An autocrane equipped with an LS hydraulic system and a multi-section Bosch Rexroth control valve has developed a fault in one section of the hydraulic distributor. The corresponding hydraulic cylinder operates very slowly, while all other sections and cylinders function normally. The problem appeared suddenly. The hydraulic pump appears to be working correctly, since all other crane functions operate at normal speed and power. Hydraulic hoses and lines were checked and swapped, but the problem remains on the same valve section. When the cylinder is connected to another section, it works normally. I also swapped the spool between sections, but the problem remained on the same section. The load-check valve (the valve with the ball located under the spool section) was removed and inspected, but not swapped between sections. I also swapped the pressure compensator between sections, however this did not change the situation.
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