Fault Phenomenon: SANY SAP90C paver a loud impact sound occurs when the screed reaches the top of its lift.

Troubleshooting Process:
– Checked cushion valve: internal cylinder cushion spool stuck.
– Checked piston: cushion plunger worn.
– Checked operation: lifting speed too fast.
– Checked oil quality: contaminated fluid.

Root Cause: The mechanical cushion valve inside the screed lift cylinder failed due to debris, unable to decelerate at the end of the stroke.

Required Parts: Screed lift cylinder repair kit or cylinder replacement.