National 99363 Engine Crankshaft Repair Sleeve - Rear

National 99363 Engine Crankshaft Repair Sleeve

National 99363 is a stainless steel engine crankshaft repair sleeve built for rear seal repair applications where the crankshaft sealing surface has wear, grooves, or scoring. With a 3.625-inch shaft size and a 4.025-inch flanged outside diameter, this repair sleeve provides a precise service solution for a wide range of Ford, Lincoln, Mercury, Saab, Jaguar, Mazda, and Aston Martin rear applications.

National has supplied sealing solutions for decades, and this part reflects that focus with dimensional accuracy and durable stainless steel construction. The 99363 repair sleeve is a direct-fit service part for rear crankshaft sealing repairs on vehicles such as the Ford F-150, Mustang, Expedition, and Lincoln Town Car.

Key Features

• Engine crankshaft repair sleeve for rear seal service
• Stainless steel construction for wear-resistant surface repair
• Shaft size: 3.625 in. to 3.629 in. maximum, 3.623 in. minimum
• Flanged outside diameter: 4.025 in.
• Installation depth: 1.750 in.
• Overall width: 0.625 in.; width on shaft: 0.500 in.
• National 99363 cross-references Dorman HELP 99363 and Timken KWK99363

Detailed Description

The National 99363 repair sleeve is used to restore a crankshaft sealing surface when the original shaft area has become worn or damaged. Its stainless steel design helps provide a smooth, consistent running surface for the rear seal, supporting proper sealing performance after service. This part is commonly selected for rear crankshaft repair on applications including Ford F-150, Ford Mustang, Ford Explorer, Lincoln Navigator, and Mercury Grand Marquis models, along with select Aston Martin, Saab, Jaguar, and Mazda vehicles.

Because the sleeve is sized to the shaft and flange dimensions listed above, it is important to verify crankshaft measurements before installation. National 99363 is a practical service part for rear main seal repair on high-mileage engines where the sealing surface no longer meets specification.

What It Helps Repair

• Rear main seal leaks caused by crankshaft wear
• Grooved or scored crankshaft sealing surfaces
• Oil seepage at the rear of the engine
• Seal failure after repeated crankshaft surface damage
• Service issues on rear crankshaft sealing applications for Ford, Lincoln, Mercury, Saab, and Aston Martin vehicles

Installation Notes and Tips

Measure the crankshaft sealing surface before installation to confirm it falls within the listed 3.623 to 3.629 inch shaft size range. Clean the shaft thoroughly, inspect the rear seal area for damage, and install the sleeve to the specified 1.750-inch depth. Proper alignment is important to ensure the sleeve seats evenly on the crankshaft and provides a uniform sealing surface.

Fits 2017-2019 Aston Martin DB11, rear; Fits 2010-2019 Aston Martin Rapide, rear; Fits 1999-2019 Ford E-350 Super Duty, rear; Fits 2014-2018 Aston Martin Vanquish, rear; Fits 2005-2016 Aston Martin DB9, rear; Fits 1984-2014 Ford Mustang, rear; Fits 1998-2014 Lincoln Navigator, rear; Fits 1992-2011 Ford Crown Victoria, rear; Fits 1984-2011 Lincoln Town Car, rear; Fits 1984-2010 Ford F-150, rear; Fits 1999-2010 Ford F-250 Super Duty, rear; Fits 1999-2010 Ford F-350 Super Duty, rear; Fits 1999-2009 Saab 9-5, rear; Fits 2002-2005 Jaguar X-Type, rear; Fits 1995-2003 Ford Windstar, rear; Fits 1984-1997 Ford Thunderbird, rear; Fits 1983-1990 Ford Ranger, rear.

Quality Assurance

National has a long history in sealing products and uses engineering support to keep pace with modern vehicle service needs. Part number 99363 is manufactured as a stainless steel repair sleeve for dimensional consistency and dependable rear crankshaft sealing repair.