AIR COMPRESSOR - MIDLAND BRAKE MODELS EL.1300, EL-1600
Examine unloader components for excessive wear or
deformation. Parts which do not conform to standards
as noted in SPECIFICATIONS in this Section should be
Inspect unloader spring for loads at specified heights.
Visually check unloader pins for damage and measure
Pistons must be inspected for damage, such as cracks
or scoring. Measure outside diameter of both pistons
just below the compression ring grooves; then compare
this diameter with inside diameter of respective cylinder
bore. Be sure to measure the piston at 90 degree angle
to piston pin bore to insure correct measurement.
If piston diameter is more than .020 cm (.008 in.) smaller
than cylinder bore, the piston must be replaced. Service
pistons are available in .051 cm (.020 in.) oversize.
Piston pins must have a light interference fit in piston and
a slip fit in the rod. Check fit of compression and oil
rings in grooves of pistons and measure clearance.
Position each ring in respective cylinder bore and
measure ring gap as shown in Figure 9. Refer to
SPECIFICATIONS in this Section for ring gap limits and
ring groove clearance. Rings must be replaced if not
within specified limits.
Figure 9 - Measuring Piston Ring Gap
Connecting rod bearing inserts must be free of scoring,
pitting or any visible wear. Inspect rod bearing fit on
crankshaft journals. Be sure to check connecting rod
bearing side clearance on crankshaft (Figure 10). Refer
to SPECIFICATIONS in this Section for clearances.
If connecting rod bearing-to-crankshaft clearance is
excessive, new inserts must be installed. If connecting
rod side clearance is excessive, a new rod and bearing
cap must be installed.
Figure 10 - Checking Connecting Rod Side
Check cylinder block for cracks and check inside of
cylinder bores for scratches, scoring, pitting, out-of-round
Out-of-round should not exceed more than .00127 cm
(.0005 in.) or taper not more than .0025 cm (.001 in.)
from top to bottom of bore. If excessive taper or out of
round is found, the cylinder must be rebored and honed
oversize or replaced with a new cylinder block. Service
pistons and ring are available in .0503 cm (.020 in.)
Bent or twisted crankshafts cannot be repaired. If rod
journals are scored beyond repair or worn more than
limits listed in SPECIFICATIONS, replace the crankshaft
or regrind journals. New insert bearings are available in
.0254 cm (.010 in.) .0508 cm (.020 in.) and undersize.
If a main bearing journal has a sleeve and the journal is
scored beyond repair or worn more than the limits, listed
in SPECIFICATIONS in this Section, the crankshaft must
Threads, keyway, and all ground and machined surfaces
must not be mutilated or worn.
Examine ball bearing for worn or damaged balls; rotate
bearing by hand to detect roughness. If wear,
roughness, or damage is evident bearing must be
AIR COMPRESSOR - MIDLAND BRAKE MODELS EL-1300, EL-1600