I’m looking at picking one of these up for about $1500 for a metro commuter car and they said the CV joint needs replacement. Is this something a mechanically inclined person could do in their garage?
IIRC, Sentras use a tripod joint which you can’t disassemble because bits of it are welded together; you need to replace the whole shaft, which is a) lots of work, and b) a lot more expensive bits-wise.
That may only apply to the '91-'94 model, though. If you call a Nissan dealer they’ll tell you whether the '96 has the tripod joint or not.
Replacing CV joints and/or half-shafts is normally beyond the means of a driveway mechanic, unless they have things like large arbor presses and pneumatic tools, plus the ability to do an alignment job.
Call around to a couple local clutch shops. They often do this kind of work.
The last time I needed a CV joint, they pulled the entire front axle and replaced it, because its so much faster, that you save enough money on labor that it actually comes out cheaper this way.
Even “Extreme How-to” agrees…
*Replacing the entire drive axle assembly is much more efficient than servicing the boots and CV joints. *
I recall getting a quote for $300 in Michigan, but ultimately the work was done in a rural area of Virginia for $200.
(edited to add: it was a Mazda 626, '93 or so, that I picked up for $1,000.)
It’s not that tough a job. You’ll need a socket for the axle nut (pretty big size, won’t be in any standard home tool kit). You should use a torque wrench for it and the strut-to-steering knuckle bolts. Once those fasteners are removed, you work the knuckle off the end of the axle, then pry the axle out of the tranny. Be very careful not to nick the tranny side seal with the splines on the inboard end of the axle. Jack the side of the car up as high as you can to minimize lost tranny fluid. On reassembly make sure the axle engages fully into the tranny.
Now to educate:
Tripod joints are used for inner CV’s, and every one I’ve seen can be disassembled. Rzeppa joints are used for outer CV’s, and can be disassembled if removed from the axle shaft. However, some axles are constructed such that one (or both) of the joints cannot be removed from the shaft.
The standard repair nowadays is to replace the entire axle shaft assembly with a remanufactured one. This costs less for parts AND labor than replacing just the joint itself (only offered as new, if available separately at all).
Presses are not needed at all. Pneumatic tools make things easier and quicker, but are not necessary. Realignment is generally not required.
Average price for the ones I do is 250.
Gary For the average DIY this job would be either very difficult or damn near impossible, IMHO.
If the OP lives where they salt the roads, the axle may take many tons of pressure to remove. To remove the steering knucle will require a pickle fork, as may the lower ball joint.
then once the shaft is out, The joints have to be separated. This can require a BFH and can be a very messy job.
Gotta disagree here, with the possible exception of the salt situation.
Roads in my area are salted sometimes, but not extensively. Most axles come out of the hub by hand or with a few taps from a soft-faced hammer. A few require a three-legged puller, which can be rented.
The steering knuckle is unbolted from the strut (two bolts with nuts). If it doesn’t fall apart, it will readily come loose with a small prybar or big screwdriver. That’s the only disassembly of the knuckle required on this vehicle. No messing with ball joints, no pickle fork needed. I grant that it’s a tougher job on some other cars, and your cautions may well apply to them.
The joints are not going to be separated because the thing to do is replace the whole axle assembly. A reman axle is cheaper than one new joint, and includes both joints (reconditioned) with new boots. Less parts cost and less work than actually replacing a joint - win/win. There is variation in quality of reman axles - I’d go with a reputable company like Carquest rather than a place that caters to do-it-yourselfers and purports to have the best prices.
Here, “fixed” means stationary in terms of in/out movement, not permanently attached or welded. It’s in contrast to “plunge” joints, which allow in and out movement so the axle length can change in accord with suspension movements. The most common set-up uses a tripod plunge joint for the inner and a Rzeppa fixed joint for the outer, but as you have found there are variations on this.
I’m going to agree with Gary here, since I’m the average driveway mechanic and I’ve done it. Buying a rebuilt axle is pretty cheap, and I wouldn’t want to tear apart the joint. That would be too tricky for my experience level. But just replacing the axle was pretty easy. The Haynes manual was absolutely invaluable because they use a lot of pictures, where the Chilton manual just explains it. For a job like that, I’ll take the pictures.
But I don’t think I have ever been so dirty. Wear clothes that you will throw away. Don’t even consider doing it naked to avoid that clothing cost. 
You have to scrub to get your skin clean. And the smell of axle grease is one that doesn’t leave your sinus’ for a long time.
The one I replaced was on an 89 Corolla, so maybe those are easier. Gary or Rick?
Don’t know offhand, but few if any are easier than on this Sentra.
And yeah, if the outer boot has spewed grease all around, it’s godawful mess.
I agree as a fellow average driveway mechanic and have replaced the half shafts on a 90 Plymouth Sundance and a 91 Honda CRX. It’s a full day’s work if you’ve never done one before, but it will save you money. Go with good parts as GaryT suggested. The remanufactured half shaft I put on the Sundance failed within two years (Autozone part).
Good luck if you decide to do it!
The big nut on the end of the axle has more torque on it than you ever thought possible. To loosen it, one person sits in the car with his foot firmly on the brake, and the other gets a monstrous cheater bar and a good stout socket, and pulls like an SOB. Same process to tighten it afterward.