Valve Flaw Leads to Faulty Pressures

The circuit below was working for several years when the pressure-reducing valve on the clamp cylinder started leaking oil into an assembly bolt cavity. It appeared that a casting flaw finally failed after thousands of pressure cycles. The company purchased and installed a new module. However, the cap end would see full system pressure crushing the product while the rod side pressure would see reduced pressure as designed.

Maintenance returned the valve and replaced it with a new one, but it had the same problem. They examined the old valve and confirmed the new ones had the same model number as the failed one.

What was the problem?

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