ZJ CV axleshafts swap

[DirtyComanche]

On my MJ with an 87 XJ front D30 (first generation unit bearings) I swapped to the ZJ CV shafts. This is in my build thread too, but nobody reads those.

Business end of a 260x shaft vs a CV shaft:
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I'd been told that the ZJ CV shafts were a bolt in swap. I'm guessing they might be for a later XJ, or an ABS equipped XJ. Using my early non-ABS unit bearings they are not. The tone ring, far left, had to be removed for the shaft to actually fit with the unit bearing. However, this left an issues, as there is a seal on the inner side of the unit bearing, which normally rides on the runner, far right, pictured as removed from the OEM 260x shaft. However, the machined surface that the tone ring is pressed onto on the ZJ shaft is a smaller diameter than the surface for the seal runner on the OEM shaft, so you can not just install the seal runner on the ZJ shaft. As it was I felt I needed to just get it put back together and installed it with the seal not running on anything, I packed the bearing face with grease to protect it for now.

The debate (to me) is if the seal is actually needed, as IMHO it is a holdover from the original hub design which did not use sealed bearings. However, needed or not, it would help to protect the bearing from water/dirt.

If I have to I believe I could center punch the mating surface on the CV shafts, then put the seal runner on with a little RTV or Loctite retaining compound, as it is maybe only 15 or 20 thou different in diameter (calibrated eyeball).

I'm supposing this issue also could be that the CV shafts I bought are built goofy (they are A-1 Cardone), or perhaps the seal runner from a later 297x/760x shaft is the correct dimensions.

 

Looking at unit bearings on Rockauto leads me to believe I am okay, as the major visual difference between the early (to 89) and later (90+) unit bearing is that they deleted the seal which would mate with the runner on the axleshaft.  I did not check to see if later axleshafts even have a seal runner on them, or if it would be a different part number.

Anyone able to shed any light on this?  Would rather not tear it apart to bojang the wrong seal runners onto it, but I don't want to destroy an expensive set of brand new unit bearings.

[Keyav8r]

As an old machinist I can't recommend the center punch and RTV method. Generally doesn't work well or long, specially with thin wall parts. Look into Speedi-Sleeves first. They are thin wall sleeves that are used to repair worn seal surfaces. There may be a size (or possibly two sizes) that would fill that space under the seal runner. You'll need to use micrometers or good digital calipers to check the shaft OD and the seal runner ID to determine if there is a Speedi-Sleeve that will work for you. They may be sold under a different name in the frozen North (as we "Alabamians" think of Canada) but you should be able to find them at an industrial bearing supply house or on the internet.

[MeanLemons]

Are you able to use newer hubs?

[DirtyComanche]

As an old machinist I can't recommend the center punch and RTV method. Generally doesn't work well or long, specially with thin wall parts. Look into Speedi-Sleeves first. They are thin wall sleeves that are used to repair worn seal surfaces. There may be a size (or possibly two sizes) that would fill that space under the seal runner. You'll need to use micrometers or good digital calipers to check the shaft OD and the seal runner ID to determine if there is a Speedi-Sleeve that will work for you. They may be sold under a different name in the frozen North (as we "Alabamians" think of Canada) but you should be able to find them at an industrial bearing supply house or on the internet.

 

The retaining compound definitely works better than RTV, RTV would be the last resort.  I have other adhesives in my tickle trunk that would probably get it done without any issues, but that's beside the point, it would be a hack repair at best.  The real question is if I need to even worry about it.

 

A speedi-sleeve is a speedi-sleeve.  I get the same CR/SKF/FAG/TImken/National/Whatever stuff as anyone else, it's just a lot harder to get oddball pieces.  I'd bet if there is one available that would do it that I'd be $300-400 Canadian Pesos into it, at which point I'd put the good money to better use and buy different shafts.

[DirtyComanche]

Are you able to use newer hubs?

 

No idea, I think I'd need to change my knuckles and brakes, there's a difference there.  Eagle probably knows.  But it would be a waste if the only functional difference (for this issue at least) was that they deleted the seal and sealrunner that I'm having issues with.

[Hippie66]

Just curious why you'd want CV's instead of u-joints?

[DirtyComanche]

Just curious why you'd want CV's instead of u-joints?

 

The shafts that were in there were the weak 260x junk, and the ujoints were blown right up along with their being a good chance the ears were worn.  It would be good money after bad to change the ujoints in them.  I have no 297x/760x stuff around, I gave away all my D30 stuff years ago, so I'd have to junkyard or buy a new set of shafts.  The ZJ CVs have NOT been tested in any quantifiable manner, but there is plenty of guys running them in ZJ (and WJ, same but different) applications with 33" tires and a V8, so they are almost undoubtably stronger than the 260x setup, and I bet at steering lock they are still stronger than a standard 760x setup.  But most importantly they were in stock at my local parts place and for not a lot of money, which assuming I could just bolt them in and go made them a better deal than screwing around at the junkyard or waiting on a set of aftermarket shafts.

 

Truth be told, having run them, they are smooth.  This truck is NOT a hardcore wheeler, I think they're probably a good fit for somebody who is mostly on the street and is keeping to smaller tires and not super abusive use.

 

Unfortunately they turned out to be a little less bolt in than I had hoped.

[Hippie66]

Thanks, I can understand that. I prefer u-joints for easy trail fix. The only CV's I want offroad are on my VW Thing.

[DirtyComanche]

And at this point I think the only functional difference (for me) between the current style (sealed bearing) early unit hubs (to 89) and later (90 until they changed the brakes in 99 or 00, or whatever) is that they deleted the seal that I have an issue with.  But I still can't really confirm that as Renix stuff is now too old for most people to care about.

[DirtyComanche]

Thanks, I can understand that. I prefer u-joints for easy trail fix. The only CV's I want offroad are on my VW Thing.

 

These are cheap enough you could keep whole spares with you...  Which IMHO is the only way to go with ujoint shafts anyways, because if you really break the ujoint you will wreck the yokes.

 

I've been told that you can drive on these even if they're broken, but I'm sure it's like any other steer CV where it may lock up your steering if the wrong parts wind up wedged in the wrong places.

[gogmorgo]

I've got CV shafts as well in mine, got about 15,000 miles on them now I think. Surtracks I got off RockAuto as listed for r my MJ. I didn't even need to knock the tone rings off, they went in great, but then I've got the later bearings etc. on my '91. 

Why do I like the CV's? Well, for daily driver use, especially with my 242 you pretty much can't tell they're there in 4x4, none of that back-and-forth hopping you get with u-joints with some steering lock. Plus I've actually broken a couple u-joints on my MJ, but haven't managed to do so without also wrecking the yoke. And they have still taken some abuse with no complaints so far.

[Hippie66]

I used to keep spare drivers front axle and spare u-joints, as well as a spare driveshaft for my old XJ. I replaced u-joints in front axles several times. The key is stopping as soon as they break.

[DirtyComanche]

I've got CV shafts as well in mine, got about 15,000 miles on them now I think. Surtracks I got off RockAuto as listed for r my MJ. I didn't even need to knock the tone rings off, they went in great, but then I've got the later bearings etc. on my '91. 

Why do I like the CV's? Well, for daily driver use, especially with my 242 you pretty much can't tell they're there in 4x4, none of that back-and-forth hopping you get with u-joints with some steering lock. Plus I've actually broken a couple u-joints on my MJ, but haven't managed to do so without also wrecking the yoke. And they have still taken some abuse with no complaints so far.

 

It's unfortunate there isn't more 'hard' data on these things.  I could have bought CVs that would bolt in from Rockauto (they're for the NP228 setup or something), but the assumption was that they are not as strong as the ZJ/WJ setup.  I don't know about the HO era XJ/MJ CV shafts.

 

I really do like how they run, and I could tell you right now if I was building a truck to tear up the street I would use these with a NP242 and a pair of truetracs...  I bet you could hit the autocross and make jaws drop.

[gogmorgo]

I don't think there ever were factory XJ/MJ CV shafts. The CH8220 (left) and CH8221 (right) both list up to '93 for XJ and MJ, and '93-'98 ZJ as applications, so there's a good chance they are the ZJ shafts. Come to think of it the shafts I ran after I broke my first u-joint came out of a ZJ (and I think also had bigger u-joints... and the second one I broke was one of them IIRC). These were literally the cheapest new shafts I could source at the time (lucked out on a closeout sale), which was mostly why I got them.

 

As far as tearing up the Autocross, the XJ and MJ are disturbingly good for having two solid axles. Even with my open rear diff in 2wd I surprised a couple people, but that was back before the NP242 went in. I want eventually to get Trutracs or similar in mine. I'm a big fan of the Torsen T1, but it doesn't really exist any more, ad I don't think it ever did for the D30 and 8.25 which I'll be putting into the MJ once I've collected all the components. Probably going to leave the rear open for now cause my 8.25 already has 4.10's, but if I need a new carrier anyway to regear the 3.55 D30 I have sitting around... yeah. But that's a dream a long way off for now, more important things to waste spend money on.

[DirtyComanche]

The CV shafts I bought are an alternate P/N to the ones that you have.

 

There was factory CV shafts for early XJs with the NP228 or 229 or whatever it was.  Rare.  They were very small.  And not good at all.  There was a P/N on Rockauto for a CV shaft that fit 84-89, and I was concerned that it would be a direct clone of that early CV.  Thus I bought the ZJ ones.  As per the usual, more research might have answered some questions ahead of time about how the ZJ shafts would fit in a Renix era axle.

[shelbyluvv]

I have replaced the CVs in my WJ 8 times. They are total crap. I did it twice under warranty when it was only a year old. The 4.7 and 32" tires do not play well with CV joints.

 

I think you wasted money on them. I ended up going to u joints in my WJ.

[Crash]

I have replaced the CVs in my WJ 8 times. They are total crap. I did it twice under warranty when it was only a year old. The 4.7 and 32" tires do not play well with CV joints.

 

I think you wasted money on them. I ended up going to u joints in my WJ.

Did you get the IRO kit?

[shelbyluvv]

Nope, BDS

 

EDIT: Yes I used IRO for the shafts. I thought you meant the lift. I was busy digging up a septic tank and didn't really think about my reply.

[DirtyComanche]

I think you wasted money on them. I ended up going to u joints in my WJ.

 

It was buy them or completely waste money on replacing garbage 260x ujoints, or not be able to drive the truck.   If they blow up they blow up, I'll order something else if it happens.