Greenlee 7904SB QUICK DRAW 90 Handbuch Seite 11

Maintenance (cont'd)
Ball Seat Repair
Re-seating:
Minor seat imperfections may be corrected by
re-seating. Use a soft brass rod and hammer to
tap the ball against its seat.
Wear eye protection when
servicing this tool.
Failure to wear eye protection can
result in serious eye injury from
flying debris or hydraulic oil.
Re-drilling:
Badly worn or damaged seats may be reworked by
re-drilling and then re-seating.
The pump block is manufactured with seats of 118˚,
the standard drill point angle; use standard drills for
re-drilling.
• To re-drill the 7/32" ball seat for release stem (28):
Use an "I" drill and a 9/64" diameter reamer.
• To re-drill the 7/32" ball seat for the discharge check:
Use an "I" drill and a 5/32" diameter reamer.
• To re-drill the 3/16" ball seat for the intake check:
Use a 1/4" drill and a 1/8" diameter reamer.
When drilling; remove a minimum of material to obtain
maximum seat life. Re-seat the balls before reassembly.
"I" DRILL
STD. DRILL
ACCEPTABLE
"I" DRILL
RELEASE
VALVE
STEM
"B" DRILL
9/64" REAM
Greenlee Textron / Subsidiary of Textron Inc.
7904SB/7906SB Hydraulic Punch Driver
DISCHARGE
CHECK
5/32" REAM
9/64" REAM
INTAKE
CHECK
Reassembly
Reassembly is done in reverse sequence of disassembly.
Inspect all O-ring seals for cuts and wear; replace as
needed.
Reassembly—Ram Section
1. Lightly coat ram (3) and cylinder (1) seals, and both
bores of the cylinder with clean oil.
2. Push ram completely into cylinder.
3. Thread installation rod into tapped hole in the ram
and install compression spring (7). Place spring
retaining plate (4) on top of spring (7) so the instal-
lation rod passes through the 1/4" hole in the
retaining plate.
4. Place a flat washer and thread a hex nut on the
installation rod. Tighten the nut until spring retaining
plate slides past the retaining ring groove. Install
the two retaining rings (5) 180° apart. Remove
installation rod.
Installation
Rod
Installation Rod (Steel)
Reassembly—Pump Section
Fill plunger (24) bore with clean hydraulic oil. Coat
O-ring seals on plunger with clean oil and reinsert
the pump block (2) with release valve knob (27) closed.
11 4455 Boeing Dr., Rockford, IL 61109-2988 815/397-7070
Retaining Rings
Flat Washer & Nut
Spring Retaining Plate (4)
Compression Spring (7)
Cylinder (1)
Ram (3)
#10-32 Thread
1
3 /
2