DS 19 OPERATION No. DS 231-3 : Overhauling of a water pump and low pressure pump. Op. DS 231-3 149
TOOLS
6 Remove the pump from the stand. Remove the spindle and impellor assembly (17) from the water pump body.
Remove the thrust washer (18), the ring seal (19) and the cup (20) from the pump body. Remove the spring
(21), the cyclam joint (22) and the spindle thrust washer (23).
Remove the greaser and the overflow unions (24) and (25).
IMPORTANT REMARK - In order to make sure of perfect sealing after a complete pump overhaul, it is necessary
to lap the thrust washers (26) and (27) and the thrust face on the pump of the joint (22). The lapping of the
washers is carried out with extremely fine emery powder. In order to avoid impregnating the porous bronze
bush (28), it must be removed.
This delicate operation demands great care in order to avoid damage to the pump body.
7 Lapping the thrust washers
Before doing anything else, the pump body must be very carefully cleaned, in order to eliminate every trace of
grease or oil.
Use alcohol only. Blow with compressed air especially in the bores, the greaser hole and the oil-way between
the pump body and grease retainer.
Two conditions are possible
a) If the thrust washer (27) is in good condition and only’ requires grinding, remove the bronze bush, using the
threaded extractor 2291-T (see Pl. 39, fig. 3). Screw the thread in the bush, then turn the pump body and . . . Extractor 2291-T
press out the assembly on a press with a round bar Drift = 14 dia.
Length = 150 mm.
b) If the thrust washer (27) is to be replaced, it is necessary to dismantle the bush and washer assembly with heat
(see paragraph 1 below).
1. For the water pump body
Heat the body of the water pump to 200
0
C (400
0
F) approximately.
Use a furnace for preference or failing this, form a tunnel with fire bricks, then heat the fire bricks
with a blow pipe. When the bricks are hot, put the pump body in the tunnel.
An indication that the correct temperature is attained is when a wood shaving projecting from the pump
body begins to blacken.
Avoid direct heat which will deform the parts.
Push out the bush and thrust washer in a press. Let the parts cool off. (The bush and washers are to be
replaced) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mandrel :
Large dia. = 18.5
2. For the low pressure pump body Small dia. = 14.9
Do not remove the thrust washer, unless it is necessary (deep scratches). Heat the body of the pump in Length = 150 mm
the same manner as for the water pump body. When the correct temperature is reached, tap lightly on the
pump body, bearing side, with a piece of wood, the thrust washer should drop out.
8 Carefully clean the parts..
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