1997 Chevy Suburban brake pull

In theory, rear brake issues can cause a pull as well, although I am not supporting their decision 100%. I did some research and found two service bulletins regarding brake pull on 'heavy' Suburbans. They should have had access to these as I got them from GM service information. I think one bulletin is a revision of the other, but both state on Suburban models a combination(or proportioning) valve should be installed. These also apply only if your vehicle has the corresponding options.
#99-05-24-001A: Tech - Brake Lead/Pull and Frt Brake Wear (Repl. Frt Brake Pads, Rr Brake Shoes) - (Sep 2, 1999)

Subject: Brake Lead/Pull and Front Brake Wear (Replace Front Brake Pads And/Or Rear Brake Shoes)

Models: 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, DURASTOPà † 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.

#86-50-20A: BRAKE LEAD/FRT BRAKE WEAR (REPLACE REAR BRAKE SHOES) - (Sep 18, 1998)

REVISION: 09/17/98 DIVS INVL 1 5 7

THIS BULLETIN IS BEING REVISED TO CHANGE A LABOR OPERATION NUMBER AND ADD INFORMATION TO THE MODELS AND CORRECTION SECTIONS. PLEASE DISCARD CORPORATE BULLETIN NUMBER 86-50-20 (SECTION 5 - BRAKES). ______________________________________________________________________

SUBJECT: BRAKE LEAD/PULL AND FRONT BRAKE WEAR (REPLACE REAR BRAKE SHOES)

MODELS: 1992-98 CHEVROLET AND GMC C/K MODELS WITH RPO JB8 1992-98 CHEVROLET AND GMC C/K SUBURBAN MODELS WITH RPO JD7 AND 6.5L OR 7.4L ENGINE 1996-98 CHEVROLET AND GMC G VANS WITH RPO JB8

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:

CONDITIONS MAY BE CAUSED BY EXCESSIVE WEARING OF THE FRONT BRAKE MATERIAL. IMPROVEMENTS TO THE ABOVE CONDITIONS CAN BE GAINED THROUGH REAR BRAKE MATERIAL MODIFICATIONS. ON THE SUBURBAN MODELS, THE BEST PERFORMANCE FROM THIS NEW BRAKE MATERIAL CAN BE ACHIEVED WITH REPLACING THE PROPORTIONING VALVE.

CORRECTION:

REPLACE THE REAR BRAKE SHOES WITH DURA STOP(TM) BRAKE SHOE KIT. ON SUBURBAN MODELS, A PROPORTIONING VALVE MUST BE INSTALLED. **ALL OTHER MODELS (C/K, G), NO PROPORTIONING VALVE CHANGE IS REQUIRED.** USE THE PART NUMBERS LISTED BELOW. REFER TO SECTION 5C2 OF THE APPROPRIATE SERVICE MANUAL.

IMPORTANT: IF YOU ENCOUNTER DISC BRAKES THAT ARE EXCESSIVELY 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. REFER TO SERVICE MANUAL SECTION 5-111 FOR ADDITIONAL INFORMATION ON THIS PROCEDURE. **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 0.20 MM (0.008 IN.), YOU MUST CORRECT THIS BY FILING METAL OFF AT THE STEERING KNUCKLE STOPS IN ORDER TO OBTAIN A TOTAL CLEARANCE OF 0.25 TO 0.61 MM (0.010 TO 0.024 IN.). **DO NOT FILE METAL OFF OF THE CALIPER.**

That is a bit of a shocker that they are willing to absorb it if the repair is unsuccessful. It at least shows they have some confidence that it will fix it. As far as the mushy pedal, does it change with several pumps of the pedal? It looks like they had the hydraulic system open, and perhaps there is still some air in it.