Troubleshooting

If symptoms of poor performance develop, the following chart can be used as a guide to correct the problem. When diagnosing faults in operation of the grinder, always make sure the hydraulic power source is supplying the correct hydraulic flow and pressure to the tool as listed in the table. Use a flowmeter known to be accurate. Check the flow with the hydraulic fluid temperature at least 80 °F/27 °C.

	PROBLEM	CAUSE	SOLUTION
	Low performance.	Incorrect hydraulic flow.	Check that the power source is pro-
			ducing 4–12 gpm/15–45 lpm at
			1000–2000 psi/70–140 bar.
		Defective quick disconnects.	Check quick disconnects.
	Fluid leaks at motor cap assem-	Fasteners loose.	Tighten	to recommended torque
	bly face.		value.
		Face O-ring worn or missing.	Replace as required.
		Motor cap assembly/main housing	Replace as required.
		damaged.
	Fluid leaks at reversing spool.	Damaged O-rings.	Replace as required. Refer to assem-
			bly instructions to prevent cutting the
			O-rings.
		Wrong hydraulic fluid. Circuit too hot.	See Hydraulic System Requirements
			for correct fluid/circuit specifications.
		Hydraulic pressure and return re-	Correct hose connections.
		versed.
	Fluid gets hot, power unit work-	Open-center tool on a closed-center	Use tool to match circuit.
	ing hard.	circuit and vice versa.
		Too much fluid going through tool.	Adjust flow for 12 gpm/34 lpm maxi-
			mum.
		Circuit is generating high heat with flow	Use pump size and rpm for produc-
		controls, open relief valve, etc.	ing needed flow only. Eliminate circuit
			heating cause.
		Circuit has contaminants that have	Replace worn pump and valves. In-
		caused pump and valve wear and high	stall a large clean filter and keep cir-
		heat generation.	cuit fluid clean.
	Tool doesn’t run.	Power unit not functioning.	Check that the power source is pro-
			ducing 4–12 gpm/15–45 lpm at
			1000–2000 psi/70–140 bar.
		Coupler or hoses blocked.	Remove obstruction.
		Mechanical failure.	Disassemble tool and inspect for
			damage.
	Tool runs backwards.	Pressure and return hoses reversed.	Correct for proper flow direction.
			Grinding wheel should rotate counter-
			clockwise when viewed from the shaft
			end.
	Grinding wheel comes to abrupt	Porting spool incorrectly assembled.	Refer to Service Manual.
	stop after trigger is released.	Check valve in trigger spool not func-	Replace	trigger spool assembly.
		tioning correctly.	Check valve not serviceable.
		Mechanical failure.	Disassemble tool and inspect for
			damage.
14 ► GR29 User Manual

TROUBLESHOOTING

PROBLEM

CAUSE

SOLUTION