Canon imageRUNNER ADVANCE C5000 Series Technical Workbook page 122

Field remedy
Prepare the tension spring (FU8-2272) to replace according to the steps below:
1) Open the front cover of the finisher, and pull out the saddle unit[1] about 20cm.
2) Pull out auxiliary caster[1] toward the direction indicated with an arrow, and pull out the saddle unit toward
the direction indicated with an arrow.
3) Unlock the stopper[1] of the rail to pull it out about 5cm.
pg. 120