustration).
6. Install the valve plug (10) and tighten to 10 foot–pounds torque.
7. Install the new seal (9) with the base plug (8) and tighten to 10 foot–pounds torque.
8. Pump up the jack to the maximum height.
9. Be sure there are no hydraulic leaks before replacing the base hood and the litter.
Replacement of Valve (Poppet) #3
WARNING
To avoid personal injury or damage to the stretcher, remove the litter and the base hood before beginning
service on the jacks. Lower the jack rod completely to relieve the pressure on the pump piston side of the
jack. This will prevent large hydraulic fluid loss and possible damage when the base plugs are removed.
1. Remove the base plug (12) and discard the seal (13).
2. Remove the compression spring (14).
3. Using a small needle nose pliers, remove the poppet (3).
4. Install the new poppet (3).
5. Install the compression spring (14).
6. Install the new seal (13) and the base plug (12) and tighten to 10 foot–pounds torque.
7. Pump up the jack to the maximum height to check its operation.
8. Check for hydraulic leaks before replacing the base hood and the litter.