Galvanic Corrosion; Electric Welding; Starting With Auxiliary Battery - Volvo MD2010 Workshop Manual

Galvanic corrosion

MD201OB/C, MD2020B/C, MD203OB/C, MD204OB/C
The engine's flywheel housing and transmission (re-
verse gear/S-drive) are electrically insulated from the
engine. Note the fitting sequence on the screw union
(Fig. 113). The insulation sleeve pos. 1 is only fitted on
one of the screws (optional screw).
WARNING! The flywheel housing or transmission
Q
(reverse gear alt. S-drive) must under no circum-
stances be earthed. Earthing of these compo-
nents can result in serious damage as a result of
galvanic corrosion.
Fig. 113. Electrical insulation (A) of the flywheel hous-
i ng and transmission
1. Insulation sleeve 2. Insulation washer
3. Washer

Electric welding

Remove the plus and minus leads from the batteries,
and then remove all cables to the alternator.
Always connect the welding clip to the component
which is to be welded and as close to the weld point as
possible. The clip must never be connected to the en-
gine or so that the current can pass over a bearing.
On completion of welding: Always connect the
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cables to the alternator before the battery leads
are replaced.
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Repair instructions

Starting with auxiliary battery

,u -umfi~ i WARNING! The batteries (especially the auxiliary
J
battery) contain oxyhydrogen gas which is very
-
explosive. A spark, which can occur if the auxili-
ary battery is incorrectly connected, is sufficient to
cause the battery to explode and result in injury.
Note: If the start battery has frozen it must be thawed
first before a start attempt is made with the auxiliary
battery. Check that the battery is not damaged before
connecting it again.
1.
Check that the auxiliary battery's rated voltage cor-
responds to the engine's system voltage (12V).
2.
Connect the red auxiliary lead (+) to the auxiliary
battery and then to the flat battery. Then connect
the black auxiliary lead (-) to the auxiliary battery,
and finally to a point some distance from the flat
batteries, e.g. at the main switch on the minus lead
or at the minus lead's connection on the starter mo-
tor (2-pole electrical system), or at the minus lead's
connection on the engine (one-pole system).
3. Start the engine. NOTE! Do not touch the con-
nection during the attempt to start (risk for
sparks) and do not lean over any of the bat-
teries.
4. Remove the leads in exactly the reverse order to
the way they were connected. NOTE! The ordin-
ary leads to the standard battery must absolute-
l y not be disconnected.
Electrical system
7 1