Metso HP300/400/500 Cone Crusher Lock & Release Cylinders: Seal Failure Causes & Spare Parts Guide
For Metso HP‑series cone crusher users, lock & release cylinders are critical hydraulic parts that keep your machine stable and safe.
When their seals fail, you face unplanned downtime, uneven product size and extra liner wear.
Hireate supplies OEM‑quality lock/release cylinders, seal kits and repair kits for HP300, HP400 and HP500.
This guide shows you: seal failure causes, early warning signs, and our spare parts solutions.
What Are Lock & Release Cylinders?
Lock Cylinders: 8 cylinders holding 185–190 bar pressure to fix the adjustment ring during crushing.
Release Cylinders: Retract the ring for liner change and maintenance.
Seals keep hydraulic pressure inside. Once damaged, locking force drops quickly.
Top 4 Causes of Seal Failure (Field‑Proven)
1.Overload & Tramp Iron Impact
Sudden pressure spikes from overload or tramp iron damage seal kits by extrusion and tearing.
2.Excessive Adjustment Ring Clearance
Worn threads create vertical play, causing side‑loading on cylinder rods and damaging wiper/piston seals.
3.Abnormal Locking Pressure
Pressure outside 185–190 bar speeds up seal aging. Faulty PS1‑A/PS2‑A switches or RLV5/RLV6 valves are usual causes.
4.Oil Contamination & Natural Wear
Dirty hydraulic oil, heat and cyclic pressure make seals harden, crack and leak over time.
Early Warning Signs of Seal Problems
Gradual locking pressure drop on G1 gauge
Oil leaks around cylinder rods or adjustment ring
Faster liner wear & unstable product gradation
Hard to release adjustment ring during liner replacement
Check cylinders immediately once you see these signs. Early seal replacement saves big downtime losses.
Hireate OEM‑Quality Spare Parts
We produce parts matching Metso original standards:
Complete lock/release cylinder assemblies
High‑pressure seal kits (NBR + polyurethane)
Rod seals, piston seals, wiper seals with OEM part numbers
All parts pass pressure and dimension tests for long service life.
Simple Maintenance Tips to Extend Seal Life
Keep locking pressure at 185–190 bar
Replace old seals on every liner change
Use clean, filtered hydraulic oil
Check adjustment ring clearance regularly
Final Note
Seal failure in lock/release cylinders is avoidable with proper maintenance and quality replacement parts.
Hireate provides reliable, cost‑effective spare parts for your Metso HP300/400/500 crushers.
Contact us for your customized quote today.