How to repair the hydraulic stepless feed of Shanghai m 1432b universal cylindrical grinder workbench?

The causes and repair methods of hydraulic stepless speed change feed on the worktable of Shanghai m 1432b universal cylindrical grinder are as follows:

(1) The parallelism between the bus bar and piston rod on the upper side of the hydraulic cylinder and the guide rail of the lathe bed and workbench is out of tolerance. The parallelism error between the upper bus of hydraulic cylinder and piston rod and the guide rail of lathe bed and workbench should be corrected according to the assembly requirements.

(2) The hydraulic cylinder is worn and deformed. Hydraulic cylinders should be repaired or replaced by honing.

(3) The lathe bed and workbench guide rail are worn or the contact points with scraping are uneven, and there are too few contact points. Check the contact point and surface roughness between the lathe bed and the workbench guide rail. Requirements: scraping contact point > 16 points /(25mm×25mm), and the surface roughness reaches ra1.6 μ m. ..

(4) The clearance between the piston and the hydraulic cylinder is too large and there is leakage. It should be assembled as a piston, and the clearance between it and the hydraulic cylinder should be 0.04 "0.06 mm.. ..

(5) The reversing valve is worn and leaked. Check the wear of reversing valve and valve hole, and repair or replace it accordingly.

(6) Air enters the hydraulic system. Air in the system should be removed, and air should be avoided at each pipe joint.