JLG 340AJ Service Manual - Manual (Page 204)

SECTION 5 - HYDRAULICS
5-46 – JLG Lift – 3121259
Run a fingernail or pencil tip across the diameter of the sealing
land surface (see illustration).You should feel no deep or out-
standing grooves.These may decrease pump flow. Lap or
replace if grooves or nicks are present. Inspect the mating sur-
faces of the endcap and valve plate for any possible contami-
nation; even a few thousandths of an inch may affect pump
operation.
Ensure plate appears flat and smooth on both the running
face and the bottom surface. Perform a magnetic particle
inspection to detect cracks. Replace if any cracks exist.
ENDCAP
Inspect the endcap. Inspect all machined sur faces for
scratches or pits. Carefully check the bearing surface for wear.
Inspect valve seats carefully for wear or cracks. Replace if dam-
aged.
HOUSING
Inspect the housing to ensure that it is clean and free of for-
eign material. Inspect the swashplate bearing surfaces, and
endcap and control mating surfaces.
PRESSURE LIMITER
Pressure limiter valves are available as complete units only. If
you suspect valve malfunction, replace the valve(s) and test
pump operation. Replace O-rings before reassembly.