Hummer H2. Manual - part 83

VACUUM BOOSTERS 

Vacuum Boosters 

Alignment incorrect 

B 

Require repair or replacement. 

Bent 

B 

Require replacement. 

Contaminated, affecting performance 

A 

Require repair. Identify and correct cause. 

Cracked 

B 

Require replacement. 

Loose 

A 

Require replacement of worn parts. 

Missing 

C 

Require replacement. 

Number of teeth incorrect 

B 

Require replacement. 

Teeth broken 

A 

Require replacement. 

Teeth damaged, affecting performance 

A 

Require replacement. 

Condition 

Code 

Procedure 

Applies too much assist (oversensitive) 

A 

Require replacement. 

Attaching hardware broken 

A 

Require repair or replacement of 

hardware. 

Attaching hardware missing 

C 

Require replacement of hardware. 

Attaching hardware not functioning 

A 

Require repair or replacement of 

hardware. 

Auxiliary vacuum pump inoperative 

A 

Require repair or replacement. See 

note below. 

NOTE: Inoperative includes intermittent operation or out of OEM specification. 

Check valve grommet deteriorated, affecting 
performance 

A 

Require replacement of grommet. 

Check valve grommet deteriorated, not 
affecting performance 

1 

Suggest replacement of grommet. 

Check valve inoperative 

A 

Require repair or replacement. See 

note below. 

NOTE: Inoperative includes intermittent operation. 

Check valve leaking 

A 

Require replacement of check 

valve. 

Check valve missing 

C 

Require replacement of check 

valve. 

Check valve noisy 

2 

Suggest replacement. 

Connector broken 

A 

Require repair or replacement. 

Connector (Weatherpack type) leaking 

A 

Require repair or replacement. 

Connector melted 

A 

Require replacement. See note 

below. 

NOTE: Determine cause and correct prior to replacement of part. 

Connector missing 

C 

Require replacement. 

 

1998 Chevrolet Pickup C1500 

Uniform Inspection and Communication Standards BRAKE SYSTEMS

  

VACUUM HOSES 

See Hoses.  

VALVES 

Valves 

Leaking 

A 

Require replacement. 

Terminal burned, affecting performance 

A 

Require repair or replacement. See 

note below. 

NOTE: Determine cause and correct prior to repair or replacement of part. 

Terminal burned, not affecting performance 

2 

Suggest repair or replacement. 

Terminal corroded, affecting performance 

A 

Require repair or replacement. 

Terminal corroded, not affecting performance 

2 

Suggest repair or replacement. 

Terminal loose, affecting performance 

B 

Require repair or replacement. 

Terminal loose, not affecting performance 

1 

Suggest repair or replacement. 

Threads damaged 

A 

Require repair or replacement. 

Threads stripped (threads missing) 

A 

Require replacement. 

Vacuum hose filter leaking 

A 

Require replacement of filter. 

Vacuum hose filter restricted 

A 

Require replacement of filter. 

Wire lead burned 

A 

Require repair or replacement. 

Wire lead conductors exposed 

B 

Require repair or replacement. 

Wire lead open 

A 

Require repair or replacement. 

Wire lead shorted 

A 

Require repair or replacement. 

Condition 

Code 

Procedure 

Attaching hardware broken 

A 

Require repair or replacement of hardware. 

Attaching hardware missing 

C 

Require replacement of hardware. 

Attaching hardware not functioning 

A 

Require repair or replacement of hardware. 

Leaking 

B 

Require repair or replacement. 

Linkage bent (rear load valves) 

A 

Require repair or replacement of linkage. 

Linkage broken (rear load valves) 

A 

Require repair or replacement of linkage. 

Linkage disconnected (rear load 
valves) 

C 

Require repair or replacement of linkage. 

Pressure out of specification 

B 

Require adjustment. If not possible, require 

replacement. 

Seized 

A 

Require replacement. 

Sticking 

A 

Require repair or replacement. 

Terminal burned, affecting 
performance 

A 

Require repair or replacement. See note 

below. 

 

1998 Chevrolet Pickup C1500 

Uniform Inspection and Communication Standards BRAKE SYSTEMS

  

WHEEL ATTACHING HARDWARE 

For conditions noted below, also check condition of wheel stud holes.  

Wheel Attaching Hardware 

NOTE: Determine cause and correct prior to repair or replacement of part. 

Terminal burned, not affecting 
performance 

2 

Suggest repair or replacement. 

Terminal corroded, affecting 
performance 

A 

Require repair or replacement. 

Terminal corroded, not affecting 
performance 

2 

Suggest repair or replacement. 

Terminal loose, affecting 
performance 

B 

Require repair or replacement. 

Terminal loose, not affecting 
performance 

1 

Suggest repair or replacement. 

Threads damaged 

A 

Require repair or replacement. 

Threads stripped (threads missing) 

A 

Require replacement. 

Wire lead burned 

A 

Require repair or replacement. 

Wire lead conductors exposed 

B 

Require repair or replacement. 

Wire lead open 

A 

Require repair or replacement. 

Wire lead shorted 

A 

Require repair or replacement. 

CAUTION: Proper lug nut torque is essential. Follow manufacturer's torque 

specifications and tightening sequence. DO NOT lubricate threads unless 
specified by the vehicle manufacturer. 

Condition 

Code 

Procedure 

Bent 

A 

Require replacement. 

Broken 

A 

Require replacement. See note below. 

NOTE: Some manufacturers require replacement of all studs on any wheel if two or 
more studs or nuts on the same wheel are broken or missing. 

Loose 

B 

Require repair or replacement of affected 

component. 

Lug nut flats rounded 

A 

Require replacement of nut. 

Lug nut installed backward 

B 

Require repair. 

Lug nut mating surface 
dished 

A 

Require replacement of nut. 

Lug nut mating type 
incorrect 

B 

Require replacement of nut. 

Lug nut seized 

A 

Require replacement of nut and/or stud. 

 

1998 Chevrolet Pickup C1500 

Uniform Inspection and Communication Standards BRAKE SYSTEMS

  

WHEEL BEARINGS, RACES, AND SEALS 

Wheel Bearings, Races, and Seals 

WHEEL CYLINDERS 

You are not required to replace or rebuild wheel cylinders in axle sets. However, when rebuilding or replacing a 
wheel cylinder due to the conditions that follow, you may suggest rebuilding or replacement of the other wheel 
cylinder (on the same axle) for preventive maintenance, for example, the part is close to the end of its useful 
life.  

Determine the need to rebuild or replace based upon the individual wheel cylinder conditions that follow.  

Wheel Cylinders 

Stud incorrect 

B 

Require replacement of stud. 

Threads damaged 

A 

Require repair or replacement of component with 

damaged threads. 

Threads stripped (threads 
missing) 

A 

Require replacement of component with stripped 

threads. 

NOTE:

When replacing or repacking wheel bearings, grease seal replacement is 
required . You are not required to replace these components in axle sets. 
Determine the need to replace based upon the individual component conditions 
that follow. 

Condition 

Code 

Procedure 

Axle seal on drive axle leaking 

A 

Require replacement of seal and inspection of 

axle, bearing, housing, and vent tube. 

Bearing end-play exceeds 
specifications 

B 

Require adjustment of bearing, if possible. If 

proper adjustment cannot be obtained, require 

replacement of bearing and race assembly. 

Bearing rollers, balls or races are 
worn, pitted, or feel rough when 
rotated as an assembly 

B 

Require replacement of bearing and race 

assembly. 

Seal leaking 

A 

Require replacement of seal and inspection of 

bearings. See note below. 

NOTE: Require inspection of mating and sealing surface and repair or replace as 
necessary. Check vent. A plugged vent may force fluid past the seal. 

Seal missing 

C 

Require replacement. 

Spindle worn 

B 

Require replacement of spindle and bearings. 

Condition 

Code 

Procedure 

Attaching hardware bent 

B 

Require replacement of bent parts. 

Attaching hardware broken 

A 

Require repair or replacement of hardware. 

 

1998 Chevrolet Pickup C1500 

Uniform Inspection and Communication Standards BRAKE SYSTEMS