1965 Ford Mustang Convertible Rear Axle Rebuild

The pan comes off first, which drains all the fluid. Note the dirty fluid because no one ever changes rear axle lube. For long service, differential fluid should be changed every 30,000 miles along with transmission fluid/filter service. Fluid level should be checked every time you change engine oil.

Deep well 9/16-inch socket removes four axle flange nuts on each side.....

....Axles sometimes come out by hand and they sometimes require a slide hammer.

Carrier bearing caps are removed next using an 11/16-inch socket.

The ring gear/differential package is removed next. Gil Roiz suggests marking bearing caps left and right because both must go back in the same positions.

Pinion flange is removed next to free up the pinion gear, crush sleeve, and bearings.

All bearings and races must be replaced. This bearing race is obviously worse for wear.

Bearings are pressed on in all locations. Here, Gil removes the pinion bearing. Carrier bearings are pressed off the same way.

The ring gear is removed using a 5/8-inch socket.

The side gear tension pin is driven out next to free up the differential pinion pins and gears, also known as "spider" gears.

Differential halves are separated to expose side gears.

These are the differential pinion and side gears. Two pinion gears are supported by the pinion pin, which is secured with a tension pin.

All 7 1/4-inch integral carrier axle housings have a cast-iron center with casting numbers and a date code. This is a C5DW-4025-A casting. The casting date code is January of 1965, a month after Gary's Mustang rolled off the Dearborn assembly line, but as close as we could get it.

After pressure washing and scrubbing the axle housing, Gil preps the surfaces before applying Eastwood's Chassis Black primer and paint.

Gary's 2.83:1 ring and pinion were in perfect condition at 35,000 miles. Look for ring-and-pinion gear types stamped into the gears themselves. The 2.83:1 ratio has 34 ring gear teeth and 12 pinion gear teeth. Mustangs also had 3.20:1 gears with 32 ring gear teeth and 10 pinion gear teeth. The 3.20:1 ratio is more common with three-speed manual transmission cars.

National Parts Depot set us up with brake lines and hoses. We chose galvanized brake lines for originality. Stainless steel may look terrific, but it is an extremely hard metal and can be hard to seal.

Our original Ford brake cylinders were sleeved and freshened up with new rubber by Mustangs Etc. They're as good as new.

Differential side gears are installed along with pinions, getting a fresh coat of assembly lube and thrust washers. The roll pin will be secured with a tension pin.

All moving parts must receive a generous amount of assembly lube. Remember, rear axles run at high temperatures, up to 250-300 degrees, subjecting moving parts to extreme stresses.

The pinion pin tension pin is installed. Check your pinion pin for abnormal wear before reusing. New replacements are virtually impossible to find. Any reputable machine shop can make one from tool steel, but it won't come cheap.

Use a thread locker on all fasteners to ensure security. Torque all fasteners to specifications outlined in the Ford Shop Manual.

The pinion gear bearing has been pressed on and is fitted with a new crush sleeve. Always use a new crush sleeve. This is also called a bearing preload spacer, which loads the bearing and pinion when proper torque is achieved.

Differential carrier bearings are pressed on next.

Pinion bearing races (cups) have been pressed into the housing. The seal is next; it must be lubricated with axle lube around the inside perimeter to ensure a slippery start. Do this dry and you could wind up with a damaged seal and leakage.

The pinion gear is installed along with the yoke. This is the time to set the pinion preload. The nut is torqued until the pinion has 17-27 in. lbs. of preload. This means it should take 17-27 in. lbs. of torque to turn the pinion with new bearings. An important issue here is shims and shim thickness between the bearing and pinion. When you're using a good, used gear set, stick with the shim(s) already with the gear set. If new, you will have to determine shim thickness by temporarily installing the ring and pinion and lapping gears until proper shim thickness is determined. This is a very tedious process.

The ring gear is installed and backlash set using a dial indicator. This determines the backlash between gear teeth. Proper backlash is 0.008-0.012-inch. You want a nice, smooth roll with no binding......

......Any binding means backlash or pinion depth is too tight. Keep in mind that rear ends run very hot. If it binds cold, it will lock up when hot. Get it too loose and it will be noisy and wear out quickly.

Carrier bearing caps have been torqued to 40-44 ft. lbs. with Loctite thread locker. Here, we're installing the adjustment locks.

National Parts Depot provided us with new brake kits and parking brake cables. Aside from the backing plates, which have been reconditioned by Mustangs Etc., these brakes are all new.

The rear axle shaft seals are installed next using The Right Stuff sealer around their perimeters and assembly lube around the inside lip.

The axle shafts have been cleaned and inspected. New axle bearings have been pressed on and we're ready for installation.

The cover is installed using either a gasket or The Right Stuff in a thin bead where it doesn't seep out. Bolts are torqued to 10-17 ft. lbs. If you overtighten these bolts, the cover could leak.