(EDIT: republish for UK) Instead, it's the job that you have to do if for any reason you have an Olde Stile Jaguar rear axle setup that you have out of the car for the first time ever. As this setup hasn't been made new since the early 90s, it's just good practice. This post also covers the Powr-Lok LSD plates.
Technical specs in this post are limited, because they're not that hard to find - with one big exception. What does seem to be limited elsewhere are the tips and tricks, and actual photos of parts. Some of mine aren't so good, but they're a starting point. I couldn't make sense of the printed breakdowns until I had the parts in my hands, so you may be the same way.
Why would you have one of these? Well, if you have a Jaguar that has one, all excuses can be fended off with "I have a Jaaaaag". If not, you may be a hot-rodder revisiting something which is... well, pretty great, really. It's cheap. It handles a good bit of power. It's easy to mount. It uses parts that are readily available and can be regeared. It's also very heavy, which isn't a plus so much, but IRS systems generally are. Anyway, this isn't a sales pitch, it's an explanation of *what* you have to do if you've already figured out *why*. In my case, I bought one for my Ranchero:
A week ago, I finished the disorderly process of disassembling the main part of it, out of the support girder. Tobacco-chewing old-school hot rodders at this point will throw the girder away completely in favor of being able to work on the axle - bolting the diff straight to the frame. I'm not, but some people do. Anyway, that process leaves a pile of ugly, filthy (mostly filthy) parts - lower control arms, pins, axles, the center diff unit, hob carriers, spring-shock units... you get the picture. This picture:
All those pieces are the ones I'm *not* going to show you anything with. The only seals involved in them are a set of 16 O-rings (8 small, 8 large) that are used as seals on the inside of the control arm. They come loose to get the axle to this point (out of the cage), and aren't that confusing. In this picture from erareplicas.com, they are "7" and "8" - a washer goes against their face, a washer centers them, and the inside of that arrangement faces the control arm.
No real reason either to replace these or not - they're O-rings that hold grease (and no forces), so unless they're dead, you don't need to. OTOH, they're cheap. Very cheap.
They're also next to roller bearings that have no adjustment you can eff up. THIS IS THE ONLY TIME THAT IS TRUE.
Back to the meat and potatoes of the thing, you will have three large lumps in front of you that Contain Spinning Things. These have seals that you really ought to replace. If you aren't replacing them, why did you take it apart in the first place, you juggins? These three lumps are a large lumpy iron one and a pair of aluminum ones - the gear carrier and the hub carrier. We'll start with the latter pair:
(Xks.com) Unlike some of the other parts in the setup, these are mostly the same until the whole design changes in the late 80s.It's possible at this point your axles are still attached, and if so, good luck. You need them out first, and that may require FIRE.
The axles will come out best if you heat the hub face and put blocks behind it, then use a serious hydraulic press... if they don't just fall apart. That is also possible - I had one of each. This is not shown at all. When they're removed, there is a brass shim ring on each side, on the axle splined chunk. Do not, NOT, mix these up. Unless you like surprise bearing failure, then hey.
On to the seals, the "easy" ones are the ones in the control arm. Going back to the first exploded view, these are part "12". They're just a ring of felt, into which a sleeve of some kind(depending on model) goes, then there are shims, then... let's just look:
The XKS (what I'm tearing down) is set up as you see. Some other models have the puck at the very top made of multiple pieces or something, but this is what I have. Then there's the felt seal and the steel ring it sits in, then a BEARING SHIM, then a bearing, then another BEARING SHIM (SMALL), then a tube. It's important to keep the overall setup ID'ed to the right side, but not so much which shim goes where. Why? Because the tube+inner shims are a fixed length to a set of bearings, and the outside dimension (using the outer shims) is a fixed length, and putting this or that shim on this or that end will have no effect other than maybe moving the carrier back on the control arm .005" or so. Meaningless. To pull this stuff out, a 90 degree pick can be nice. The bearings probably will not need replacing, so repack/etc. when the time comes. There are probably specs for how tight that I'm not listing here, I haven't really needed to go looking yet.
On to the wheel/hub seals:
These hate you. With the axle out, there is nothing preventing the drive flange from coming out of the carrier, except the friction on the inner bearing. This can be a good bit. Once you pull the inner seal with any seal tool, you need to tap (or press, if your press can be set up well for this - mine wasn't) the flange out of the carrier, and the carrier is not designed to be gripped in any way. The best way would probably be to cut wooden blocks with notches for the carrier webs, but I wasn't patient enough for that. Despite the promise of the British Leyland curse (you can see the star-L on these castings), they came apart alright.
Next may be your first bit of luck. The outer seal is easy to access and is larger than the bearings, so you can just pull it out whenever - unless the seal surface (a replaceable steel ring) is done for, because it's behind the outer bearing and there's not a good way to pull that off other than... screwdrivers, maybe? Replace parts as needed, reassemble, and don't worry about the pre-load until the whole thing is going back together with axle shafts, because they set it (that shim). If you're like me, you are getting the axle shafts shortened, so that will be a while. When it's all together, I think you measure float in the bearings to .001-.010" with a dial gauge, but I could be remembering that wrong. Reduce the shim/etc. as needed.
Getting back to the case via a shitty picture, the stub axles have to come out. This is after the brakes have been taken off, as a note - no getting around that. On the right and left, there are bearing thingys that attach to the housing with five bolts - pull them, and with some gentle tapping they will come off. If they have three bolts instead, you should off yourself, because you have a special version of the case that Jaguar pretends doesn't exist and is harder to get parts for.
First things first, you have to pull a hub nut off, then press (yes, press if needed) the little baby stub axle out of its bearing carrier. The reason why is that the outer bearing is most likely sticking to the shaft a bit even if the inner one isn't. If it has all fallen apart by this point and only has a single bearing instead of two tapered rollers, then you're working on an E-type or 420 or similar. WTF, man. Get that thing to a specialist. Anyway, you're not so lucky here as with the hub carrier - the seal is behind the outer bearing. Assuming that the outer bearing didn't want to leave the shaft in peace, you now have a hideously distorted and torn up seal behind the outer bearing. You need the outer bearing off, and you're probably going to need one of these to do it.
Above the outer bearing is an additional reason the bearing probably won't let go - the crush sleeve that determines the bearing pre-load. Don't mix up the sides, yada yada. Once both are off, the seal can come out. To replace it with the new one, you'd put the new one into the Bearing Thingy with some oil on the lip, reassemble in the same order as things came out. Then tighten things hand-tight, and measure how hard it is to turn the shaft either with an in-lb wrench or with a dial gauge and a string wrapped around the shaft corrected for the right radius (recommended for some Land-Rover stuff, true story). IIRC, *that measurement* needs to increase by 6-10 in-lb when tight, and the torque spec for that nut is... around here somewhere. It's easier to find than a socket that will work with that nut, that I can tell you. Tight enough to achieve pre-load is more than enough. In all likelihood, your diff will be tight enough in fit and bearing condition if you're using your old bearings that the existing crush sleeve will not need serious abuse.
There is one final seal - it is the pinion seal. It's much like any other pinion seal and also has a crush sleeve. Measure current pre-load... here, I'll let erareplicas take this one. Past doing seals, there's one other rebuild item more likely than bearings to need attention, and it's the clutch pack. If, that is, you are a member of the Powr-Lok Master Race:
Ignore the 240D head in the background. To get the carrier out of the rear case requires cajoling and pleading, as the bearings are tight left and right - they have to be. Older styles which use the stubs on the sides to affect these would fall apart easy, this kind not so much. Spicer actually recommends the use of a spreader for the housing. There's a shim under each of the bearings here that makes the whole setup the right pre-load and aligned properly left to right - depending on wear, you might have discovered these need attention or not. The easy way being to see what the tooth engagement is like, float, etc. See the manual. If these don't need attention, don't monkey with them. You don't have to. Eight bolts away, the whole can of steel vegetables comes apart:
I marked the two halves before dis-assembly, but that strictly speaking probably isn't necessary. The center spider-gear tree has two sets of cams that it rides on (v-notches) that need to be 90 degrees out from one another, and that's all. Match angles to angles going together and you'll be fine.
When you've got it apart to this stage, you will have two stacks of *stuff*. In order from the carrier to the gear there will be a spring plate, a steel interlock plate, a friction plate, another interlock plate, and a friction plate. Or, if you have my unit, some of them are out of order:
The plate nearest to view is the spring plate, which in this setup is backwards from typical. The reasons for different arrangements are covered in the manual - this is the way it would be set up in a Jeep front axle. Less aggressive locking, more slip allowed on fewer friction surfaces. Oddly enough, on some cars this probably *wouldn't* mean the unit is lasting longer, even with only one side of the plates wearing, because if the clutches are slipping more before the tires are, wear must still happen.
In my case, it did. I could not find this information anywhere on the web, but the plate thicknesses for a new kit are ~.090" per plate, both friction and interlock. In the case of my plates, the plates are of a type that are *all* friction material rather than a plating, so it's harder to tell when they're worn out, but the thicknesses total is well below 5x .090". It seems to be replacement time, even with everything else in the diff being pretty low wear.
Reassemble with new in whatever arrangement suits (more, less locking), and those about to lock salute you.
(Lead photo from Wikimedia Commons, as attributed there - all other photos if un-cited are mine, but can be used in any way needed)