Indian Army Begins Arjun Mk-1 Tank Overhaul After Six-Year Delay, Pilot Project Includes 26 Upgrades

The Indian Army has initiated the long-pending overhaul of its Arjun Mk-1 main battle tanks, beginning with two tanks at the Heavy Vehicles Factory (HVF) in Avadi, near Chennai. The move comes six years after the first Arjun tanks were scheduled to undergo their initial major overhaul.

The two tanks are being taken up under a pilot overhaul programme that will involve a complete dismantling and rebuilding of the platforms. Along with the overhaul, the tanks will receive 26 upgrades derived from the newer Arjun Mk-1A configuration. Procedures developed during the pilot phase are expected to establish the technical and assembly framework for overhauling the remaining 124 Arjun Mk-1 tanks in the Army’s inventory.

The Arjun Mk-1 entered Indian Army service in the mid-2000s, but a full-scale overhaul of the tank had not been undertaken until now. A Comptroller and Auditor General (CAG) performance audit had earlier noted that the first overhaul was due from 2020, while arrangements for carrying out the work had not been finalised. The audit also highlighted shortages of spares and inadequate repair and overhaul infrastructure as factors affecting fleet availability.

While engine-level maintenance had been carried out previously by Engine Factory Avadi and the Defence Research and Development Organisation’s Combat Vehicles Research and Development Establishment (CVRDE), the present programme is the first comprehensive rebuilding effort involving the tank’s hull and turret. Engineers will also have to develop or refine repair procedures for components where complete overhaul documentation is unavailable.

The planned upgrades include six major improvements. These comprise a commander’s panoramic sight, an Mk-II gunner’s main sight, an automatic target tracker, an improved muzzle reference system, new tracks with increased horn height and an advanced running gear system. Other upgrades include an auxiliary power unit, an improved fire detection and suppression system, LED lighting, improved protection against dust ingress and heating elements for the tank’s periscopes.

The overhaul will involve a number of specialised defence facilities and suppliers. The engine is scheduled to be handled by Engine Factory Avadi, while the transmission and final drive will be sent to RENK’s Indian operations. The 120 mm main gun and cradle will be serviced by Advanced Weapons and Equipment India, while the gun control system is associated with Bosch Rexroth in Germany. Several other components, including tracks, batteries, gyros, panoramic sights and fire-detection equipment, are expected to come from Indian suppliers.

One of the major sustainment challenges surrounding the original Arjun Mk-1 has been its dependence on imported components. A 2017 CAG report had estimated that imported content accounted for about 69% of the tank at the time of induction. Changes in the international supplier base over the years have added further complications to sourcing spares and maintaining the fleet.

After the rebuild, the two pilot tanks are expected to undergo hull and turret stand testing, stability checks and running trials. These will be followed by limited validation trials at the Pokhran field firing range. The overhaul programme carries a warranty of 24 months or 150 engine hours, whichever comes first.

The Army currently operates 124 Arjun Mk-1 tanks, inducted between 2004 and 2010, with the fleet deployed with the 43rd and 75th Armoured Regiments in Rajasthan’s desert sector. Separately, the Army has an order for 118 Arjun Mk-1A tanks placed with HVF in 2021, although their deliveries have faced delays, with engine availability identified as a key bottleneck.

The launch of the pilot overhaul marks an important step in establishing a structured lifecycle-support system for India’s indigenous main battle tank. Beyond restoring individual vehicles, the programme is expected to create standardised overhaul procedures that can be applied across the wider Arjun Mk-1 fleet, while incorporating selected improvements developed for the Mk-1A.