jcb 1CX, Service Manual

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12 - 20
Auxiliary Pump (High-flow machines)
Dismantling and Assembly
Note: Before removing and dismantling the pump, check
flow and pressure. If either of these is low, renewal of
components such as gears, bearings and housings will not
effect a permanent cure. If the pump output is satisfactory
but there is external leakage, the pump may be removed and
dismantled for re-sealing only.
The numerical sequence shown on the illustration is
intended as a guide to dismantling.
For assembly the sequence should be reversed.
When Dismantling
Mark housings and covers to ensure correct re-assembly.
Keep bearing blocks 6, 8, 16, 18 and gears 4, 5, 14 and 15
together in sets to ensure refitting of the bearing blocks in
their original positions.
Extended bush A in bearing block 6 is a light push fit in
flange 2.
DO NOT remove plug B as it is an interference fit,
assembled to a critical dimension.
Inspection
Wash all components then apply hydraulic oil immediately
afterwards to prevent moisture from collecting.
It is normal for the gears to have cut a slight track in the
body bore on the inlet side. The gear track wear cannot be
measured accurately but will be related to bearing wear.
Examine the bores of the bearing blocks 6, 8, 16 and 18
which are coated during manufacture with PTFE. If the grey
PTFE is worn through so that the bronze base is visible, the
complete pump must be renewed.
Renew pump if faces of bearing blocks are scored or if side
faces of gears are chipped or damaged. DO NOT use any
abrasives on the bearing blocks or gears as this would
destroy critical manufacturing dimensions.
When Assembling
Renew all seals. Hold them in position with grease during
assembly. Ensure that the ends of seals 7, 9, 17 and 19 do
not overhang the bearing blocks to become trapped in the
housings.
Bearings must be assembled with cast recesses (not seal
grooves) against gear faces and with seal ends towards the
inlet side of the pump.
Lightly lubricate threads of bolts 1 and finger tighten only.
Hold flange 2 in a vice and apply a force of 200-250 N (45-
55 lbf) to body 3 at position indicated by arrow X (within 10
mm [0.4 in] of the flange). Whilst maintaining this force,
torque tighten bolts 1 in a diagonal sequence. This
procedure is necessary to ensure metal to metal contact
between front bearing lobes and inlet side of body.
Torque tighten bolts 1 to 61 - 68 Nm (45 - 50 lbf ft, 6.2 - 7.0
kgf m).
If the inlet adapters are disturbed, fit new ‘O’ rings and
tighten to 115 - 145 Nm (85 - 107 lbf ft, 11.7 - 14.8 kgf m).
Do not overtighten.
If the outlet adapters are disturbed, clean the threads and
apply JCB Threadlocker and Sealer to two of the threads.
Tighten to 95 Nm (70 lbf ft, 9.7 kgf m). Do not overtighten.
Section E Hydraulics
9803/8550
Section E
*12 - 20
Issue 1*
Pumps
*
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