Note : The pump group needs to be opened
1) For purposes of optimisation of the pump, to change the piston springs already mounted with other springs of a different force
2) After many years of continuous service, to replace certain parts subject to long term wear and tear.
WARNING : The pump group contains approximately 40 millilitres of non-toxic oil. Be sure to have a container or means available for the oil to drain into. It is wise to remove one piston group BEFORE removing the pump body (332) group off the cam shaft (338), and turning the pump around to drain the oil out into an appropriate recipient.
DRAWING: Drawing for maintenance purposes.
Piston group order on each side from the outside of the pump body to the inside :
Gasket lock nuts (322). IMPORTANT! Torque on these nuts on reassembly is +/- 3kg.
Gasket screws (357)
Gasket plates (356)
Gasket washers (355)
Piston gasket seals (354)
Piston guides (353) with piston guide "O" rings (352) on them
Springs (351)
Pistons (350) with bearings (347) mounted on axis rods (348) and spacing rings (349)
Examination of the piston gasket seals (350)
Check for signs of wear and tear, being signs of splits in the rubber or differences in rubber thickness such as may make the diaphragms seem fragile. Replace if necessary.
Examination of the piston guides (353)
Check for signs of wear and tear on the inner surface. This can usefully be done by mov
ing the piston (350) inside the guide (353) and checking for signs of play. Hold the pieces against the light to see if they are visible (especially uneven) spaces between the piston (350) and the guide (353).
Examination of the piston guide "O" rings (352)
These are not moving parts and should not normally require replacement. However, the ring should be replaced if flattened or squashed.
Examination of springs (351)
If the spring appears to have lost some of its force, or in any case where in doubt, replace it. You can (later, if necessary) measure the force of the spring you have removed to see whether it is still in good condition.
Examination of the pistons (350)
Check for signs of wear and tear on the pistons as set out above for the piston guides (353). The pistons are subject to wear and tear over a very long period which normally exceeds ten years of continuous use.
Examination of the piston bearings (347)
The piston bearing groups are subject to wear and tear over a very long period of use. They should only be taken apart where the bearings (347) are showing signs of wear and tear. They need replacing if they do not turn evenly, or if they are showing visible signs of damage or deformation.
BR>Never replace the piston bearings 347 without replacing the axis rods (348)
Examination of the axis rods (348)
The piston axis rods are subject to wear and tear over a very long period of use. They should only be taken apart where the
axis rods (348) are showing signs of wear and tear. They need replacing if they do not turn evenly, or if they are showing visible signs of damage or deformation.
Never replace the axis rods 348 without replacing the piston bearings (347)
Turn the pump body on one flat side to assemble the first piston group.
Make sure the wide, flatter, side of the cam (338) is facing the outside.
Place a complete piston assembly (346) against the cam shaft (338) so that the two profiles of the piston (350) are seated over the cam shaft (338). The roller bearing (347) inside the piston (350) will be resting against the cam shaft (338).
Place the spring (351) over the piston body (350).
Fit the "O" ring (352) into its seat on the smaller side of the guide ring (353) and the gasket seal (354) into its seat on the wider side of the guide ring (353).
Place the guide ring (353) with its smaller side down, on top of the spring (351).
Position the gasket seal plate (356) over the guide ring (353) so that its holes are lined up with those in the main pump body (363).
Exerting pressure with thumb and fingers of one hand to counteract the pressure of the piston spring (351) start engaging the first screw (357) in the pump body (363).
Then initially engage the screw (357) diagonal to the first one.
Then initially engage the remaining two screws (357)
Turn the four screws (357) further until the thread on the piston body (350) protrudes over the profile of the gasket seal plate (356).
Place the more rounded side of the washer (355) over the thread of the piston body (350) so that it rests against the gasket seal (354).
Engage the nut (322) on the thread of the piston body (350) and turn it manually until is starts offering resistance.
Gradually tighten the four screws (357) in turn a few rotations a time so that pressure on the gasket seal plate (356) remains even.
Complete the tightening of nut (322) up to a maximum torque of 3kg.
Complete the tightening of the four screws (357) up to a maximum torque of 2-3 kg.
Make sure the wide, flatter, side of the cam (338) is facing the outside.
Pour in about 40 milliliters of high quality non toxic oil.
Proceed with reassembly of the second piston group as for the first one.