I am having an issue with my 05 Cat MTL 257B losing hydraulic pressure. I've replaced and resealed several parts of the machine, and it's a brand new Perkins engine. However, it's still losing pressure, especially when I want to turn left or right or lower the boom. Could this be a bypass valve issue or something else? Any thoughts?
Top Replies
It sounds like it could indeed be a bypass valve issue. I had a similar problem and replacing the valve solved it. Have you checked for any leaks in the hydraulic lines?
April 24, 2024
mechman1978
Check the hydraulic fluid level as well. If it's low, that could cause the pressure loss. Also, make sure the filters are not clogged.
April 28, 2024
hydrofixer
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I had a similar issue with my 257B, and it turned out to be a faulty pressure relief valve. Replacing it fixed the issue.
May 2, 2024
wrenchwizard
You might also want to check the hydraulic pump itself. If the pump is failing, it could cause loss of pressure. Look for any unusual noises or drops in servo performance.