Sun Pumps SPB 10-16C-1.0 - Manual (Page 4)

If extreme pitting or sharp edges, replace piston.
3. Examine cup for wear, cracking, tearing or separation from the piston. If worn
replace and lubricate before installing on piston.
Note cup installation: Wipe cup inserter with oil. Slip back-up ring (when used)
onto piston. Push cup over inserter and square with all surfaces. Faulty cup
installation causes premature cup failure. Some models use a one-piece piston
assembly. The cup does not separate from the piston. Replace entire assembly.
Lubricate piston assembly and slip piston-cup assembly onto piston rod with lid
facing discharge.
4. Next replace Piston Spacer and Retainer on rod.
5. Replace washer; thread on nut and torque per chart.
Note: Always replace with new stainless steel cotterpin and turn ends under.
6. Examine cylinder walls for scoring or etching which causes premature wear of cups
and replace as needed.
7. Lubricate cylinder and replace o-rings and/or back-ups rings if worn or damaged.
Back-up rings go to low pressure side of the o-rings. Carefully slip cylinder
over rod ends and push into inlet manifold with back-up ring to the discharge,
stroke marking on the inside of cylinder to the crankcase.
8. Position discharge manifold onto pump as described, replace fasteners and torque
per specifications chart.
SLEEVED-TYPE PISTON MODELS
DISASSEMBLY
1. After removing the discharge manifold, slip cylinders off piston rods. It is best
to leave the cylinder adapters and springs in the inlet manifold as they may score
the sleeved-type pistons when removed. The V-packings will remain in the cylinders.
2. Press worn V-packings from cylinders.
3. Remove cotter pins, slotted nuts, washers and piston retainers. Pull sleeved-type
pistons from each piston rod. Next slip sleeved-type spacer and inlet valve from each
piston rod.
4. Lubricate and install new o-rings on cylinders and adapters.
5. Inspect inlet valve surfaces. If inlet valves are worn, lap with 240 grit paper or
replace if evidence of excessive damage. If sleeved-type piston inlet surface is worn
or the outer diameter is scored, replace it.
REASSEMBLY
1. First install inlet valve then sleeved-type piston onto piston rod with the lapped end
toward the inlet valve.
2. Next install the sleeved-type spacer.
3. Then install new V-packings in the cylinder in the following order:
a. Install all parts in one cylinder, and then move to the next cylinder.
b. Rotate crankshaft to extend one piston rod completely forward.
c. Lubricate V-packings and cylinder I.D. and place O-ring end of cylinder on
work surface.
d. Install into cylinder Female Packing Spacer, black Female Adapter, V-packings,
nylon Male Adapter and Male Packing Spacer with “V” side down.
e. Install spring in outer end of cylinder and slip cylinder assembly over piston rod
end. Press cylinder into manifold chamber. The spring in the cylinder will be in