Cup Plug Replacement - Mack E7 Service Manual

5-101.bk Page 3 Friday, March 17, 2006 11:05 AM
2. Using a wire brush or rotary wheel, remove
any rust, corrosion or other debris from the
block.
3. Clean all other block surfaces with mineral
spirits or other suitable solvent.
4. Using due care and caution, clean and dry
the block with compressed air.
INSPECTION
A complete discussion of the proper methods of
precision measuring and inspection is outside the
scope of this manual. However, every shop
should be equipped with standard gauges such
as bore gauges, dial indicators, outside and
inside micrometers, thickness gauges and
straightedges.
Check the cylinder block for indications of
cracking or coolant leakage. If any damage is
suspected, use a standard dye penetrant or
magnaflux procedure to determine if cracks exist.
A cracked engine block must be replaced and
never reused.
Refer to Figure 6-1.
Using a straightedge (PT5027 or equivalent) and
thickness gauges, check the cylinder head
mounting surfaces for flatness. The cylinder block
mounting surface, on a service block, should be
flat within 0.004 inch (0.102 mm).
Figure 6-1 — Checking Flatness of Cylinder Block Deck
200 ENGINE ASSEMBLY
If the cylinder block is determined to be
serviceable after thorough cleaning and
inspection, reassemble the engine. Use
replacement or original parts, as determined
during component inspection.

Cup Plug Replacement

REMOVAL
Refer to Figure 6-2.
1. Using a hammer and punch, drive one edge
If, after several taps with a hammer, the plug
does not rotate and is being driven inward, stop
tapping. Drill a hole approximately 1/8 inch
(3.2 mm) in diameter in the center of the plug.
Insert a sheet-metal screw in the hole. Leave
enough of the screw protruding from the plug to
allow a pry bar to be inserted under the head of
the screw and pry the plug out.
2. Clean the plug hole(s) with a wire brush or
of the plug inward. The plug should rotate
causing the opposite edge to move outward.
When the edge moves out far enough, grab
it with a pair of pliers and pull it out.
wire wheel. After cleaning, visually check the
surface for cracks. When satisfied that there
are no cracks anywhere in the block, replace
the plug(s).
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