MTS Series 322 Load Frames - Manual (Page 69)

Series 322 Load Unit Maintenance 69
Load Unit: Bleed the Hydraulic Lift Cylinders
Bleed both hydraulic lift cylinders whenever the crosshead does not move
smoothly. Also bleed them whenever the sealed side of the hydraulic system has
been opened to air. The following figure shows the location of the bleed ports for
the two types of lifts commonly used.
The crosshead can slowly drift down the columns if the locks are turned off
and the hydraulic pressure is turned off.
The crosshead can damage any test fixtures, grips, and specimen in its
path.
Unlock the crosshead only to reposition it. Always lock the crosshead after you
have repositioned it, and never leave the crosshead unlocked.
1. Make sure your crosshead is locked.
2. Turn on system electrical power.
3. Reset any active interlocks at the test controller.
4. Turn on high hydraulic pressure.
Bleed ports
CAUTION