A33‑1268 vs A33‑1268BP: Wherethe Narrow T680 FairingBracket Breaks

Summary. The OEM Kenworth A33-1268 is an injection molded, 40% glass filled polypropylene bracket whose narrow end is formed as an open window bounded by thin walls. That end is the location of the in-service failure documented below. The A33-1268BP, a replacement for Kenworth part number A33-1268, closes that section with a solid bridge, adds reinforcement along the load path, and is manufactured from carbon fiber reinforced plastic. It installs on the factory mounting points without modification and is priced at $30.00, compared with $66.12 to $137.33 for the OEM part at the retailers surveyed. Where warranty terms, fleet policy or same day availability require a genuine Kenworth part, the OEM bracket remains the appropriate choice.

Bushido Performance manufactures the A33-1268BP. The findings on this page are drawn from an OEM part in our possession, field documentation of a failed bracket, customer reports and a bench comparison, and inference is identified as such throughout. Bushido Performance is not affiliated with Kenworth or PACCAR.

Readers still diagnosing a lower fairing that sits out of level should begin with our diagnostic guide to T680 fairing bracket failure. This page addresses the next decision: which replacement bracket to specify.

Comparison at a glance

Documented failure point on the OEM bracket

On 28 August 2026, Bushido Performance recorded video beneath the step of a parked Kenworth T680 Next Gen whose lower fairing panel had separated from the body. The panel showed no evidence of impact. The footage was then reviewed frame by frame to examine the brackets in place.

For reference, a new OEM A33-1268 terminates in a closed loop: a rectangular window bounded by a thin wall on each side and across the end. On the vehicle recorded, that end is open.

Note on the image below. Figure 1 is a single frame from handheld video recorded beneath the vehicle. Detail is limited: the bracket is dark material in shadow against a brightly lit gap, and the finding is the absence of material rather than a visible fracture. It is best read alongside Figure 2, which shows the same end of an intact part.

This finding is consistent with reports from fleet customers, which describe cracking near the screw at the mounting end and increased flexing of the bracket as it degrades. These reports are anecdotal rather than the product of a formal failure study, and they are not sufficient to establish a failure rate. They do, however, point to the same regions of the part, and those regions share a common geometry.

Why the narrow end is vulnerable

At its narrow end, the OEM bracket transmits load through two thin walls with no material between them. A crack initiating in that section has little material to propagate through, and the internal corners of the window concentrate stress where the cross section is smallest. The design is efficient for a lightweight molded part, but it places the least material at a location subject to repeated loading from a wind loaded panel at highway speed. This assessment is based on the geometry of the part rather than on fracture analysis. Creep, notch sensitivity and the full failure sequence are covered in the diagnostic guide.

Design changes in the A33-1268BP

Each change addresses a specific weakness identified above.

• Solid bridge across the open section. The open window of the OEM design is closed, eliminating the thin walled frame at the location of the documented failure.
• Reinforced clip seats. Additional material behind each seat, where wear typically begins.
• Increased wall thickness. Greater cross section at load bearing locations, increasing the material a crack must traverse.
• Internal rib structure. Distributes load along the length of the part rather than concentrating it at corners and at the fastener.
• Carbon fiber reinforced plastic. Selected for dimensional stability under sustained load and for thermal margin behind the panel, with a published heat deflection temperature of 194 °C against approximately 150 °C for the OEM material class.

Bench torsion comparison

Bushido Performance conducted a bench comparison in which an OEM A33-1268 and an A33-1268BP were each clamped and subjected to torsion. The A33-1268BP sustained greater deflection and returned to shape without visible damage. The OEM part exhibited cracking under comparable loading. This was a single, uninstrumented comparison of one sample of each part and should not be read as quantitative test data. The result is consistent with the design intent of the A33-1268BP, which is to accommodate panel movement rather than resist it rigidly.

When the OEM A33-1268 is the appropriate choice

• The vehicle is under factory warranty and the repair is being performed by a dealer.
• Fleet or lease requirements specify genuine parts.
• Same day availability is required and a local dealer has the part in stock.

The A33-1268BP is an aftermarket part. Only a part supplied through Kenworth is OEM, and a listing that describes a non-dealer bracket as genuine is inaccurate.

Pricing and availability

OEM prices reflect online listings on 15 September 2026, excluding shipping. Pricing varies by retailer and over time and should be confirmed at the point of purchase.

Methodology and disclosure

Bushido Performance manufactures the A33-1268BP and therefore has a commercial interest in this comparison. The evidence consists of a new OEM A33-1268 in our possession, marked >PP-GF40< REV C; video of a parked T680 Next Gen recorded on 28 August 2026, from which Figure 1 is drawn; photographs of the OEM part and the A33-1268BP together, shown in Figures 3 and 4; reports from fleet customers, who are not identified; and a single bench torsion comparison of one sample of each part. All photographs were taken by Bushido Performance. In Figures 3 and 4 the background surface has been replaced with white; the parts themselves, including all openings, are unaltered. No other image has been edited. Neither part has undergone laboratory testing.

Sources

• OEM material. Taken from the molded marking on the A33-1268 shown in Figure 2.
• Heat deflection temperature. ISO 75. The A33-1268BP figure is the published technical data sheet value for the material grade used: 194 °C at 0.45 MPa and 170 °C at 1.8 MPa. The OEM figure is a representative published value for glass filled polypropylene and not the specification of any single product. See Figure 7 of the diagnostic guide.
• OEM pricing. Big Rig World, BuyParts.Online and FinditParts, whose price was observed on its eBay storefront, accessed 15 September 2026.

Frequently asked questions

Is the A33-1268BP better than the OEM A33-1268?

At the location where the OEM bracket has been documented to fail, the A33-1268BP adds a solid bridge across the open end section, together with thicker walls and internal ribs. In a bench torsion comparison it sustained greater deflection without damage, while the OEM part cracked. It is priced at $30.00 against $66.12 to $137.33 for the OEM part. The OEM part remains the appropriate choice where warranty or fleet requirements call for genuine Kenworth parts.

Does the A33-1268BP require drilling or modification?

No. The A33-1268BP replaces Kenworth part number A33-1268 on the T680 Next Gen, model year 2022 and later, using the factory mounting points and clips. Worn clips should be replaced at the same time.

What material is the OEM A33-1268 made from?

PP-GF40, a polypropylene with 40% glass fill, injection molded. The designation is molded into the part together with the revision level, REV C. It is a standard specification for a component in this position.

Should the A33-1266-100 brackets be replaced at the same time?

When one bracket has failed, the remaining brackets have carried additional load, and all three should be inspected. The set includes two A33-1266-100BP and one A33-1268BP for $85.00. Inspection steps are covered in the diagnostic guide.

What warranty is provided?

The A33-1268BP carries a 90 day warranty from delivery covering defects in materials and workmanship. The warranty does not cover damage resulting from improper installation, collision or misuse. Claims require proof of purchase and photographs of the defect.