Johnston VM502, Maintenance Manual

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MA6:3
V Range 502
l
652
l
802 Maintenance Manual
Johnston Sweepers Limited
Chapter - Wearing Items
Refitting
Replacement is reverse procedure, taking note of the following.
Lightly grease the fan drive spline, using Kluber paste before refitting the impeller.
VT Range : If setscrews are fitted replace with Tuflock Capscrews and torque up the three impeller
securing bolts to 85 Nm.
VS Range: If a setscrew is fitted replace with a Tuflock Capscrew and torque up to 101Nm.
From July 2009 all impellers have a ‘’V ’ ’ mark (C) at Top Dead Centre (TDC) applied when they are
manufactured. When fitting a replacement impeller it should be rotated so this mark is at the 12 o’clock
(TDC) position before fitting the impeller to the shaft. Once fitted ensure the retaining bolts/bolt are
tightened to the prescribed torque.
Intake Duct Flap
When the flap plate is in the open position, it is abraded by the material
discharging from the intake duct into the body. The flap should be
inspected periodically and replaced when worn. To inspect one must
first open the rear door and suitably prop open, then depressurise the
air system in the systems locker, this will allow the flap to be opened
and closed manually from the interior of the body. Enter body and
inspect the flap valve plate which is secured to actuating fingers by a
pair of spring clips.
Removal
To remove a flap plate the springs must be withdrawn using a suitable tool or bar. Notice how the
springs were fitted from each side of the finger guide and around the groove in the finger assembly.
Once the springs are removed the flap plate can be detached from the finger.
Refitting
Before refitting or fitting a new flap plate, ensure the springs are in good condition and the finger
adjustment areas have been cleaned, then locate flap on the finger and replace springs. Ensure the
flap plate seats correctly on top of the inlet tube, if not, check for excessive wear on the inlet tube/flap,
or adjustment of the flap operating mechanism.
M02MA-046
CAUTION:
When replacing a fan impeller, always fit new securing screws. Never re-use existing
hardware.
Never use a second-hand or a non-Johnston fan.
The fan impeller is supplied complete with the hub.
Do not remove the hub or replace it, as the balancing will be adversely affected.
Strictly adhere to the regular checking routines as outlined in the Johnston Operator’s
Guide.
Refit fan case cover (B) using sealant part number 94-1, to the mating face having first removed the old
sealant. Push the fan assembly towards the drive motor and then pull towards you. If there is excessive
play the bearings will require replacement.
Refit the fan inspection plate (A) using sealant as for item 1.
An inspection cover (D) is provided to measure the fan speed by optical tachometer if required.