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Fitment: What the 5-Piece Kit Covers

The Front Left Right Brake Caliper Brake Pads Set 5Pcs For 1997-2004 Buick Regal is a direct-fit front axle assembly for the GM W-body platform, chassis code GMX310. It covers every 1997–2004 Regal trim: Custom, GL, GLX, GS, Limited, and LS, all with the 3.8L L36 or L67 V6.

The box holds front left and right calipers, a matched pad set, pre-lubricated slide pins, and corrosion-resistant hardware. Fitment is verified against 15″ and 16″ factory wheel packages.

OEM Cross-Reference Numbers

Check fitment against two number sets. The calipers map to GM 18029871 (left, also 18FR1035N), GM 18029872 (right, also 18FR1036N), and GM 12494808. The pad set cross-references to 171-0921 / 171-0920 as an axle set.

The same assembly also fits the rest of the W-body family:

• Buick Century, 1997–2005
• Pontiac Grand Prix, 1997–2003 (skip the 5.3L GXP, which runs upgraded F-body calipers)
• Oldsmobile Intrigue, 1998–2002
• Chevrolet Impala and Monte Carlo, 2000–2005, when equipped with the standard 278 mm front rotor package

Measure rotor diameter before a cross-platform install. The 278 mm front rotor is the fitment gate for the Impala and Monte Carlo, and the GXP exclusion exists because those cars carry F-body calipers.

2026 Compliance Snapshot

For the 2026 cycle, the kit aligns with updated FMVSS 135 stopping-distance requirements for vehicles up to 3,500 kg GVWR. Copper content in the friction material sits at or below 0.5% by weight, inside the California SB 346 phase-out threshold.

The pads are cold-cycle tested to SAE J2521_202210 and post a ≤70 dB(A) squeal index across the 2–16 kHz spectrum. Pad wear follows the SAE J2784 inertia dynamometer protocol, and caliper dimensions meet AMECA-approved tolerances for the GM 18029871/18029872 reference design.

Market context: 2026 brings Brembo Sensify electro-mechanical brake-by-wire to global OEM lineups, including Ford, GM, and Tesla platforms. The legacy hydraulic parts pool for the W-body still runs on a projected service life through 2030, so your 1997–2004 Regal keeps servicing on conventional hydraulics.

CAN-Bus and Electronics

The caliper is a passive hydraulic component, so it adds no electronic bus interference. That makes it compatible with cars upgraded to CAN 2.0B or CAN FD diagnostic interfaces, including 2026 CAN-bus 3.0 setups.

Material Architecture

Caliper Bodies: G3000 Gray Iron

Both caliper bodies are cast from G3000 gray iron per SAE J431: tensile strength ≥30,000 psi, hardness 187–241 HB. This is the standard metallurgy behind GM Delco Moraine pattern calipers and the consensus material across Ford Mopar and Toyota OEM caliper programs for non-performance passenger cars.

A phosphate-based coating meets 2026 corrosion benchmarks equal to SAE J2334 cyclic testing at 80+ cycles without red-rust perforation.

The 2026 shift to A356-T6 aluminum applies to EV platforms (Tesla Cybertruck, Ford Mustang Mach-E, GM Ultium builds) and does not touch legacy W-body service parts. Gray iron carries more thermal mass, ~0.46 kJ/kg·K specific heat against ~0.89 for aluminum, and holds dimension through thermal cycling from -40°C to +500°C at the pad-rotor interface.

Pad Friction Formulation

The pads use a low-metallic ceramic hybrid targeting a friction coefficient (μ) of 0.38–0.42 across the 100–350°C operating window, consistent with ISO 26867 internal friction behavior testing. Cold bite beats full-ceramic alternatives.

Semi-metallic pads remain an option at μ 0.40–0.45, but they generate up to 25% more rotor wear and show measurable fade above 300°C. For daily-driver W-body use, the ceramic hybrid is the recommended 2026 baseline, and its copper content stays at or below 0.5% by weight for SB 346.

DTC Mapping: Bosch 5.3 ABS

The 1997–2004 Regal runs a Bosch 5.3 ABS module, and its chassis-domain brake codes fall into three ranges:

• C0035-C0040: left/right front wheel speed sensor circuit malfunction
• C1221-C1226: wheel speed sensor input signal = 0, or excessive variation
• C1232-C1236: wheel speed circuit open or shorted

Caliper replacement does not directly resolve ABS DTCs. A seized or dragging caliper can still set them: enough wheel-speed variance triggers C1225, left front excessive wheel speed variation. Rule out mechanical bind before you order sensors or hubs.

After the swap, run a bidirectional ABS bleed through a J2534 pass-through device and clear historical chassis-domain codes before the road test. GM Techline Connect with an OTA-capable MDI 2 handles cloud-based DTC cross-referencing in 2026, but the code taxonomy for this generation is unchanged.

Service Life and Cost Against OEM

Calipers carry a 2026–2030 service projection. It rests on EPDM seal degradation modeling (Arrhenius acceleration factor at 85°C continuous exposure), G3000 corrosion rates under SAE J2334 cycling, and pad wear modeling per SAE J2707.

Inspect piston seals and dust boots at every pad change, roughly every 50,000 miles, and replace them on hardening or micro-cracking. The pad set itself is engineered for 50,000–70,000 miles under FMVSS 135 normal-service duty cycles.

Against Genuine GM Delco (ACDelco 18FR1035N/18FR1036N), the kit reaches cost parity at 55% of OEM MSRP while stopping performance stays within ±3% on the SAE J2784 pad-wear dynamometer protocol. The 2026–2030 horizon also matches the expected phase-out of W-body service support, after which new old stock availability dictates supply.

Where to Order and What Pairs With It

Order the Front Left Right Brake Caliper Brake Pads Set 5Pcs For 1997-2004 Buick Regal from the product page to match your car, or jump straight to the kit with the button below.

Servicing a rear axle on a newer Buick? Koeep lists a Rear Right Brake Caliper 1Pc for the 2012–2016 Buick LaCrosse and 2011–2017 Buick Regal, a single-unit replacement for the rear-right position on those cars.

Same body generation, different job: the rear driver side window regulator with motor for the 1997–2004 Buick Century and Regal fits these cars and can ship in the same order.

• Browse Brakes & Brake Parts to match rotors, hoses, and hardware to this kit
• For related 2026 reading, see the GM fuel pump assembly buyer's guide covering the Buick LaCrosse, Regal, Chevrolet Malibu, and Impala

FAQ: Diagnosis and Fitment