There are five types of universal joints used: the Cardan cross-type with U-bolts and snaprings; a Cardan cross-type with just snaprings; a double Cardan cross-type; ball and trunnion-type universal joints which serve as a combination slip-joint and universal joint. Some models have a front driveshaft which, at the transfer case end, uses a double offset joint. This unit is not repairable and must be serviced by replacement only.
Universal joints fail for numerous reasons, the primary one being lack of lubrication. Others could be structural damage incurred from hitting something, an unbalanced driveshaft, the entrance of dirt or water due to a rotted rubber seal or just plain wear from excessive mileage.
Rebuilding kits are available for both types of universal joints. The kit for a Cardan cross-type universal joint includes the entire cross assembly, the cross bearing journal, roller bearings, bearing cap with new rubber seal and new snaprings.
The rebuilding kit for the ball and trunnion-type universal joint includes a new grease cover and gasket, universal joint body, two centering buttons and spring washers, two ball and roller bearing assemblies, two thrust washers, dust cover and two dust cover clamps.
Although U-joints can be rebuilt, most procedures today call for replacement rather than rebuilding.
Cardan Cross Type with Snaprings
See Figure 1
- Remove the driveshaft from the vehicle.
- Remove the snaprings by pinching the ends together with a pair of pliers. If the rings do not readily snap out of the groove, tap the end of the bearing lightly to relieve pressure against the rings.
- After removing the snaprings, press on the end of one bearing until the opposite bearing is pushed from the yoke arm. Turn the joint over and press the first bearing back out of that arm by pressing on the exposed end of the journal shaft. To drive it out, use a soft ground drift with a flat face, about 1 / 32 in. (0.8mm) smaller in diameter than the hole in the yoke; otherwise, there is danger of damaging the bearing.
- Repeat the procedure for the other two bearings, then lift out the journal assembly by sliding it to one side.
- Wash all parts in cleaning solvent and inspect the parts after cleaning. Replace the journal assembly if it is worn extensively. Make sure that the grease channel in each journal trunnion is open.
- Pack all of the bearing caps 1 / 3 full of grease and install the rollers (bearings).
- Press one of the cap/bearing assemblies into one of the yoke arms just far enough so that the cap will remain in position.
- Place the journal in position in the installed cap, with a cap/bearing assembly placed on the opposite end.
- Position the free cap so that when it is driven from the opposite end it will be inserted into the opening of the yoke. Repeat this operation for the other two bearings.
- Install the retaining clips. If the U-joint binds when it is assembled, tap the arms of the yoke slightly to relieve any pressure on the bearings at the end of the journal.
See Figure 2
- Removal of the attaching U-bolt releases one set of bearing races. Slide the driveshaft into the yoke flange to remove that set of bearing races, being careful not to lose the rollers (bearings).
- After removal of the first set of bearings, release the other set by pinching the ends of the snaprings with pliers and removing them from the sleeve yoke. Should the rings fail to snap readily from the groove, tap the end of the bearing lightly, to relieve the pressure against them.
- Press on the end of one bearing, until the opposite bearing is pushed out of the yoke arm.
- Turn the universal joint over and press the first bearing out by pressing on the exposed end of the journal assembly. Use a soft round drift with a flat face about 1 / 32 in. (0.8mm) smaller in diameter than the hole in the yoke arm. Then drive out the bearing.
- Lift the journal out by sliding it to one side.
- Install in the reverse order of removal, using the procedures for the snapring U-joints from Step 4 on as a guide.
See Figure 3
- Use a punch to mark the coupling yoke and the adjoining yokes before disassembly, to ensure proper reassembly and driveline balance.
- It is easiest to remove the bearings from the coupling yoke first.
- Support the driveshaft horizontally on a press stand, or on the workbench if a vise is being used.
- If snaprings are used to retain the bearing cups, remove them. Place the rear car of the coupling yoke over a socket large enough to receive the cup. Place a smaller socket, or a cross press made for the purpose, over the opposite cup. Press the bearing cup out of the coupling yoke ear. If the cup is not completely removed, insert a spacer and complete the operation, or grasp the cup with a pair of slip joint pliers and work it out. If the cups are retained by plastic, this will shear the retainers. Remove any bits of plastic.
- Rotate the driveshaft and repeat the operation on the opposite cup.
- Disengage the trunnions of the spider, still attached to the flanged yoke, from the coupling yoke, and pull the flanged yoke and spider from the center ball on the ball support tube yoke.
The joint between the shaft and coupling yoke can be serviced without disassembly of the joint between the coupling yoke and flanged yoke.
- Pry the seal from the ball cavity, remove the washers, spring and three seats. Examine the ball stud seat and the ball stud for scores or wear. Worn parts can be replaced with a kit. Clean the ball seat cavity and fill it with grease. Install the spring, washer, ball seats, and spacer (washer) over the ball.
- To assembly, insert one bearing cup part way into one ear of the ball support tube yoke and turn this cup to the bottom.
- Insert the spider (cross) into the tube so that the trunnion (arm) seats freely in the cup.
- Install the opposite cup part way, making sure that both cups are straight.
- Press the cups into position, making sure that both cups squarely engage the spider. Back off if there is a sudden increase in resistance, indicating that a cup is cocked or a needle bearing is out of place.
- As soon as one bearing retainer groove clears the yoke, stop and install the retainer (plastic retainer models). On models with snaprings, press the cups into place, then install the snaprings over the cups.
- If difficulty is encountered installing the plastic retainers or the snaprings, smack the yoke sharply with a hammer to spring the ears slightly.
- Install one bearing cup part way into the ear of the coupling yoke, Make sure that the alignment marks are matched, then engaged the coupling yoke over the spider and press in the cups, installing the retainers or snaprings as before.
- Install the cups and spider into the flanged yoke as with the previous yoke.
- Remove the driveshaft from the vehicle.
- Position the tube of the driveshaft near the ball-type universal joint, in a bench vise; clamp tightly.
- Bend the lugs of the grease cover away from the universal joint body and remove the cover and the gasket.
- Remove the two clamps from the dust cover. Push the joint body toward the driveshaft tube. Remove the two centering buttons and spring washers, the two ball and roller bearings and the two thrust washers from the trunnion pin.
- Press the trunnion pin from the ball head with an arbor press.
It is strongly recommended that the trunnion pin be pressed out and in by an arbor press because of the possible damage that could result from other methods such as hammer and drift. This is a critical component in the assembly and any damage could result in premature failure or even necessitate replacement of the entire driveshaft.
- Clean the ball head of the driveshaft with a suitable solvent and dry thoroughly.
- Secure the larger end of the dust cover to the universal joint body with the larger of the two clamps. Install the smaller clamp at the smaller end of the dust cover, then fit the cover over the ball head shaft.
- Push the universal joint cover toward the driveshaft tube.
- With an arbor press, press the trunnion pin into a centered position in the ball head.
The trunnion pin must project an equal distance from each side of the ball head. If it is not centered within 0.006 in. (0.15mm), driveshaft vibration may result.
- Hold the universal joint body toward the tube of the driveshaft to gain access to the trunnion pin. Install one thrust washer, one ball and roller bearing and one spring washer at one side of the ball head. Compress the centering buttons into the trunnion pin, then move the joint body away from the driveshaft tube, into position to surround the buttons and to hold them in place.
- Insert the breather between the dust cover and ball head shaft, along the length of the shaft. The breather must extend no more than 1 / 2 in. (13mm) beyond the dust cover, along the shaft. Tighten the clamp screw to secure the cover to the shaft. Cut away any portion of the dust cover which protrudes from beneath either clamp.
- Pack the raceways of the universal joint body (inner surfaces which surround the ball and roller bearings) with about 2 oz. of universal joint grease. Divide the grease equally between the raceways. Position the gasket and grease cover on the body of the universal joint and bend the lugs of the cover in place. Move the body inward and outward, toward and away from the driveshaft tube, to distribute the grease in the raceways.
- Install the driveshaft on the vehicle.