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Cocking a rear-mounted timing cover by even a fraction of a millimeter on a Volvo or Mack engine guarantees a stubborn oil leak right over the flywheel housing. The ATC 85109051 Master Alignment Tool delivers the dead-flush plane alignment required to seal the gear cover to the cylinder head perfectly on the first pass.

The Crucial Physics of Rear Geartrain Alignment

Unlike traditional heavy-duty diesels that house their timing gears at the front of the block, Volvo D11 and Mack MP7 engines feature a highly specialized rear overhead geartrain design. Because the timing gears ride inline with the camshaft right at the back of the cylinder head, the timing gear cover must align seamlessly across two separate mating planes simultaneously: the flat back face of the cylinder head and the block deck. When a technician tries to eyeball this cover or slap it down freehand, tightening the bolt pattern naturally pulls the cover slightly unevenly. This creates a microscopic, razor-thin step or lip between the cover edge and the head casting. The liquid gasket compound cannot absorb this uneven displacement under high thermal stress, resulting in chronic oil leaks that travel straight down into the flywheel housing. The ATC 85109051 dual-plate kit solves this structural problem by physically clamping the edges of the cover flat against the cylinder head, forcing it into a perfect, flush horizontal plane as the bolts are torqued down.

• Complete 2-Piece Mechanical Alignment Array – Packed complete with both the left and right alignment block arms (**85109051-A** and **85109051-B**) for comprehensive plane control.
• Direct OEM Factory Tool Interchange – Built custom to match original factory service parameters flawlessly, serving as a high-strength direct functional replacement for tool number **85109051**.
• Absolute Leak and Rework Protection – Forces the timing cover into exact flush positioning to eliminate gasket shear, uneven sealing lip pressure, and premature oil weeps.
• Tailored D11 & MP7 Platform Fitment – Engineered explicitly to bridge the narrow spatial clearances of Volvo D11 and Mack MP7 overhead valve engines.
• Robust Service-Bay Mass Profile – Weighing a highly stable, solid 5.00 lbs, this hardened tool steel fixture set handles high shop use with absolute repeatability.

Stop Eyeballing Your Gaskets. Enforce Dead-Flush Sealing Authority.

The ATC 85109051 Timing Cover Alignment System is a mandatory requirement for independent diesel shops, vocational fleet maintenance hubs, and commercial truck rebuild bays. Don't waste labor doing the exact same tear-down twice—lock your covers flat and seal with total confidence with Apex.

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