Genuine Mazda Power Plant Frame PPF Mounting Bolt • NA01-39-721A

Genuine Mazda Power Plant Frame PPF Mounting Bolt

Replacement Genuine Mazda Power Plant Frame mounting bolt for Mazda MX-5 Mk1 NA and Mk2/Mk2.5 NB models.

The Power Plant Frame, commonly abbreviated to PPF, is the rigid aluminium structure connecting the gearbox to the rear differential. It helps maintain the intended alignment between the engine, gearbox and differential while supporting the rear-wheel-drive powertrain assembly.

This bolt forms part of the principal PPF mounting arrangement. Correct fasteners and clamping loads are important because movement or incorrect alignment within the PPF assembly can contribute to drivetrain vibration, gear-selection problems, mounting stress or accelerated wear.

Mazda specifies three NA01-39-721A bolts within the PPF mounting arrangement per vehicle. This listing supplies one Genuine Mazda bolt, so order a quantity of three when renewing the complete set.

Important distinction: This is the principal PPF mounting bolt listed as diagram reference 39721. The separate stepped PPF-to-differential bolt, NA01-39-722, and its top-hat spacer, NA01-39-723, are different components and are not included.

• Part type: Power Plant Frame mounting bolt
• Common names: PPF bolt / transmission-support bolt / powertrain-frame bolt
• Mazda catalogue description: Bolt, Plant Frame
• Location: Power Plant Frame mounting assembly
• Function: Secures the PPF within the gearbox and differential mounting structure
• Mazda diagram reference: 39721
• Quantity fitted per vehicle: 3
• Quantity supplied: 1 bolt
• Plain washer included: No
• Stepped PPF bolt included: No
• Top-hat spacer included: No
• Power Plant Frame included: No
• Brand: Genuine Mazda
• Part No.: NA01-39-721A
• Previous Mazda reference: NA01-39-721
• MX-5 fitment: All Mk1 NA and Mk2/Mk2.5 NB models

Typical reasons for replacement:

• Bolt seized through corrosion
• Threads damaged or cross-threaded
• Bolt head rounded during removal
• Bolt bent, stretched or fractured
• Original fastener missing
• Power Plant Frame removal or replacement
• Gearbox or differential removal
• Drivetrain alignment work
• Previously fitted incorrect or non-standard hardware

Quantity advice: Three of these mounting bolts are specified within the PPF assembly. This listing supplies one bolt per order quantity.

Fitment advice: NA01-39-721A is used across the Mk1 NA and Mk2/Mk2.5 NB Power Plant Frame arrangement. Confirm that the required component is the principal PPF mounting bolt rather than the separate stepped bolt or shorter lower-bracket fastener.

Replacement advice: Inspect all three mounting bolts, their corresponding washers, threaded mounting points and PPF apertures. A new bolt will not correct damaged threads, distorted mounting faces, elongated apertures or a cracked Power Plant Frame.

Alignment advice: The Power Plant Frame controls the relative position of the gearbox and differential. Its specified alignment should be restored before the mounting bolts are finally tightened. Incorrect alignment can introduce drivetrain vibration and place unnecessary load on the gearbox and differential mountings.

Other items to consider: Inspect the three NA01-39-724 plain washers, the NA01-39-722 stepped PPF bolt, NA01-39-723 top-hat spacer, lower PPF bracket hardware, gearbox mounting and differential mounting components.

Useful tools / consumables: Socket and spanner set, calibrated torque wrench, penetrating fluid, wire brush, thread-cleaning tools, suitable gearbox and differential support equipment and measuring tools for PPF alignment.

Difficulty guide: DIY Difficulty: Moderate. Bolt replacement requires the drivetrain and Power Plant Frame to be safely supported. Correct PPF alignment must be established before final tightening.

Why Genuine Mazda? Genuine Mazda PPF hardware matches the original thread specification, shank dimensions, head profile and strength requirements. Correct mounting hardware is important for maintaining the intended gearbox-to-differential alignment and clamping load.

What’s in the box: One Genuine Mazda Power Plant Frame mounting bolt, part number NA01-39-721A.

Installation notes: Safely support the gearbox, differential and Power Plant Frame before loosening the mounting hardware. Remove the original bolt and inspect its threads, corresponding washer, mounting aperture and threaded location. Start the replacement bolt by hand to prevent cross-threading. Reassemble the PPF mounting components without fully tightening them, establish the specified gearbox-to-differential alignment, and then tighten the hardware using the applicable Mazda procedure.