[{"data":1,"prerenderedAt":466},["ShallowReactive",2],{"\u002Fblog\u002Ftroubleshooting-hydraulic-pressure-loss":3,"related-\u002Fblog\u002Ftroubleshooting-hydraulic-pressure-loss":456},{"id":4,"title":5,"articleType":6,"author":7,"body":8,"category":438,"date":439,"description":440,"extension":441,"image":442,"lastModified":439,"meta":443,"navigation":444,"path":445,"seo":446,"stem":447,"tags":448,"__hash__":455},"blog\u002Fblog\u002Ftroubleshooting-hydraulic-pressure-loss.md","Troubleshooting Hydraulic Pressure Loss in Injection Molding Machines","howto","IMSPARES Technical Team",{"type":9,"value":10,"toc":421},"minimark",[11,15,19,24,46,50,55,58,90,94,107,112,126,131,145,149,156,182,186,206,210,221,225,245,249,356,360,381,385,388,414],[12,13,5],"h1",{"id":14},"troubleshooting-hydraulic-pressure-loss-in-injection-molding-machines",[16,17,18],"p",{},"Hydraulic pressure loss is one of the most common — and most disruptive — problems in injection molding. It can cause slow clamping, weak injection, incomplete filling, and inconsistent cycle times. This guide walks you through systematic diagnosis and repair.",[20,21,23],"h2",{"id":22},"symptoms-of-hydraulic-pressure-loss","Symptoms of Hydraulic Pressure Loss",[25,26,27,31,34,37,40,43],"ul",{},[28,29,30],"li",{},"Clamping force is lower than setpoint",[28,32,33],{},"Injection speed or pressure is below target",[28,35,36],{},"Cycle time has increased",[28,38,39],{},"Machine movements are slow or sluggish",[28,41,42],{},"Hydraulic pump is louder than normal",[28,44,45],{},"Oil temperature is higher than usual",[20,47,49],{"id":48},"step-by-step-troubleshooting","Step-by-Step Troubleshooting",[51,52,54],"h3",{"id":53},"step-1-check-the-basics","Step 1: Check the Basics",[16,56,57],{},"Before diving into complex diagnostics:",[59,60,61,68,74,80],"ol",{},[28,62,63,67],{},[64,65,66],"strong",{},"Oil level"," — Low oil starves the pump. Top up if below minimum",[28,69,70,73],{},[64,71,72],{},"Oil condition"," — Dark, milky, or smelly oil is degraded. Check for water contamination",[28,75,76,79],{},[64,77,78],{},"Oil temperature"," — Above 65°C reduces viscosity and pump efficiency. Check cooler function",[28,81,82,89],{},[64,83,84],{},[85,86,88],"a",{"href":87},"\u002Fparts\u002FO-TC-02","Oil filter"," — Clogged filters restrict flow. Check filter indicator or replace",[51,91,93],{"id":92},"step-2-inspect-the-hydraulic-pump","Step 2: Inspect the Hydraulic Pump",[16,95,96,97,101,102,106],{},"The pump is the primary pressure source. ",[85,98,100],{"href":99},"\u002Fparts\u002FHY-PW-06","Vane pumps"," and ",[85,103,105],{"href":104},"\u002Fparts\u002FHY-PW-07","piston pumps"," have different failure modes:",[16,108,109],{},[64,110,111],{},"Vane Pump Issues:",[25,113,114,117,120,123],{},[28,115,116],{},"Worn vanes — Low pressure at low speed, normal at high speed",[28,118,119],{},"Worn cam ring — Gradual pressure loss over time",[28,121,122],{},"Internal leakage — Oil temperature rises faster than normal",[28,124,125],{},"Shaft seal leak — Visible oil at the pump shaft",[16,127,128],{},[64,129,130],{},"Piston Pump Issues:",[25,132,133,136,139,142],{},[28,134,135],{},"Worn pistons\u002Fbarrel — Reduced volumetric efficiency",[28,137,138],{},"Swashplate wear — Erratic pressure control",[28,140,141],{},"Valve plate damage — Noisy pump, pulsating pressure",[28,143,144],{},"Control system failure — Pump doesn't respond to demand signal",[51,146,148],{"id":147},"step-3-test-the-control-valves","Step 3: Test the Control Valves",[16,150,151,155],{},[85,152,154],{"href":153},"\u002Fparts\u002FHY-CV-02","Directional control valves"," can cause pressure loss through internal leakage:",[59,157,158,164,170,176],{},[28,159,160,163],{},[64,161,162],{},"Solenoid check"," — Verify solenoids are energizing (listen for click, check LED indicators)",[28,165,166,169],{},[64,167,168],{},"Spool movement"," — A stuck spool prevents full flow. Check for contamination",[28,171,172,175],{},[64,173,174],{},"Internal leakage"," — Worn spool-to-bore clearance allows bypass flow. Measure case drain flow",[28,177,178,181],{},[64,179,180],{},"Proportional valve"," — Check amplifier card output and valve response curve",[51,183,185],{"id":184},"step-4-check-the-hydraulic-cylinders","Step 4: Check the Hydraulic Cylinders",[25,187,188,194,200],{},[28,189,190,193],{},[64,191,192],{},"Piston seal wear"," — Oil bypasses the piston internally",[28,195,196,199],{},[64,197,198],{},"Rod seal leak"," — Visible oil on cylinder rod",[28,201,202,205],{},[64,203,204],{},"Cushion valve"," — Stuck cushion valve restricts cylinder speed",[51,207,209],{"id":208},"step-5-inspect-hoses-and-fittings","Step 5: Inspect Hoses and Fittings",[25,211,212,215,218],{},[28,213,214],{},"Look for external leaks at hose connections",[28,216,217],{},"Check hose condition — Cracked, swollen, or hardened hoses should be replaced",[28,219,220],{},"Verify fitting tightness (but don't over-tighten)",[20,222,224],{"id":223},"pressure-test-procedure","Pressure Test Procedure",[59,226,227,230,233,236,239,242],{},[28,228,229],{},"Install a calibrated pressure gauge at the pump outlet",[28,231,232],{},"Set the machine to manual mode",[28,234,235],{},"Activate clamping at full pressure",[28,237,238],{},"Compare gauge reading to the controller setpoint",[28,240,241],{},"If gauge reads low, the problem is upstream (pump or relief valve)",[28,243,244],{},"If gauge reads correct but machine is weak, the problem is downstream (valves, cylinders, or leaks)",[20,246,248],{"id":247},"common-causes-and-solutions","Common Causes and Solutions",[250,251,252,268],"table",{},[253,254,255],"thead",{},[256,257,258,262,265],"tr",{},[259,260,261],"th",{},"Cause",[259,263,264],{},"Solution",[259,266,267],{},"Parts Needed",[269,270,271,285,298,310,323,334,345],"tbody",{},[256,272,273,277,280],{},[274,275,276],"td",{},"Clogged oil filter",[274,278,279],{},"Replace filter element",[274,281,282],{},[85,283,284],{"href":87},"O-TC-02",[256,286,287,290,293],{},[274,288,289],{},"Worn vane pump",[274,291,292],{},"Replace or rebuild pump",[274,294,295],{},[85,296,297],{"href":99},"HY-PW-06",[256,299,300,303,305],{},[274,301,302],{},"Worn piston pump",[274,304,292],{},[274,306,307],{},[85,308,309],{"href":104},"HY-PW-07",[256,311,312,315,318],{},[274,313,314],{},"Leaking directional valve",[274,316,317],{},"Replace valve spool or complete valve",[274,319,320],{},[85,321,322],{"href":153},"HY-CV-02",[256,324,325,328,331],{},[274,326,327],{},"Cylinder seal failure",[274,329,330],{},"Replace piston and rod seals",[274,332,333],{},"Seal kit",[256,335,336,339,342],{},[274,337,338],{},"Degraded hydraulic oil",[274,340,341],{},"Complete oil change with fresh ISO VG 46\u002F68",[274,343,344],{},"—",[256,346,347,350,353],{},[274,348,349],{},"Relief valve out of adjustment",[274,351,352],{},"Reset pressure, replace if worn",[274,354,355],{},"Relief valve",[20,357,359],{"id":358},"prevention","Prevention",[25,361,362,365,372,375,378],{},[28,363,364],{},"Change hydraulic oil every 4,000-6,000 operating hours",[28,366,367,368,371],{},"Replace ",[85,369,370],{"href":87},"oil filters"," every 3-6 months",[28,373,374],{},"Monitor oil temperature — install alarms for high temperature",[28,376,377],{},"Keep the reservoir clean — prevent contamination during oil changes",[28,379,380],{},"Schedule annual pump efficiency tests",[20,382,384],{"id":383},"need-replacement-parts","Need Replacement Parts?",[16,386,387],{},"We stock all major hydraulic components for injection molding machines:",[25,389,390,396,402,408],{},[28,391,392,395],{},[85,393,394],{"href":99},"Hydraulic Vane Pumps"," — Taixin, Vickers, YUKEN",[28,397,398,401],{},[85,399,400],{"href":104},"Hydraulic Piston Pumps"," — YUKEN, Rexroth compatible",[28,403,404,407],{},[85,405,406],{"href":153},"Directional Control Valves"," — Cetop 3\u002F5\u002F7",[28,409,410,413],{},[85,411,412],{"href":87},"Hydraulic Oil Filters"," — Suction and return line",[16,415,416,420],{},[85,417,419],{"href":418},"\u002Frequest-quote","Request a quote"," with your machine model and symptoms, and we'll recommend the right parts.",{"title":422,"searchDepth":423,"depth":423,"links":424},"",2,[425,426,434,435,436,437],{"id":22,"depth":423,"text":23},{"id":48,"depth":423,"text":49,"children":427},[428,430,431,432,433],{"id":53,"depth":429,"text":54},3,{"id":92,"depth":429,"text":93},{"id":147,"depth":429,"text":148},{"id":184,"depth":429,"text":185},{"id":208,"depth":429,"text":209},{"id":223,"depth":423,"text":224},{"id":247,"depth":423,"text":248},{"id":358,"depth":423,"text":359},{"id":383,"depth":423,"text":384},"Troubleshooting","2026-09-30","Diagnose and fix hydraulic pressure loss problems in injection molding machines. Common causes, step-by-step troubleshooting, and replacement parts guide.","md",null,{},true,"\u002Fblog\u002Ftroubleshooting-hydraulic-pressure-loss",{"title":5,"description":440},"blog\u002Ftroubleshooting-hydraulic-pressure-loss",[449,450,451,452,453,454],"hydraulic","pressure loss","troubleshooting","vane pump","piston pump","control valve","1aJbM-73MLxZOCSQcT3fjpGr1jCzSAsVFTq9YH2jAVM",[457,461],{"title":458,"path":459,"description":460,"date":439,"category":438},"Short Shots in Injection Molding: Causes and Fixes","\u002Fblog\u002Fshort-shots-injection-molding-causes-fixes","Short shots mean incomplete parts. Here are the real causes — not just the textbook answers — and what actually fixes them on the shop floor.",{"title":462,"path":463,"description":464,"date":465,"category":438},"5 Hydraulic Oil Problems That Kill Your Injection Molding Machine","\u002Fblog\u002Fhydraulic-oil-problems-injection-molding","Dirty oil, wrong viscosity, overheating, aeration, and water contamination — these five hydraulic oil issues cause most machine breakdowns. How to spot them before they cause real damage.","2026-03-22",1790784693020]