Relief Valve - jcb JS300 Service Manual

Symptoms
Pressure does not rise at all
Relief pressure is unstable
Relief pressure is out of control 1. Wear due to foreign matter.
Oil leakage
E-238

Relief Valve

Table 3.
Possible Causes
1. The main poppet, sleeve or pilot poppets
are sticking open or foreign matter is in the
valve seat.
1. The pilot poppet seat is damaged.
2. The piston is sticking to the main poppet. Remove the surface scratches. Clean all
2. Lock nut and adjuster are loose.
1. Damaged seat or worn O-ring.
2. Parts are sticking due to foreign matter. Check for scratches, cuts or foreign matter.
9813/5100-1
Section E - Hydraulics
Hydraulic System Fault Finding
Countermeasures
1 Check whether foreign matter is in
each poppet.
2 Check whether each part is sliding
smoothly.
3 Clean all the parts.
Replace the damaged parts.
the parts.
Replace the worn parts
Reset the pressure and tighten the lock nut
to the rated torque.
Replace damaged or worn parts. Check
whether each part is sliding smoothly.
Clean all the parts.
Relief Valve
E-238