The outer constant velocity joint (CV joint) boots commonly fail on the B5 Passat and A4 (seems more often than most makes). The rubber boot is responsible for keeping the CV joint surrounded by grease - a tear in the boot will permit grease to fly out of the boot when the wheel is in motion, leaving tell-tale residue around the inner perimeter of the wheel (for the outer boot). Left like this, dirt will enter the joint, turning the bearings of the CV joint into grinders and destroying the CV joint. If you hear a clicking noise when in motion and while turning the car, the CV joints will need to be replaced. If a CV joint needs to be replaced, it's often less expensive to simply purchase a rebuilt driveshaft, as from Raxles. This also makes for easier replacement.
|Thanks go out to a B5er who caught an omission of the inner CV joint gasket present only on '98-01 1.8t manual models, corrected. Updated boot kit part numbers for current models.|
Part Information & Sources:
Note - always confirm part numbers by looking at the actual part mounted in the car! Mistakes will happen sometime, somewhere.
|Outer CV Boot Kit
|AEB, ATW, AUG engines||3B0 498 203 A|
|AHA, ATQ engines||441 498 203 A|
|AWM, ATQ 2WD, ATQ 4WD (manual), BDP||441 498 203 A|
|ATQ 4WD (automatic)||4A0 498 203 C|
pre VIN 3D-3E312500 or 3B-3-402000
|441 498 203 A|
|AWM 2WD, ATQ, BDP (manual)
post VIN 3B-3E312501 or 3B-3-402001
|3B0 498 203 D|
|AWM 4WD, BDP (automatic)||3B0 498 203 D|
|ATQ 4WD||4A0 498 203 C|
Inner CV joint gasket
|'98-01||AEB, ATW, AUG (manual)||8D0 407 309 A|
OEM Pricing: ~$25-$35
Adirondack Auto Brokers: $16-$26
- 14mm socketed hex driver (17mm for V6 engines) finally updated!
- 6mm allen key or socketed hex driver
- 10mm 12-point star (triple square) driver
- 10mm combination wrench
- 10mm socket
- CV boot clamp tool
Note - if you're in the US, AutoZone carries the large hex drivers, 12-point drivers, and boot clamp tool. A cheap boot clamp tool is available ($8) - used for this job as I wasn't planning on doing this more than a few times.
While the CV boot can be replaced with the driveaxle in the car, it's easy enough to remove the axle and work on the CV joints comfortably.
- With the car on the ground, start by loosening the wheel lug nuts.
- Loosen the driveaxle bolt with the 14mm hex driver (17mm for the V6). The driveaxle bolt, by necessity, is highly torqued - you'll need to use quite a bit of force to loosen the bolt. The force necessary for tightening highly stresses the bolt, and is the reason why a replacement bolt is provided in the boot kit.
- Raise the front of the vehicle (use jackstands, of course).
- Not necessary, but you can improve access to the driveaxle by removing the brake disc rotor and hanging the brake calipers. (illustration)
- Follow the driveaxle to the inner CV joint/transmission mating bolts. You'll need a 10mm 12-point star driver to remove the 6 bolts. If you're working on the passenger side of the vehicle, you'll need to rotate the shaft to access all of the bolts, or remove the protective overhanging plate (held in place by three 6mm allen bolts). On models with a gasket on the inner CV joint (see parts list), remove the gasket and clean the mating surfaces. (illustration)
- Haynes recommends hanging the driveshaft to keep the outer CV joint from overflexing - rope, string, etc.
- At the wheel hub, pull out the wheel speed sensor, located near the brake calipers - this step is often overlooked at auto shops. On these cars, pulling out the driveaxle with the wheel speed sensor in place will destroy the sensor and require replacement. (illustration)
- Now to removing the upper control arms from the steering knuckle. Start by removing the 10mm bolt and nut clamping the the upper control arms in the steering knuckle with the 10mm socket wrench and socket.
- The really fun part - pull the upper control arms from the steering knuckle. On my car, the control arms didn't want to leave their home in the knuckle. About a half hour of tender, loving care (read: small sledgehammer and brass point) later, the control arms popped out. I used a blunt tool to push the end of the control arm joints upwards through the steering knuckle. It's tempting to pry open the steering knuckle cavity at the visible slots - resist this. Deforming the fit between the control arms and steering knuckle is a good way to create a wobbly drive. Also, take care not to damage the balljoint boots - standard balljoint pry bars will likely destroy destroy the boots, necessitating control arm replacement (gripe - this is a needlessly expensive way of replacing balljoints! Terrible design choice to keep the balljoint a permanent part of the control arm).
- Completely remove the driveaxle bolt.
- With the upper control arms removed, the steering knuckle will freely move around - move the assembly away from the car and you'll be able to pull the driveaxle from the wheel hub. Gently tapping the driveaxle from the outside of the wheel hub can help with removal.
- The driveaxle has now been removed from the car. (illustration)
Note - If you'll simply be replacing the driveaxle, skip down to installation.
CV boot replacement:
- With the driveaxle removed, clamp it in place with a vise, or other means of holding the driveaxle securely. Use rubber grips or cloths when clamping to keep from deforming the shaft. (illustration)
- Pry the two boot clamps open and cut off the old boot. This will expose the CV joint. (illustration)
- Time for some fun - the CV joint needs to be driven from the driveaxle shaft. One method is to use a hammer to drive off the joint - use a soft metal piece (brass works well) to direct the hammer's force at the innermost portion of the CV joint.
- Note the installation and orientation of the thrust washer, dished washer, and circlip - these will need to be reinstalled in the same order later. Take care with the thrust washer, as a replacement is not supplied in the boot kit.
- With the joint removed, clean off as much grease as possible, and mark the alignment of the inner race, bearing cage, and joint housing.
- The bearing cage can be moved around to expose each bearing for removal - push down on one edge of the cage to bring the opposing bearing out of its races.
- The inner race can then be removed from the bearing cage - twist the inner race in the cage and you'll be able to remove the race.
- Clean off all parts. (illustration)
- Examine for joint damage. Both outer joints of my B5 had some damage, due to dirt entry. One simple solution for two slightly damaged outer joints is to swap the joints - the damage is typically restricted to one edge of the joint where the individual bearings place the highest load. Swapping the joints will place the bearings to work against the undamaged sections of the joint surfaces. (illustration)
- Coat all surfaces with fresh CV joint grease.
- Reassemble the joint, and fill with as much grease as possible. Completely packing the joint is important.
- Use tape (duct, electrical, masking, etc) to cover the driveaxle splines.
- Slide the small boot clamp onto the drive axle, followed by the new boot.
- Remove the tape, and slide on the dished washer and thrust washer. Install the replacement circlip.
- Add the remainder of the grease to the empty boot.
- Tap the joint onto the driveshaft, until engaged by the circlip.
- Slide the boot onto the joint, using the boot clamp tool to secure the small and large clamps.
- If your inner joint had a gasket, ensure the mating surfaces are clean and apply the new gasket.
- Insert the driveaxle outer end into the steering knuckle, using the new bolt provided to tighten the joint just enough to move the joint into place.
- Reinstall the upper control arms, tightening the clamping nut to 30 ft-lbs / 40 Nm.
- Reattach the inner end of the driveaxle to the transmission housing, tightening the bolts to 59 ft-lbs / 80 Nm, working in a star pattern to tighten the joint equally.
- Reinstall the brake rotor and calipers if removed previously.
- Reinstall the wheel, tightening the lug nuts by hand.
- Lower the car.
- If the replacement driveaxle/hub bolt is a 14mm hex, tighten to 85 ft-lbs / 115 Nm with a torque wrench. Then switch to a breaker bar (ratchetless socket wrench with a cheater bar, etc) to tighten the bolt an additional 1/2 turn. Note that the final tightening is not something you want to subject to a ratcheting mechanism. A 17mm hex bolt should be tightened to 140 ft-lbs / 190 Nm + 1/2 turn.
- Tighten the lug nuts to 89 ft-lbs / 120 Nm, working in a star pattern.