How to Replace a Corvette Half-Shaft U-Joint

Starting with the 1963 model year, independent rear suspension became standard on all Corvettes, foregoing the solid axles that had been used for the previous decade. The universal joint, or u-joint, made IRS possible. While u-joints had always been used to couple the front of the driveshaft to the transmission and the back of the shaft to the rear differential, now their role expanded to also coupling each rear drive shaft (or half-shaft) to both the differential and the rear wheels. U-joints play a crucial role in the overall scheme of things, since they are responsible, ultimately, for the delivery of power from the transmission to the rear wheels.

While I'm illustrating the replacement of u-joints on a Corvette half-shaft here, remember that u-joints are present on the driveshafts of virtually every rear-wheel-drive vehicle, so these procedures apply to the driveshaft u-joints as well.

Normally, these little workhorses require no maintenance other than a periodic greasing. However, as with all things mechanical, parts eventually fail or wear out. Such was the case with my 1976 customized Corvette. I was cruising along happily at 65mph when I noticed a slight vibration that quickly became very pronounced, accompanied by a loud thumping sound. I immediately pulled over to the side of the road and called a towing service to flatbed the car home. At this point I suspected a u-joint failure, although I didn't know if it was a driveshaft u-joint or a half-shaft u-joint that had given up the ghost. When I got the car home, I discovered that the outboard (wheel side) u-joint on the passenger side of the car had given out. I decided to replace all of the u-joints on both half-shafts, reasoning that if one let go for apparently no good reason, the others also may follow suit eventually. Here's what it took to remove the old u-joints on the half-shafts and replace them with new ones. The procedures are the same for all 1963 and later Corvettes.

Elevate the car by placing the pad of a floor jack beneath the rear spring securing plate.

Once the car is at the maximum elevation the floor jack can give it, place jack stands under the chassis rails just in front of the rear tires. A piece of 1/2" plywood under the jack stands will keep them from digging into the blacktop if you're working in your driveway. Once the jack stands are securely positioned, lower and remove the floor jack.

Put the car in neutral, regardless of whether it has an automatic or manual transmission. This is necessary so that you'll be able to rotate the rear wheels while working.

This is a messy, greasy job so wearing a pair of disposable Nitrile gloves is highly recommended. Use a ratchet and socket to remove the four bolts that hold the trunion (half-shaft flange) to the wheel assembly.

The nuts of the u-bolt that hold the u-joint to the rear differential spline shafts are removed next. A gear wrench definitely makes this task easier, since you'll only have about 7-10º of wrench swing because of the proximity of the struts, spring and stabilizer bar.