Section F Transmission
9803/8550
Section F
Tyres and Wheels
1 - 5
Wheel Hub Assembly
Removal
It is assumed that roadwheels are removed and the machine
is correctly supported.
Drain the oil from the chain case via plug A.
Slacken nut B and remove bolts C (4 off). Remove hub
adjustment bolt and nut and swing the hub assembly
towards the centre of the machine so that the drive chain is
at its slackest. Use a suitable bar to wedge the hub as
shown at X.
Note: If the front hub is to be removed, both hubs on that
side must be rotated to slacken both chains.
Remove cover plate G and remove the spider (see Drive
Motor Removal, Section E). Lift off the appropriate chain
from the drive sprocket. Note that the front hub is driven by
the inner chain, therefore the rear chain will need to be lifted
off first.
Remove the nut B and pull the hub assembly out; remove
the chain from the sprocket 2. Remove the hub assembly
from the chassis. Remove and discard seal 9.
Replacement
Replacement is a reversal of the removal procedure.
A new 'O' ring 9 must be fitted. Apply a thin smear of silicon
sealer to the groove before fitting the ‘O’ ring, this will retain
the ring in the groove. Smear the hub mounting face and ‘O’
ring with JCB HP Grease.
Adjust the drive chain(s) as follows:
a Mount the hub onto the machine and fit nut B finger
tight only.
b Position adjustment bolt and nut into the slot in the
adjustment bracket as shown at Y. Use the bolt to push
the hub away from the centre of the machine and so
tighten the chain.
c Rotate the sprocket so that one side of the chain is taut.
Position the hub to give 25 mm (1 in) of slack on the
opposite side of the chain at the midway point.
d When the correct tension is achieved, fit and tighten
bolts C and tighten nut B.
Finally torque tighten nut B and bolts C to 244 Nm (180
lbf ft,
25 kgf m).
Note: The drive chains are pre-tensioned during
manufacture and do not require routine adjustment in
service.
Refill the chain case with the correct oil at point D.
Dismantling
The numerical sequence is a guide to dismantling.
Note: Stub axle 4 is fitted to rear hubs and 4A to front hubs.
Spacer 3 is only fitted to rear hubs.
Remove bolts 1 (6 off) and drive sprocket 2. Support the
assembly on face Z and press out the stub axle assembly 4
or 4A. Bearing 5 will remain in the casing 8 and can be
removed separately if necessary. The bearing cap of bearing
6 will also be left in the casing and can be removed if
necessary. Shaft seal 7 should be removed from the stub
axle 4 and discarded. Examine the stub axle and casing for
wear or damage.
Assembly
The numerical sequence shown in the dismantling
procedure should be reversed.
Lubricate all bearings and seals with JCB Special HP Grease
before assembly.
Clean the mating faces of the sprocket and hub before
assembly using JCB Cleaner/Degreaser. Apply JCB Retainer
(High Strength) to the stub axle mounting face and place the
sprocket onto the stub axle.
Apply JCB Retainer (High Strength) to bolts 1. Tighten
evenly to the correct torque in a diagonal sequence whilst
rotating the hub to seat the bearings.
Note: The torque required to rotate the hub after assembly
should be no more than 30 Nm (22 lbf ft, 3 kgf m).
Torque Settings Nm lbf ft kgf m
Drive sprocket bolts 1 (6 off) 405 298 41
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Issue 2*
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