Bosch Alternator 24V 120A 1986A01031

This Bosch alternator is a 24V, 120A heavy commercial unit with part number 1986A01031. It is listed as an alternator for heavy commercial use, with an internal regulator and an 8 groove pulley, so it suits applications that require those exact electrical and mounting details.

Mounting and pulley dimensions matter on alternators like this one. The unit has a twin leg alternator mount, 105mm inside mounting legs, 198mm mount centre to centre, a 13mm pivot hole diameter and an 11mm adjusting hole diameter. Those measurements should be checked against the existing unit before ordering, especially on vehicles where bracket and pulley alignment must match closely.

The alternator is described as excluding the vacuum pump, which is an important distinction when matching replacement units. It is manufactured in Spain, weighs 8.2kg, and comes with a 12 month warranty. For buyers comparing options, the key identifiers are Bosch, 24V, 120A, 1986A01031, internal regulator and twin leg mounting.

Key Features

• Bosch heavy commercial alternator
• 24V system voltage
• 120A charge current
• Internal regulator
• Twin leg alternator mount
• 8 groove pulley

Specifications

• Part No.: 1986A01031
• Voltage: 24V
• Charge current / power rating: 120A
• Alternator type: Excl. vacuum pump
• Pulley outside diameter: 73mm
• Pulley section: 8 groove
• Inside mounting legs: 105mm
• Mount centre to centre: 198mm

Fitment guidance

• Listed fitment support includes VOLVO FH II, VOLVO FM, VOLVO FM II and VOLVO FMX II applications
• Fitment samples shown include VOLVO FH II 2012, VOLVO FH II 2017, VOLVO FM 2012, VOLVO FM II 2013, VOLVO FM II 2015, VOLVO FM II 2017, VOLVO FMX II 2012 and VOLVO FMX II 2013
• Use the part number 1986A01031 and the mounting dimensions to confirm the correct replacement before ordering

Application and Buying Notes

When replacing an alternator, the safest check is the part number first. This Bosch unit is identified as 1986A01031 and is a 24V, 120A alternator with an internal regulator, so the electrical setup must match the vehicle’s charging system and the existing unit’s specification. If the old alternator has a vacuum pump, this unit is not the same type because it is listed as excl. vacuum pump.

Mounting measurements are just as important as the electrical rating. Confirm the 105mm inside mounting legs, 198mm mount centre to centre, 13mm pivot hole diameter, 11mm adjusting hole diameter and twin leg mount arrangement against the removed alternator or bracket set-up. A difference in any of these can stop the unit from fitting correctly, even if the Bosch part number looks similar.

The 8 groove pulley and 73mm pulley outside diameter should also be checked against the belt system already fitted to the vehicle. Bosch notes a recommended additional repair of the V-belt or V-ribbed belt, which is worth considering if the existing belt shows wear, glazing or cracking. Matching the pulley section and belt condition helps avoid unnecessary repeat work.

This alternator is listed for heavy commercial use and weighs 8.2kg, so careful handling during installation is sensible. The unit is made in Spain and carries a 12 month warranty. As with any charging system component, make sure the battery condition, belt tension and wiring are sound before condemning the alternator, because charging faults are not always caused by the alternator alone.

Before supply, the safest approach is to confirm the original unit details against the listed part number, voltage, output rating, mounting arrangement, and pulley configuration. That checking process is standard practice in the parts trade because visually similar units can still differ in service-critical ways.

For workshop, fleet, and equipment applications, accurate identification of part number 1986A01031 helps avoid unnecessary freight, additional labour, and vehicle or machine downtime. Where the application is not straightforward, the original unit, OEM reference, or workshop records should be used as the primary confirmation point.

Relevant published details for this unit include Type ALTERNATOR HEAVY COMM, Unit of Measure EACH, Warranty 12 Months, Inside Mounting Legs 105mm, Pivot Hole Diameter 13, Pulley Outside Diameter 73mm, Regulator Type Internal, Alternator Mount Twin Leg, Alternator Charge Current [A] 120, Alternator Type excl. vacuum pump.

Additional published details for cross-checking include Packaging length 28, Packaging height 22.5, Weight 8.2kg, Product Group 1 ROTATING ELECTRICAL, Part No. 1986A01031, Brand BOSCH, Description Bosch Alternator 24V 120A, Adjusting Hole Diameter 11, Pin Code IR98, Power Rating (Amp) 120.

Bosch Alternator 24V 120A. Part number 1986A01031 should be checked first. Listed voltage is 24. Listed output rating is 120. These details form the core reference points used by parts interpreters when confirming the correct replacement.

Mount style is Twin Leg. Regulator type is Internal. Pulley configuration is 8 Groove. Those physical and electrical details should line up with the original unit before the replacement is approved for fitment.

For part number 1986A01031, the normal identification sequence is part number, electrical rating, mounting arrangement, connector or terminal style, and pulley or drive details. Using those checkpoints helps confirm that the listed unit matches the service requirement rather than only looking similar.

Compatibility note: Confirm fitment by checking part number 1986A01031, 24V electrical specification, 120A output, internal regulator, twin leg mounting and the stated dimensions against the vehicle and removed unit before purchase.

FAQ

What is the part number for this Bosch alternator?

The part number listed is 1986A01031.

Is this alternator 12V or 24V?

It is a 24V alternator.

What output does it provide?

The alternator is listed at 120A charge current, also shown as 120A power rating.

Does it have an internal regulator?

Yes. The regulator type is listed as internal.

What vehicles is fitment shown for?

Fitment support is shown for VOLVO FH II, VOLVO FM, VOLVO FM II and VOLVO FMX II applications, with sample model years including 2012, 2013, 2015 and 2017 in the supplied fitment data.

What should I check before ordering?

Check the part number 1986A01031, 24V system voltage, 120A output, internal regulator, twin leg mount, 105mm inside mounting legs, 198mm mount centre to centre, 73mm pulley outside diameter and 8 groove pulley section against the original unit.