Apply multipurpose lubricant (NLGI grade 2 EP) to "U" joints
and slip joint fittings.
INSPECTION
Abnormal vibration and noise can come from many driveline
sources. Drive shaft vibration/noise increases with vehicle speed
(MPH). A vibration that occurs within a specific speed is not caused
by drive shaft imbalance. Before overhauling driveline, check for
other causes/sources of possible vibration/noise.
TIRES & WHEELS
Check tire inflation and wheel balance. Check for foreign
objects in tread, damaged tread, mismatched tread patterns or
incorrect tire sizes. Check for bent wheels.
CENTER BEARING
Tighten drive shaft center bearing mounting bolts. If bearing
insulator is deteriorated or oil-soaked, or drive shaft can be moved
up/down in support, replace center bearing support assembly.
ENGINE & TRANSMISSION MOUNTS
Tighten mounting bolts. If rubber mounts are deteriorated or
broken, replace as needed.
DRIVE SHAFT(S)
Check drive shaft(s) for missing weights, broken welds, or
for dents affecting balance. Check for undercoating, mud, snow/ice on
drive shaft(s). Clean shafts thoroughly and test drive.
"U" JOINTS
Check for foreign material lodged in joints and flange/yokes.
Check for loose "U" joint-to-flange mounting bolts. Check for worn "U"
joint needle bearings. Check for Reddish-Brown rust-dust around "U"
joint caps. Replace "U" joints if necessary.
ADJUSTMENTS
CHECKING DRIVE SHAFT PHASING
One-Piece Drive Shafts
1) Ensure "U" joint flanges on either end of drive shaft are
in same plane. See Fig. 2. Drive shafts with slip joints between yokes
often have arrows to aid in alignment. If yokes are not in same plane,
disassemble slip joint from drive shaft splines. Install slip joint
back onto drive shaft splines, aligning "U" joint yokes. Test drive.
2) Single tube type drive shaft has slip joint on outside of
"U" joint yoke (at transmission end). If one-piece tube type drive
shaft yokes are out of alignment, the drive shaft is torque-twisted.
Drive shaft must be replaced.
CYLINDER BLOCK
* PLEASE READ THIS FIRST *
NOTE: Always refer to appropriate engine overhaul article in the
ENGINES section for complete overhaul procedures and
specifications for the vehicle being repaired.
BLOCK CLEANING
Only cast cylinder blocks should be hot tank cleaned.
Aluminum cylinder blocks should be cleaned using cold tank method.
Cylinder block is cleaned in order to remove carbon deposits, gasket
residue and water jacket scale. Remove oil galley plugs, freeze plugs
and cam bearings prior to block cleaning.
BLOCK INSPECTION
Visually inspect the block. Check suspected areas for cracks
using the Dye Penetrant inspection method. Block may be checked for
cracks using the Magnaflux method.
Cracks are most commonly found at the bottom of the
cylinders, the main bearing saddles, near expansion plugs and between
the cylinders and water jackets. Inspect lifter bores for damage.
Inspect all head bolt holes for damaged threads. Threads should be
cleaned using tap to ensure proper head bolt torque. Consult machine
shop concerning possible welding and machining (if required).
CYLINDER BORE INSPECTION
Inspect the bore for scuffing or roughness. Cylinder bore
is dimensionally checked for out-of-round and taper using dial bore
gauge. For determining out-of-round, measure cylinder parallel and
perpendicular to the block centerline. Difference in the 2 readings
is the bore out-of-round. Cylinder bore must be checked at top, middle
and bottom of piston travel area.
Bore taper is obtained by measuring bore at the top and
bottom. If wear has exceeded allowable limits, block must be honed
or bored to next available oversize piston dimension.
CYLINDER HONING
Cylinder must be properly honed to allow new piston rings to
properly seat. Cross-hatching at correct angle and depth is critical
to lubrication of cylinder walls and pistons.
A flexible drive hone and power drill are commonly used.
Drive hone must be lubricated during operation. Mix equal parts of
kerosene and SAE 20w engine oil for lubrication.
Apply lubrication to cylinder wall. Operate cylinder hone
from top to bottom of cylinder using even strokes to produce 45 degree
cross-hatch pattern on the cylinder wall. DO NOT allow cylinder hone
to extend below cylinder during operation.
Recheck bore dimension after final honing. Wash cylinder
wall with hot soapy water to remove abrasive particles. Blow dry with
compressed air. Coat cleaned cylinder walls with lubricating oil.
DECK WARPAGE
Check deck for damage or warped head sealing surface. Place
a straightedge across gasket surface of the deck. Using feeler gauge,
measure clearance at center of straightedge. Measure across width and
