WHEELS A N D TIRES
Sec. 10
Page 58
Figure 3 — B u d d Type D a m a g e d or Broken Studs
D am aged Inner or Outer Cap Nuts (F ig. 4)
When th is condition is found - it is a definite
indication of a lo o se mounting condition. Cap nuts
and stu d s, if n e c e ssa r y , m ust be replaced. If wheel
b all s e a ts a re damaged, the w heel a lso should be
rep laced .
F r e ezin g of Nut
T his condition r e s u lts from one of two b a sic
cau ses:
1. C orrosion or gallin g of the stud and nut
a sse m b ly can reach a point w here rem oval of cap
nuts is difficult. If th is is a p e r siste n tp r o b le m , the
th read s of the stud and the threads of the inner
cap nut should be clean ed with a w ire brush.
To further aid in th is problem , u se cadm ium
p lated cap nuts with a dichrom ate dip.
2. Im proper tightening of the inner cap nuts.
If the inner nut, during a ssem b ly , is UNDER
TIGHTENED to only 200-250 foot-pounds, and then
the outer tightened c o rrectly to 500-550 foot
pounds, the very act of backing off the outer nut
w ill so m e tim e s turn the inner.
CAST WHEEL STUDS
CAUTION: Insufficient wheel stud
nut torque can cause rim slippage, result
ing in broken valve stems, worn parts,
wheel shimmy and extreme tread wear.
Excessive mounting torque can cause
damage by stripping studs, collapsing
spacer bands, out-of-round rim condition
or broken studs or cracks in the stud hole
area.
Figure 4 — B u d d Type D a m a g e d Inner or Outer Cap Nuts
WHEEL INSPECTION (DISC TYPE)
WORN WHEEL STUD HOLES (F ig. 5)
T his condition w ill usu ally be accom panied by
appearance of a shiny worn su rfa ce on w heel fa ce,
indicating that lo o se w h eels w ere moving against
each oth er. If the stud h o les a re out of shape - oval
o r egg shaped - and w here a build-up of m etal is
around them , th ese w h eels m ust be replaced.
CRACKED DISC WHEELS (F ig. 5)
C racks running from hand-hole to stu d -h ole
o r b o lt-h o le to c e n te r-h o le or hand-hole to hand-
hole, or hand-hole to rim , or stud hole to stu d -h ole,
a r e a d irect re su lt of overloading. Check working
load s of a x le s , d iscard dam aged w h eels, check
w h eel studs and com p lete a sse m b ly .
The hub a ssem b ly may have a worn mounting
fa c e as a re su lt of m oving of the inner w heel on
the hub. The studs may have turned in the hub and
worn the stud groove o r the studs may have actual
c ra ck s or b reaks resu ltin g from tfiis condition.
The w heel may have worn ball s e a ts in the stud
h o le s. A ll th ese p o s s ib ilitie s m ust be checked and
a ll dam aged p a rts replaced.
DAMAGED OR CRACKED RIMS
The rim a s shown in figu re 6 has cracked
fro m fatigue and overload . T his type of fa ilu re is
