[D2] CV Joint Trail Fix

[rmuller]

CV Joint Trail Fix
By SCSL;

As prices on Discovery II’s continue to go down, more and more people are getting more & more aggressive in building up & wheelin’ their Disco’s. As such, many of us are running into more complicated recovery & breakage situations. Any Four Wheeler, or group of Four Wheelers, should have the basic parts necessary to make trail repairs. This includes the right tools, and the right spares. An economical way to accomplish this, for those that tend to travel in the same group, is to pool resources to purchase specific spare parts for those most likely to break on the trail. Those who typically drive the only Disco II in the group they wheel with may have a larger investment ahead of them.

The reality, however, is that we wheel on a budget. Given the premium we pay for upgrades, modifications, and bolt-on’s, our budget is often very tight, and may not include spare axle shaft / CV assemblies for both sides.

As Disco II’s grow in size, so does the risk of breakage: specifically to driveline & suspension components. Among the weak links of the built Discovery II are the CV joints. While a grenaded CV may ruin your trail run, it need not leave you stranded.
First, find level ground. If you are on the approach-end of an obstacle, back down. If you are mid-way through, either winch out or get towed out. If you are on an inclining or declining section of trail, do not side-slope yourself (ie: do not turn perpendicular to the trail). Proceed to relatively level ground; this will be possible in the overwhelming majority of situations.

To perform the field fix necessary to limp home, you’ll need the following tools: 2 hi-lift jacks (you’ll probably have 2 among the group, but worst case you can use one), 1 jack stand, wheel chocks, a 1 ¼” (32mm) socket, breaker bar, combination wrench set, allen wrench set, duct tape, shop rags, a knife (utility knifes work best but a pocket knife will do the job), a wedge or chisel, and both hard rubber (not necessary but nice to have; easy on parts) and metal mallets. It’s nice to have a socket set, and speeds up the job, but it’s not absolutely necessary. The biggest challenge will be removing the hub nut. This nut is torqued to over 200 ft/lbs and should not be removed with the vehicle jacked up. First, take the handle off one of the high-lift jacks. Use the handle as a leverage sleeve over the breaker bar handle facing towards the front of the vehicle. Position the socket so that the breaker-bar handle/hi-lift handle are at approximately 45 degrees. Stand on the hi-lift handle and push down while pulling up on the driver’s side tubing of your front bumper bar. If you don’t have a bull bar on your bumper it will be a little tougher, but not impossible. It may take you numerous attempts before the nut loosens; you will have to give it plenty of umph.

Once the hub-nut loosens. Loosen up the lug-nuts, use the other Hi Lift to jack the vehicle from the front end of the rock slider, and place a jack-stand underneath the driver’s side axle tube for safety. It’s always safe to chock the rear wheels when the front is lifted. Remove the wheel, exposing the rotor. (Those of you that have changed your brakes know that there is a small screw on the rooter that attaches it to the hub. Typically, you have to drill out this screw to replace the rotor. I would strongly suggest not replacing this screw for those who drive their Disco off-road. The screw does not do much for you, and unless you carry a drill with you, it will make removing the rotor on the trail impossible most of the time.) Remove the caliper & place it out of the way on the radius arm; no need to remove the brake lines. To remove the rotor, tap it firmly with the rubber mallet until it loosens up & comes off, exposing the hub. The ABS line will be attached to the hub. Do not attempt to pull the ABS line out! If you look closely, you’ll see a small allen-head screw near the connection. Unscrew it with an allen wrench until the ABS sensor slids easily out. Separate the hub by unscrewing the 4 bolts, the rubber mallet may work well with the wrench here to get them off as they are on quite tight (and should be replaced as such). To coax the hub into separating, you may have to employ a chisel/wedge. Tap firmly, but do not pound the hub into submission as damage may occur. Alternate between tapping the hub, and tapping the chisel into the seam. Remove the hub to access the CV joint/stub-axle assembly. When handling the rubber gaiter, you’ll notice loose bits of your grenaded CV joint. When you open up the assembly, be careful not to stick your fingers into the rubber gaiter to survey your damage. The pieces may be very sharp and you may slice your finger (ask me how I know this….). You may now remove the axle shaft – the entire CV joint/shaft assembly will slide out. Note that your axle will be up on the jack-stand, so there should be minimal leaking.

The rubber gaiter is more-or-less permanently attached to the stub. Use the knife to cut the gaiter from the stub & clean away whatever grease remains. Now that you’ve taken the whole kit apart, putting it together will be a fairly simple reversing of the process. There are three main considerations in putting it back together. First, pour some 90-weight down the axle tube. It seemed to me that I lost quite a bit, so I poured in roughly a quart. Stuff 2 shop rags down the axle tube. Put a third around the cup & secure it firmly with duct tape. Do not be afraid to use too much duct tape. Second, ensure you put the stub shaft/wheel bearing back in!! This is the only thing holding your hub & wheel assembly together. Finally, reverse the disassembly process as it regards the hub, rotor, caliper, etc, & ensure your hub nut is cranked on tight.

Before driving, lock your center diff. Do not remove the front driveshaft - it is not necessary & may damage your differential gears. You are now ready to limp home in rear wheel drive. Stop every so often to check your hub nut & ensure it does not loosen up. Your hub nut loosening would be EXTREMELY dangerous, so err on the side of caution. It goes without saying that, as you limp off the trail, your performance will be severely effected by being in rear wheel drive. Drive as conservatively as possible and stay behind another vehicle at all times in case you need to be towed thru an unavoidable obstacle (rock, mud, water, etc).

Once you get back to your spare, whether it’s at home, at the shop, or back at camp, you can replace the CV joint / axle shaft by the same procedure, though hopefully with the help of floor jack. Brush some anti-seize on the splines of the new stub shaft before reattaching the hub, wheel, and hubnut. You may notice some shrapnel when you drain your diff fully. I would suggest running a telescoping magnet throughout the axle tube from the side you broke; this will pick up additional metal. Finally, once you replace the CV joint & refill the differential, drive around for about a week, and then drain & refill your diff again. This should help clean out any remaining debris from the field repair. Provided you have cranked the hub-nut as tight as humanly possible, you can drive home in rear wheel drive if you don’t have immediate access to a spare. Again, stop every so often & check that hub-nut visually. Stay under 55 mph. Drive conservatively and you’ll make it home with no problem. Once you’ve made this repair, it’s fairly straight forward.