My 68 Mustang coupe’s Ford 8 inch rear axle bearings started groaning about a week ago and have been growing louder by the day. The wail of a bearing contemplating suicide is a sound I fear since the day an exploding wheel bearing left me stranded on a narrow shoulder of the Staten Island Expressway. So I addressed it as soon as I was able.
With a little patience and the right tools, it’s actually fairly simple to replace Ford 8 inch rear axle bearings. If the bearings in your old Ford are howling in despair, here’s what you’ll need to do – preferably sooner rather than later.
First, with the front wheels secured with chocks, and the back end of the car up on sturdy jacks, remove your rear wheels and brake drums. Next, remove the four bolts holding the axle retainer plate on. There is a hole in the axle flange that will allow you to access the bolts with a socket. Be aware that those four bolts also secure your brake backing plate to the axle, so you’ll want to take care not to damage the wheel cylinders and brake lines while everything is loose. You don’t need to remove the brakes in order to get the axle out.
With those four bolts removed your axle will slide out, though it will probably need to be coerced. If you can’t pull it out by hand you can flip your brake drum around, attach it loosely with three or four lug nuts and use it as a makeshift slide hammer to jar the axle splines out of the carrier. If that doesn’t work you’ll need to use an actual slide hammer with an axle flange adaptor. My axles were not happy about coming out, so I needed the real deal slide hammer. If you don’t have one, many auto parts stores will loan you one for free.
The axles are different lengths, so mark which side each came from so they don’t get mixed up. Ford 8 inch rear axle bearings and the bearing retainers are press fit, so you’ll need to drop your axle shafts off at a competent machine or mechanic shop to have the old bearings and retainers removed and new ones pressed on. There are methods of removing and installing bearings and retainers at home and without a press, but in my opinion it’s worth a few extra dollars to have someone with the proper equipment handle this step rather than risk damaging the new bearings and having to do the job all over again.
New axle seals cost about five bucks per side, so it really doesn’t make sense to do all of this work and not replace them while everything is apart. The seals come out easily with a seal puller attachment on the slide hammer. I didn’t have that attachment available to me, so I had to remove the seals the old fashioned way.
With a hammer and sharp chisel, knock two or three cuts into the old seal, being careful not to cut down into the axle tube. With the seal compromised you should be able to pry it out with a seal puller hook or screwdriver without too much trouble. Once the seals are out, clean the surfaces as well as you can.
Before you install the new axle seals wipe a bit of gasket sealer on the outer surface of the ring. Then line the seal up inside the axle tube as square as you can make it and hammer the seal into place with a bearing and seal driver. If you don’t have a bearing and seal driver set, most auto parts stores will loan you one. The driver you use should be the same diameter as the seal’s steel body. Wipe away any gasket sealer left inside the tube.
Now you’re ready to slide your axle shaft back in. Before you reinstall the axle, check the rubber part of the axle seal for damage, ensure the seal spring is still attached, and confirm you have the correct axle for the side you’re working on. I also like to smear some bearing grease on the rubber seal to provide some lubrication for the axle sliding through it. Slide the axle in until you feel the splines match and the bearing center in the axle tube. You probably won’t be able to push the axle all the way back in by hand. Once it’s all lined up you can smack the axle flange with a rubber mallet or dead blow hammer to drive the shaft all the way in. If you don’t have one of those you can hold a scrap of 2×4 against the flange to soften the blow and drive the axle in with a regular hammer.
With the axle installed, reinstall and torque down the four backing plate/retainer plate bolts. Re-install the brake drums and wheels, and go for a quiet drive with no bearing noise!