Genuine Mazda Alternator Adjuster Spacer Block Bolt – M8 x 35mm • 9079-40-835

Genuine Mazda Alternator Adjuster Spacer Block Bolt – M8 x 35mm

Replacement Genuine Mazda alternator adjuster spacer-block fixing bolt for Mazda MX-5 Mk1 NA 1.8 and all Mk2/Mk2.5 NB 1.6 and 1.8 models.

This flange bolt secures the alternator adjustment spacer block to the alternator mounting bracket. The spacer block forms part of the mechanical adjustment system used to move the alternator and set the correct alternator and water-pump drive-belt tension.

The bolt must hold the spacer block securely while allowing the adjustment mechanism to operate correctly. A seized, stretched or damaged bolt can make drive-belt adjustment difficult and may prevent the alternator from remaining securely positioned.

One bolt is fitted per vehicle, and this listing supplies one Genuine Mazda bolt. The spacer block, long adjustment bolt and other alternator mounting hardware are supplied separately.

Important fitment restriction: This bolt fits the Mk1 NA 1.8 and Mk2/Mk2.5 NB alternator adjuster arrangement. The Mk1 NA 1.6 uses a different fixing bolt, spacer block and adjustment bolt.

• Part type: Alternator adjuster spacer-block fixing bolt
• Common names: Alternator tensioner block bolt / adjuster bracket bolt / locking bolt
• Mazda catalogue description: Bolt and washer, flange
• Location: Alternator adjustment spacer block to alternator bracket
• Function: Secures the alternator belt-adjustment spacer block
• Thread size: M8
• Nominal length: 35mm
• Thread pitch: 1.25mm
• Design: Flange-head bolt
• Quantity fitted per vehicle: 1
• Quantity supplied: 1 bolt
• Spacer block included: No
• Long adjustment bolt included: No
• Alternator included: No
• Drive belt included: No
• Brand: Genuine Mazda
• Part No.: 9079-40-835

Typical reasons for replacement:

• Bolt seized through corrosion
• Threads damaged or cross-threaded
• Bolt head rounded during removal
• Bolt stretched or bent
• Original fastener missing
• Spacer block or alternator bracket replacement
• Alternator removal or refurbishment
• Drive-belt tension cannot be retained correctly

Fitment advice: Confirm that the vehicle uses the Mk1 1.8 or Mk2/Mk2.5 alternator adjuster arrangement. Do not order this bolt for a Mk1 1.6 without confirming that the alternator mounting system has been changed.

Replacement advice: Inspect the spacer block, alternator bracket, long adjustment bolt, lower alternator pivot bolt and all associated threads before installation. A replacement bolt will not correct a cracked bracket or damaged threaded component.

Other items to consider: Inspect the alternator and water-pump drive belt for cracking, glazing or contamination. Check the alternator bearings, water-pump pulley, crankshaft pulley and surrounding mounting hardware.

Useful tools / consumables: Socket and spanner set, calibrated torque wrench, penetrating fluid, wire brush, thread-cleaning tools and suitable belt-tension measuring equipment.

Difficulty guide: DIY Difficulty: Easy to Moderate. The fastener is relatively accessible, although corrosion and damaged threads can make removal more difficult.

Why Genuine Mazda? Genuine Mazda alternator hardware matches the original thread pitch, bolt length, flange dimensions and strength specification. Correct hardware helps the spacer block remain securely positioned while the drive belt is adjusted.

What’s in the box: One Genuine Mazda alternator adjuster spacer-block flange bolt, part number 9079-40-835.

Installation notes: Disconnect the battery before working around the alternator. Support the alternator and loosen the appropriate pivot and adjustment hardware. Remove the original spacer-block bolt and inspect the bracket and threaded mounting point. Start the replacement bolt by hand to prevent cross-threading. Reassemble the adjustment mechanism, set the drive belt to the specified tension and tighten all alternator mounting hardware to the applicable Mazda specification. Recheck belt alignment and tension after installation.