Troubleshooting Loss of Power in 2008 Caterpillar 305C-CR: Relief Valve Engagement Issue?

Question:

Hello, I am the owner of a 2008 Caterpillar 305C-CR with approximately 4200 hours of usage. I purchased this machine around 6 months ago and initially had no issues lifting large rocks during the spring season. However, during the summer, the boom cylinder underwent a rebuild at a reputable shop. Ever since the cylinder was replaced with new seals and a new rod, I have noticed a decrease in power. Previously easily lifting rocks weighing around 4,000 lbs now seems out of reach as it appears that the relief valve engages quickly. What could be causing this sudden loss in power? Any insights would be greatly appreciated. Thank you!

Top Replies

Whenever I've encountered this issue, it's usually the fuel filter that's to blame. If your equipment is struggling to lift or the engine sounds like it's under strain, there may be a problem with the fuel filtration system. If the RPMs remain consistent, the relief valve may have been tampered with. It's puzzling why someone would adjust it for such a simple repair. It could be worthwhile to begin by replacing the hydraulic filter if the engine is maintaining RPM. This may resolve the issue and improve performance.

Hello KSSS, thank you for your response. I realized I forgot to mention a few things. When the boom's cylinder was replaced, the mechanic also replaced the fuel and oil filters with non-genuine Cat parts labeled as "will fit". Despite this, the engine operates smoothly without any issues while lifting heavy rocks, and there are no blinking warning signs. Additionally, during troubleshooting the boom's cylinder issue, the mechanic temporarily swapped the boom relief valve with the undercarriage valve. However, upon checking this morning, everything seems to be in its proper place as numbered by the mechanic. It is possible that the issue lies with a dirty hydraulic filter. Thank you.

I am considering trying that. The next step would be to ensure all the reliefs are correctly positioned.

Hello KSSS, Thank you once again for your response. I plan to purchase a hydraulic oil filter from CAT this week and will seek guidance on how to replace it in my equipment. Is it possible for the relief valves' settings to be unintentionally adjusted during a swap test? I am not well-versed in their proper calibration, so I am curious if their settings could have been changed accidentally during the swap. Thank you.

It is important to note that certain functions require specific relief settings, such as the boom cylinder valve needing a different setting compared to the auxiliary circuit. While it may not be easy to accidentally change the settings, it is crucial to ensure the correct relief settings for optimal performance.

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Frequently Asked Questions (FAQ)

FAQ: 1. Why is my 2008 Caterpillar 305C-CR experiencing a sudden loss in power after a boom cylinder rebuild?

Answer: - The decrease in power could be due to the relief valve engaging quickly after the cylinder replacement. This may be impacting the machine's ability to lift heavy loads as before.

FAQ: 2. What could be causing the relief valve to engage quickly after the boom cylinder rebuild?

Answer: - The new seals and rod installed during the rebuild could potentially be affecting the hydraulic system, leading to the relief valve activating sooner than necessary.

FAQ: 3. How can I troubleshoot the issue of loss of power in my Caterpillar 305C-CR after the cylinder replacement?

Answer: - You may need to inspect the hydraulic system components, check for any leaks, ensure proper hydraulic fluid levels, and consider if the relief valve settings need adjustment.

FAQ: 4. Should I seek professional assistance to resolve the power loss issue in my Caterpillar 305C-CR?

Answer: - If you are unfamiliar with hydraulic systems or troubleshooting heavy machinery, it is advisable to consult with a certified technician or Caterpillar dealer to diagnose and address the issue effectively.

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