<p>This study investigates failure analysis and design improvements for a linear rolling guide (LRG) support device in a heavy-duty rack and pinion hydraulic actuator. Premature crushing failure of the end rollers in the LRG support device was observed during prototype field testing. In order to identify the underlying causes, a high-fidelity finite element model of the rack and pinion hydraulic actuator and the LRG support device was established and subjected to numerical analysis. The results indicate that the LRG roller failure is intrinsically governed by non-uniform load distribution in both the longitudinal and transverse directions, leading to excessive local contact stresses at the end rollers, rather than by local material deficiencies or manufacturing defects. On this basis, two improved support schemes of sliding and track roller support devices were proposed. Comparative verification via finite element analysis demonstrates that both improved schemes can significantly reduce contact stress levels. The sliding support device achieves the lowest stress due to its substantially increased effective contact area, whereas the track roller support exhibits superior load distribution characteristics. This study provides a theoretical foundation and practical engineering reference for failure analysis and structural design of support devices in heavy-duty rack and pinion hydraulic actuators.</p>