HOW TO SERVICE CV JOINTS
— Inspect, clean and service or add longer axle shafts —
We are building a RZR project with LoneStar Racing long-travel suspension. The LSR long-travel kit widens the machine, so we needed longer axle shafts inserted into the stock CVs. The steps we followed will allow you to check the condition of the CVs, determine if they are in good shape and grease the parts for reassembly. This is a dirty job, so you need paper towels, chemical-resistant disposable gloves, CV grease and CV boot bands.
If you buy aftermarket replacement boot kits, they come with the bands and the grease. You can order the CV grease from an auto parts store. It comes sealed in a plastic bag, with one bag needed for each joint. None of our local stores had more than two bags, so be prepared to wait for it to be ordered. Living in a big city, it only takes a few hours. You will also need some CV banding tools, a brass or aluminum drift punch, snap ring pliers and a variety of other hand tools.
1. Most CV joints are secured with stainless steel clamps that are not reusable. There are special banding cutters that snip right through the metal bands. The ends of the cutting jaws are hooked, so with a little care, you can cut without injuring the boot.
2. Now for the dirty part. After you cut the bands at both ends of the boot, slide the boot up the axle shaft so it is out of the way. The black CV grease is specific for CVs. You can’t use just any grease.
3. An internal spring clip prevents the CV joint from pulling apart. Clean out enough grease to see what you are doing. When you can see the clip, it is easy to use a small-blade screwdriver to pop it out.
4. We are working on the differential side of the axle here. When the clip is removed, the CV ball bearings and race will pull right out of the CV cup. The balls run in the long slots machined into the inside of the cup.
5. It is easy to remove the balls from the race. They may need a little help with a small screwdriver. Keep track of the balls so you can clean, inspect and reuse them if they check out okay.
6. With the race slid back, clean enough grease off the end of the axle to expose the snap ring. Use snap-ring pliers to carefully remove the snap ring without stretching or bending it in any way.
7. With the snap ring removed, the inner and outer races of the CV will slide right off of the end of the axle. You may also remove the boot at this time. If the boot is in good shape, it can be used again.
8. You will need to clean all the parts in order to inspect them for damage and wear. A clicking or popping sound in the CV can signal that the outer race has cracked. From a distance, these parts all look good.
9. The inside of the race is shiny in spots (1), the outside of the race has a band where the original finish shows light, insignificant wear (2). The balls are leaving small witness marks (3) in the race openings as well.
10. The inside of the CV cup shows the most apparent wear. This still isn’t bad, but it is a spot that bears keeping an eye on in the future. As the suspension travels up and down, the axle must make changes in length. The cup makes that possible. It makes sense that the most wear is in the middle.
11. Slide the boot and inner and outer races back on the axle. Snap rings are stamped, so the edges on one side are sharper than the other. The sharp edge should face the end of the axle. This is the new, longer LSR long-travel axle. The groove is to release pressure from the boot.
12. This photo is with the snap ring installed and the balls going back in the race. We are just test fitting them here. We will grease the inner race before installing the CV bearing’s balls for real.
13. Cut one corner off the grease bag and grease up the bearing and races. Try to avoid getting more grease on the axle shaft than you have to. The boot needs to lock into place over the groove ground in the axle, so you don’t want grease there.
14. Use all of the grease left in the CV grease bag to fill the CV cup up with fresh grease. It will spread itself around fine when you insert the bearing into the cup. There is no need to pack it in there at this point.
15. Push the bearing into the cup. You may need to pack the grease in enough to expose the internal spring-clip groove. The clip is easy to install. Using a new clip is good practice, but make certain it has enough spring to fit snugly in the groove.
16. Here is the one side of the axle all assembled and ready to have the boot installed. The inside of the boot has to be clean and free from grease. The axle and the boot surface on the cup must be cleaned with something like contact cleaner or carb cleaner to make a good mating surface.
17. Here the boot has been successfully slipped onto the CV cup without getting any grease on the sealing surfaces. If you get grease under the lip of the boot, it can pull off while you are driving. A little extra care here will pay off down the trail.
18. Slide the axle end of the boot up so that is located between the ridges formed into the axle. This axle has a groove to keep pressure out of the boot. If you are working with the stock axle, slide a zip-tie under the lip of the boot. Work the joint to all angles and slide it in and out before removing the zip-tie.
19. The hub end of the axle is made a little differently, but the inner and outer races are much the same. This end uses a spring clip, so you pull the boot back and use an aluminum or brass punch against the inner race to knock the stub axle off the shaft.
20. Again, you clean and inspect all of the parts, but most people suggest leaving the bearing intact rather than pulling it apart. Ours was in good shape, but this is what the joint cup looks like when it is worn out. The balls have worn right through the surface of the steel.
21. Grease everything like on the opposite side. Carefully line the splines in the stub axle up with the axle splines. Drive the stub on with a dead-blow plastic hammer. Use a banding tool (ours is from Tusk) to snug up the band, then bend it over. Use a small hammer to bend the band and tabs over. Then trim the excess band off. Do the same for all the boot joints.
At this point the axle should be ready to install on the machine. If you are just doing a service, then the CVs should be loving the new grease. In our case, where we were upgrading the suspension travel, we are ready to continue the build. The first axle you rebuild will be tedious and dirty, but nothing here is especially difficult, and only fairly routine tools are needed. The exception are the band cutters and banding tool. The ones we got from Rocky Mountain ATV/MC (www.rockymountainatvmc.com) were around $20, and they worked great.