Benjamin B Friendswood , TX October 04, 2018 Appliance: Poulan Trimmer/Weedwacker SST250 Poulan Grass Line Trimmer Sst250: My SST25 weed eater had a worn crankshaft and the piston rod on both ends had failed bearings. How to replace Assy C'case. I replaced the assembly case and piston and rod. I reinstalled new parts and the weed eater operates fine. 5 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: 2+ hours