John Deere 318 - Manual (Page 364)

G
HYDRAULIC SYSTEM IS NOISY
• Check power steering valve, if equipped, or hydraulic control valve for overheating. If either valve is too
hot to touch after 1/2 hour of operation, disassemble valve and repair internal leak. See Section 60 or 70.
• Adjust hydrostatic transmission linkage for positive neutral position: GO TO 1Ô
• Check steel hydraulic lines for vibration. Especially the line that runs from the charge pump to the steering
valve on later 318 and 420 models, or the line that runs from the charge pump to the SCV on early 318
and 420 models. Secure with clamps or replace with a rubber pressure hose rated at 8274 kPa (1200 psi).
• Adjust charge relief valve so that charge pressure is above 1379 kPa (200 psi). The increased charge
pressure will not cause any problems and it may eliminate the noise, if it is caused by charge relief valve
chattering: GO TO
3c
• Increase implement relief pressure to upper limit of specification: GO TO 4b
H
NO HYDRAULICS AFTER BEING SERVICED
• Check for improper charge pump installation (180 degrees off). See Section 50.
• Check for proper installation of transmission output shaft bearing into aluminum case. If installed too
shallow, the motor rotating group will not contact the valve plate. See Section 50.
I
CHARGE PUMP SEAL REPEATEDLY FAILS
• Inspect the seal surface on the shaft.
• Inspect seal for cuts which may be caused by installing seal over shaft without covering sharp splines.
• Check for a loose or worn U-Joint on the drive shaft.
• Inspect charge pump for wear or damage. Charge pressure may be getting into the seal area because of
internal pump leakage. See Section 50.
MX,159025015,9 -19-20APR95
MX,159025015,10-19-20APR95
MX,159025015,11-19-20APR95
Diagnosis, Tests and Adjustments/Troubleshooting Guide
TM1590 (17MAY95)
250-15-4
316, 318 & 420 Lawn and Garden Tractors
020895
250
15
4