For those interested, I did some Googling and found the relevant GM TSB that was mentioned here. It's TSB #99-05-24-001. Apparently "Combination Valve" is the proper GM terminology for part number 12548265, and it's only necessary to swap to it if you have a Suburban. There's also a different part number for '92-'94 Suburbans.
TSB 99-05-24-001
Caliper TSB
Tech - Brake Lead/Pull and Frt Brake Wear (Repl. Frt
Brake Pads, Rr Brake Shoes) #99-05-24-001A
Brake Lead/Pull and Front Brake Wear (Replace Front Brake Pads And/Or Rear
Brake Shoes)
1992-1999 Chevrolet and GMC C/K Cab Chassis, Crew Cab, and Pickup Models
with Power Brakes (RPO JB8)
1992-99 Chevrolet and GMC C/K Suburban Models with 8600# GVW (RPO C6P)
1996-2000 Chevrolet and GMC G Vans with Power Brakes (RPO JD7 & JB8) and
GVW's of 7,700# up to 9,500# (RPO's
C3F, C6P, & E23)
This bulletin is being revised to update information in the Models Section
and Correction Information. Please discard Corporate
Bulletin Number 99-05-24-001 (Section 5 -- Brakes).
Condition
Some owners may comment about the vehicle leading or pulling to either side
while applying the brakes, and premature front
brake wear, especially vehicles that have been used to tow a heavy load.
Cause
The condition may be caused by wearing of the front brake material.
Improvements to the above conditions can be gained
through brake material modifications. On the Suburban models, the best
performance from this new brake material can be
achieved with replacing the brake combination valve.
Correction
Replace the rear brake shoes with P/N 18029651. THIS FIX DOES NOT APPLY TO
THE 13 x 2 1/2 BRAKE,
DURASTOPT P/N 18029650, OR ANY OTHER SIZE. On Suburban models, a brake
combination valve must be
replaced. ALL OTHER MODELS (C/K, G Van), NO BRAKE COMBINATION VALVE CHANGE
IS REQUIRED.
Refer to the Drum Brakes or Hydraulic Brakes subsection of the appropriate
Service Manual. For G2/G3 Series Vans only
(with GVW's of 7,700# up to 9,500# -- RPOs C3F, C6P, E23) also replace the
front brakes pads with P/N 12471685.
Refer to the Disc Brake subsection of the appropriate Service Manual.
Important
The new front brake pad material has been selected for improved wear
characteristics. Some customers may experience
increased brake noise from this brake pad and should be advised that some
squeal is a characteristic of this particular material.
Important
If you encounter disc brakes that are extremely worn on the inboard side,
with very little wear to the outboard side, verify the
clearance between the caliper and the steering knuckle bracket stops.
MEASURE THE CLEARANCES INDIVIDUALLY AND ADD THE CLEARANCES TOGETHER FOR
TOTAL
CLEARANCE BEFORE REMOVING THE CALIPER. If the caliper (total clearance) to
the steering knuckle stops is under
0.26 mm (0.010 in), correct this by filing metal off at the steering knuckle
stops in order to obtain a total clearance of
0.26 to 0.60 mm (0.010 to 0.024 in). DO NOT FILE METAL OFF OF THE CALIPER.
Refer to the Disc Brake subsection
of the appropriate Service Manual for additional information on this
procedure.
Parts Information
Part Number
Description
Qty
18029651 (17452R Canada)
Shoe Kit, RR Drum Brk (13 x 3.5 in.)
1
12471685
Pad Kit, Frt Disc Brk
1
15650150 (92-94 Suburbans)
Valve Asm., Brake Comb.
1
12548265 (95 and Newer Suburbans)
Valve Kit, Brake Comb.
1
Parts are currently available from GMSPO.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation
Description
Labor Time
H0257
Shoes and Linings, Drum Brake - R&R or Replace (Rear)
Use published labor operation time
H0042
Pads, Disc Brake - R&R or Replace (Front)
1.0 hr*
H0780
Valve, Brake Combination - Replace
Use published labor operation time
*This time is updated from the current Labor Time Guide. The next issue will
contain this change
