GMC C Series 1993, Repair Manual

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V8 ENGINES, GASOLINE 6A2-41
A
D R I L L H O L E T O
P R O P E R S I Z E
B
T A P H O L E T O
P R O P E R S I Z E
I N S T A L L I N S E R T
O N M A N D R E L
D
I N S T A L L I N S E R T I N T O
N E W L Y T H R E A D E D
H O L E V1195
F i g u r e 8 5 — R e p a i r i n g T h r e a d H o l e s
THREAD REPAIR
Damaged threads may be reconditioned by drilling
out, rethreading and installing a suitable thread insert.
Tools Required:
General purpose thread repair kits are available
commercially.
C A U T I O N : W e a r s a f e t y g l a s s e s t o a v o i d e y e
d a m a g e . 1
1. Determine size, pitch, and depth of damaged
thread. If necessary, adjust stop collars on cutting
tool and tap to required depth.
3. Tap hole. Lubricate tap with light‘engine oil. Clean
the thread.
I m p o r t a n t
• Avoid build-up of chips. Back out the tap every
few turns, and remove chips.
4. Thread the . thread insert onto the mandrel of the
installer (figure 85). Engage the tang of the insert
onto the end of the mandrel.
5. Lubricate the insert with light engine oil (except
when installing in aluminum) and install.
9
I m p o r t a n t
I m p o r t a n t
• Refer to the kit m anufacturer's instructions
regarding the size of drill and tap to be. used.
2. Drill out damaged thread. Clean out chips,,
• When correctly installed, the insert should be
flush to one turn below the surface.
6. If the tang of the insert does; not break off when
backing out the installer, break the tang off with a
drift.