MTS Series 311 Load Frame - Manual (Page 57)

Bleeding the Hydraulic Lift Cylinders
Series 311 Load Frame Maintenance 57
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. Ensure the crosshead is locked.
2. Turn on system electrical power.
3. Reset any active interlocks at the test controller.
4. Turn on high hydraulic pressure.
5. If there is a specimen in the load frame, remove it.
The lifts contain hydraulic fluid under high pressure.
If the bleed port screw is unscrewed all the way, the screw can fly out of its
port at high velocity and it could hurt you or damage your equipment.
Unscrew the bleed port screw no more than 1/2 turn to vent the trapped air.
Open to Bleed
6. Use a 1/8 inch hex key (or slotted screwdriver, depending on model number)
to open one of the bleed ports.
Do not unscrew the bleed port screw more than 1/2 turn.
CAUTION
WARNING