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Double Belt Alternator Pulley – Fits Volvo Penta AD31, AD41, AQAD30/40 Series (Replaces 841812)

Regular price $39.90
Shipping calculated at checkout.

Double Belt Alternator Pulley – Fits Volvo Penta AD31, AD41, AQAD30/40 Series (Replaces 841812) is backordered and will ship as soon as it is back in stock.


Worry-free returns

You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).

You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).

If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.

Delivery and Shipping

Free standard shipping on all orders under 1 KG

If you have any questions, feel free to email us at info@sierramarines.com, and we’ll get back to you within 20–36 hours.

Product Details

This aftermarket Double Belt Alternator Pulley is designed for a broad range of Volvo Penta inboard diesel engines, including the AD31, TAMD31, TMD31, AQAD31, AD41, TAMD41, TMD41, and AQAD41 series manufactured in the 1980s and 1990s. It ensures reliable power transmission from the engine to the alternator.

It serves as a direct replacement for Volvo Penta part number 841812, offering a precise fit and restoring original performance.

  • Engineered for direct bolt-on installation.
  • Designed for a double V-belt configuration.
  • Includes a 1-year warranty against manufacturing defects.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Brand Part Number
Volvo Penta 841812

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This part is compatible with the following Volvo Penta engine models.

Brand Model Stroke Years OEM Part No.
Volvo Penta AD31A, AD31B 4-Stroke 1980s–1990s 841812
Volvo Penta AD31D, AD31L 4-Stroke 1980s–1990s 841812
Volvo Penta AD31P, AD31XD 4-Stroke 1980s–1990s 841812
Volvo Penta AQAD30A 4-Stroke 1980s–1990s 841812
Volvo Penta AQAD31A 4-Stroke 1980s–1990s 841812
Volvo Penta KAD32P 4-Stroke 1980s–1990s 841812
Volvo Penta TMD31A, TMD31B 4-Stroke 1980s–1990s 841812
Volvo Penta TMD31D, TMD31L-A 4-Stroke 1980s–1990s 841812
Volvo Penta TAMD31A, TAMD31B 4-Stroke 1980s–1990s 841812
Volvo Penta TAMD31D, TAMD31P, TAMD31L, TAMD31S 4-Stroke 1980s–1990s 841812
Volvo Penta AD41A, AD41B 4-Stroke 1980s–1990s 841812
Volvo Penta AD41D 4-Stroke 1980s–1990s 841812
Volvo Penta AD41L, AD41P 4-Stroke 1980s–1990s 841812
Volvo Penta AQAD40A, AQAD40B 4-Stroke 1980s–1990s 841812
Volvo Penta AQAD41A 4-Stroke 1980s–1990s 841812
Volvo Penta TAMD41A, TAMD41B 4-Stroke 1980s–1990s 841812
Volvo Penta TAMD41D 4-Stroke 1980s–1990s 841812
Volvo Penta TAMD41H, TAMD41L, TAMD41M, TAMD41P 4-Stroke 1980s–1990s 841812
Volvo Penta TMD41A, TMD41B 4-Stroke 1980s–1990s 841812
Volvo Penta TMD41D, TMD41L 4-Stroke 1980s–1990s 841812

Technical Specs

Product Type
Double Belt Alternator Pulley
Installation
Direct bolt-on replacement
Connection
Direct mount to alternator shaft
Fitting Type
Double V-belt
Warranty
1-year warranty against manufacturing defects

What’s in the Box

  • 1 x Double Belt Alternator Pulley (Replaces 841812)

Installation Notes

  1. Disconnect the negative battery terminal to prevent electrical hazards.
  2. Loosen the alternator tensioner and remove the drive belt from the pulley.
  3. Use an impact wrench or appropriate pulley holding tool to remove the central retaining nut and slide the old pulley off the alternator shaft.
  4. Clean the alternator shaft and keyway, ensuring they are free of dirt and corrosion.
  5. Slide the new pulley onto the shaft, aligning it with the keyway.
  6. Reinstall and tighten the retaining nut to the manufacturer's recommended torque specification.
  7. Reinstall the drive belt and set the correct tension.
  8. Reconnect the battery terminal and start the engine to verify proper operation.

Troubleshooting & FAQ

How can I confirm this pulley fits my specific engine?

The most reliable method is to match the OEM part number 841812 from your existing pulley or service manual. You can also use our compatibility table to check if your engine model and year range are listed.

What are common signs of a failing alternator pulley?

Symptoms include a squealing or grinding noise from the engine bay, visible wobble or runout on the pulley, premature belt wear, and inconsistent charging system performance (flickering lights, battery issues).

Is a special tool required for installation?

You may need an impact wrench or a specialized alternator pulley removal tool to loosen the central nut, as it is often very tight. The specific tool depends on your alternator model.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

Shipping speed & cost?

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

Warranty & returns?

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.

Safety & Important Info

  • Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
  • This is an aftermarket replacement, not an OEM component.
  • Professional installation is recommended for safety and performance.

About Sea Sierra

  • Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
  • Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
  • Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.

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