8-Inch Ford Rear End Torque Specifications
by Robert BaylyThe 8-inch Ford rear axle was used from the early 1960s to 1980 in small and mid-size passenger cars with six- and small-block V-8 engines. The 8-inch rear axle looks very much like the popular Ford 9-inch rear axle. Both axles use a third member that contains the differential, which is made up of the ring and pinion gear, spider gears and various bearings. The third member fits in a banjo-type axle housing that does not have a rear cover.
Bearing Cap Bolts
The bearing cap bolts attach to the back of the third-member – also called a carrier – housing. They hold in the bearings that support the differential case. The torque for these bolts is between 70 and 85 foot-pounds.
Bearing Adjusting Lock Nut Bolt
These bolts lock down the adjusting nut for the differential case bearings. The torque for these bolts is between 12 and 25 foot-pounds.
Carrier Housing Stud Nuts
The axle housing has 10 studs in it that the third member fits on. The nuts hold the third member onto the axle housing. The torque for these is between 25 and 40 foot-pounds.
Pinion Retainer-to-Carrier Bolts
The pinion retainer fits over the pinion gear and attaches to the front of the third member. These bolts hold the retainer onto the third member. The torque for these bolts is between 30 and 45 foot-pounds.
Ring Gear Attaching Bolts
These bolts attach the ring gear to the differential case. The torque for these bolts is between 70 and 85 foot-pounds.
Minimum Torque to Tighten Pinion Nut for Pinion Bearing Preload
A certain pressure -- or preload -- on the pinion bearing and spacer must be established. This is done by tightening the pinion nut to a minimum torque value, then attempting to turn the pinion nut and reading the amount of torque needed to turn it through several revolutions. If the minimum torque needed to rotate the pinion nut is not established by the minimum nut torque, the nut must be tightened further, in small increments, until the proper torque value is established. The minimum torque is 170 foot-pounds. If the preload exceeds the specification at minimum torque, a new spacer must be installed on the pinion gear.
Pinion Bearing Preload
A spacer fits on the end of the pinion gear. There are two types of spacers, collapsible, and solid. The spacers can be reused, but the collapsible spacer has different values for new and used. The torque for a new collapsible spacer is between 17 and 27 inch-pounds. The torque for used collapsible spacer is between 8 and 14 inch-pounds. The torque for a solid spacer is between 13 and 33 inch-pounds. Note that these measurements are in inch-pounds and require an inch-pound torque wrench. All preload values are with a new oil seal installed in the pinion retainer.
References
- Mitchell Vintage Repair Manuals, Rear Axles Ford Motor Co, Separate Housing; The Mitchell Repair Information Company; 2003
- Hemmings: Ford 8-inch Third Member Carriers
Writer Bio
Robert Bayly, based in Apple Valley, California, began writing in 2010, his "how to" articles can be found on eHow. With more than 15 years in the auto industry, Bayly has been an auto and diesel mechanic, service writer and parts manager. He received certificates from Pontiac (parts system), Cat Diesel (engine service), Saab and Fiat (parts- warranty system).
