To Renew Main Bearings And Thrust Washers - Perkins 4.108 Workshop Manual

CRANKSHAFT AND MAIN BEARINGS-H.2
H3
To Renew Main Bearings and Thrust Washers
Removal of the main bearings and thrust washers can
be carried out without removing the crankshaft by the
following procedure:-
1. Remove the engine from its application.
2.
Remove the sump and suction pipe assembly.
3. Slacken the setscrews which secure the main
bearing caps.
4. Remove completely one of the main bearing caps
and remove the bearing shell from the cap.
5. Remove the top half of the bearing shell by push-
ing it, on the opposite side to the one having the
locating tag, with a suitable strip of wood and
rotating it on the crankshaft as shown in Fig. H.1.
6. Inspect the bearing shells and if replacements are
necessary continue by lightly lubricating and in-
serting the new top half bearing shell, plain end
first, into the side having the tag location.
H5
H4
7. Rotate the bearing shell on the crankshaft until it
locates correctly with the tag in the machined slot.
8. Locate the lower half bearing shell in the main
bearing cap, liberally lubricate and refit.
9. Tighten the two securing setscrews to positively
locate the bearing shells then slacken a turn or
two.
10. Repeat items 3-8 for the remaining two bearings.
NOTE: To enable the rear main bearing cap to be
removed, first remove the two oil seal housing
setscrews as shown in Fig. H.3.
11. Finally tighten the main bearings to the torque
given on Page B.2.
Renewal of the thrust washers is accomplished by
carrying out the following procedure:-
1. Remove the two setscrews securing the two rear
main bearing oil seal half housing as shown in
Fig. H.3 and remove the half housing from the
bearing cap.
2. Remove the rear main bearing cap securing set-
screws.
3. Remove the rear main bearing cap and from it the
two lower half thrust washers. (Refer Fig. H.4).
4. The single upper half thrust washer is removed by
rotating it with a thin piece of wood until it can be
I ifted out of its recess.
NOTE: The new thrust washers should be lightly
lubricated before fitting. The steel faces of the
lower thrust washers should face inwards towards
the bearing cap, (Refer Fig. H.5), the steel face
of the upper thrust washer should also face in-
wards.
5. Locate the upper thrust washer half as shown in
Fig. H.6, place the lower halves either side of the
rear main bearing cap as described and refit the
cap.
6. Tighten the setscrews evenly and finally to the
torque given on Page B.2.