Hummer H2. Manual - part 78

CALIPERS 

You are not required to replace or rebuild calipers in axle sets. However, when replacing or rebuilding a caliper 
due to the conditions that follow, you may suggest servicing, rebuilding, or replacement of the other caliper (on 
the same axle) for improved performance and preventive maintenance (for example, the part is close to the end 
of its useful life, replacing the caliper may extend pad life, or contribute to more balanced braking).  

Calipers 

Shim (OE standard) missing 

C 

Require replacement. See note below. 

NOTE: Aftermarket shims may be suggested to reduce noise. 

Shim out of position 

B 

Require removal or replacement. See note 

below. 

NOTE: Removal is acceptable if shim is not OE. 

Shim worn 

A 

Require removal or replacement. See note 

below. 

NOTE: Removal is acceptable if shim is not OE. 

Slider pin (bolt) bent 

B 

Require replacement of slider pin or bolt and 

lubricants. 

Slider pin (bolt) rust-pitted 

A 

Require replacement of slider pin or bolt and 

lubricants. 

Slider pin (bolt) worn 

A 

Require replacement of slider pin or bolt and 

lubricants. 

Threads damaged 

A 

Require repair or replacement. 

Threads stripped (threads 
missing) 

A 

Require replacement. 

Worn, affecting performance 

A 

Require replacement. 

CAUTION: When installing loaded calipers, it is required that friction material be 

matched in axle sets for consistent braking characteristics. 

Condition 

Code 

Procedure 

Bleeder port damaged 

A 

Require repair or replacement of caliper. 

Bleeder screw broken off in caliper 

A 

Require repair or replacement of caliper. 

See note below. 

NOTE: Only required if the hydraulic system must be opened. 

Bleeder screw plugged 

A 

Require repair or replacement of bleeder 

screw. See note below. 

NOTE: Only required if the hydraulic system must be opened. 

Bleeder screw seized 

A 

Require replacement of caliper. See note 

below. 

NOTE: Seized is defined as a bleeder screw that cannot be removed after a practical 
attempt at removing. Only required if the hydraulic system must be opened. 

 

1998 Chevrolet Pickup C1500 

Uniform Inspection and Communication Standards BRAKE SYSTEMS

  

CONTROLLERS 

See Electronic Controllers.  

DIGITAL RATIO AXLE CONTROLLERS AND BUFFERS (DRAC AND DRAB) 

Digital Ratio Axle Controllers and Buffers (DRAC and DRAB) 

Casting corroded, affecting structural 
integrity 

A 

Require replacement. 

Casting damaged, affecting structural 
integrity 

A 

Require replacement. 

Dust boot around caliper torn 

A 

Require replacement of dust boot. 

Leaking 

A 

Require repair or replacement. 

Mounting pin threads damaged 

A 

Require repair or replacement of 

component with damaged threads. 

Mounting pin threads stripped in caliper 
bracket (threads missing) 

A 

Require repair or replacement of caliper 

bracket. 

Mounting pin threads stripped in 
steering knuckle (threads missing) 

A 

Require repair or replacement of steering 

knuckle. 

Mounting pin threads stripped (threads 
missing) 

A 

Require repair or replacement of 

component with stripped threads. 

Parking brake cable support, lever, or 
return spring bent 

A 

Require replacement of parts. 

Parking brake cable support, lever, or 
return spring broken 

A 

Require replacement of parts. 

Parking brake mechanism in caliper 
inoperative 

A 

Require repair or replacement. 

Piston corroded (pitted or peeling 
chrome plating) 

B 

Require replacement of piston and 

rebuilding or replacement of caliper. 

Piston damaged, affecting performance 

B 

Require replacement of piston and 

rebuilding or replacement of caliper. 

Piston damaged, not affecting 
performance 

No service suggested or required. 

Piston finish worn off 

B 

Require replacement of piston and 

rebuilding or replacement of caliper. 

Piston sticking 

A 

Require rebuilding or replacement of 

caliper. 

Slide mechanism sticking 

A 

Require repair or replacement of slide 

mechanism. 

Condition 

Code 

Procedure 

Connector broken 

A 

Require repair or replacement. 

 

1998 Chevrolet Pickup C1500 

Uniform Inspection and Communication Standards BRAKE SYSTEMS

  

DISABLE SWITCHES 

See Switches.  

DRUMS 

Determine the need to recondition based upon individual drum conditions that follow. Friction material 
replacement does not require drum reconditioning unless other justifications exist. Do not recondition new 
drums unless they are being pressed or bolted onto an existing hub. It is not necessary to replace drums in axle 
sets. However, when replacing or reconditioning a drum due to the conditions that follow, you may suggest 
reconditioning of the other drum on the same axle to eliminate uneven braking behavior. Always wash drums 
after servicing or before installing.  

Drums 

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. 

Missing 

C 

Require replacement. 

Output signal incorrect 

B 

Require repair or 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. 

Condition 

Code 

Procedure 

Balance weight missing 

No service suggested 

or required. 

Bell-mouthed, affecting performance 

A 

Require 

reconditioning or 

replacement. 

Cooling fin broken 

No service suggested 

or required. 

Cracked 

B 

Require replacement. 

 

1998 Chevrolet Pickup C1500 

Uniform Inspection and Communication Standards BRAKE SYSTEMS

  

ELECTRICAL PUMPS AND MOTORS 

Copied fuel pump conditions from engine UIGs & deleted pulsator from leaking conditions.  

Electrical Pumps and Motors 

Drum diameter is greater than OEM "machine to" 
specifications but less than "discard at" specifications, and 
the drum does not require reconditioning 

1 

Suggest replacement. 

See note below. 

NOTE: Only applies to vehicles for which OEM "machine to" specifications exist. If 
OEM does not supply "machine to" specifications, the drum may be worn to discard 
specifications. 

Drum diameter will exceed OEM "machine to" 
specifications after required reconditioning 

B 

Require replacement. 

See note below. 

NOTE: If OEM does not supply "machine to" specifications, you may machine to 
discard specifications. 

Hard-spotted 

2 

Suggest 

reconditioning or 

replacement. 

Measured diameter is greater than OEM discard 
specifications 

B 

Require replacement. 

Out-of-round (runout), affecting performance 

A 

Require 

reconditioning or 

replacement. 

Out-of-round (runout), exceeding manufacturer's 
specifications 

B 

Require 

reconditioning or 

replacement. 

Scored 

B 

Require 

reconditioning or 

replacement. 

Surface threaded due to improper machining 

B 

Require 

reconditioning or 

replacement. 

Tapered, affecting performance 

A 

Require 

reconditioning 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. 

Connector broken 

A 

Require repair or replacement. 

 

1998 Chevrolet Pickup C1500 

Uniform Inspection and Communication Standards BRAKE SYSTEMS