Universal Calibrating Machine
(UCM) Manual
(PM-5201)
Morehouse Instrument Company, Inc.
1742 Sixth Ave., York, PA 17403-2675 USA
Phone: (717) 843-0081
www.mhforce.com
Page 30
Rev. 11/2021
6.3 Service Instructions for Hydraulic Hand Pump
When changing o-rings, always lubricate the o-rings and all contacting metal parts before attempting assembly.
For a lubricant, use the same fluid as will be used in the system. The high-pressure valve and retaining parts
are held in place by the retaining plug (57). To reassemble, screw the retaining plug (57) into the body until all
parts are solid, then back it off about two turns. This provides sufficient travel for the poppet.
The valve rod (41) is held in place by three parts (25, 26, and 27) that must be removed to enable disassembly
of the valve rod. Access to these three parts is gained by removing the reservoir (2). Drain the hydraulic fluid
before removing the reservoir. The piston and hand lever can be removed as an assembly. Unscrew the cylin
-
der retaining plug (16), disconnect from clevis (19), and pull straight up. At the end of the pressure stroke, the
piston should bottom on the body plate (50) before the lever hits the cylinder retaining plug (16). If it does not,
or more finger room between the hand lever and reservoir is desired, loosen piston pin (7), insert a small rod
in the cross hole provided in the piston, and back off the piston, which is threaded into the piston pin (17) as
needed. Re-tighten the setscrew (7).
The cylinder pump (18) must be removed and reassembled from the top. If it is not, the o-ring will be cut by
the angular, intersecting body casting bore. To remove the cylinder, detach the body plate (50) and push the
cylinder from the bottom. On reassembly, lubricate the o-rings and try to rotate the cylinder, as inserted, to
avoid cutting or pinching the o-rings. A tapered piece of wood is helpful in rotating the cylinders.
The precision pressure adjustment mechanism can be unscrewed from the pump body as a unit. The star
wheel (21), star wheel pin (22), piston cap (23), and piston (24) make up a sub-assembly, which is removed
from the pump body by unscrewing the piston body (24). Note that the star wheel (21) is attached to the Ver
-
nier piston (58) by means of a pin (22).
6.4 Repair
All parts of the calibrating machine, except o-rings, are designed to last indefinitely in normal use. If inadver
-
tent misuse or accidental damage occurs, then repair may be accomplished by replacing the damaged parts.