I'm still working on my XJ8 LS swap project. No recent posts on that thread lately because chasing down issue with the LS motor. Cranks and fires a couple times but doesn't run. Might be spark or injection issue. Possibly bad ECU. 57loboy and I talk frequently. Looks like he is leaving me in the dust. Congrats to him if he's on the road first.
Issue addressing in this post involves the rear end.
Have one bad wheel bearing and need to replace the donuts on XJ8. I've done the donuts on my daily driver XJ8 before via the one side at a time method detailed on the forum. I have my XJR parts car. 105k miles on the XJR and 142k miles on the XJ8. XJR completly stripped except for steering rack, gas tank, doors, boot lid and rear end. Instead of replacing the bad wheel bearing on the XJ8 considering removing the wheel assembly and one half shaft and replacing with one from XJR. Another option into to replace the entire rear end.
Question is how hard is it to switch the entire rear assembly. Manual only shows removal of diff leaving half shafts and wheel assemblies in the car. Since I also have to do both donuts seems like less time. Advantages would be already have other diff out if one went bad and could haul off XJR to junk yard.

 

Jaguar warranty time for REMOVE REAR SUSPENSION FOR ACCESS AND INSTALL is 1.9 hours.

A real world estimate would be closer to 3 hours.

I used to charge 10 hours to replace the diff bearings in the XJ40 or X300. (same suspension)
The diff bearings (pinion) were notorious for failure in the XJ40 and X300.

 

I'm always stunned at the book time. But, they are on the easier side of major jobs - I can see the logic in switching the rear ends, maybe make up a nice one out of the two with brakes and A frame you can also do a fluid change and fit a new breather, if it needs a seal, it's another simple job on the floor. Not sure if there's a major suspension difference?

https://www.jaguarforums.com/forum/x...8/#post2224646

Some good pics^
.

 

Technically, it is NOT BOOK TIME but WARRANTY TIME that Jaguar will pay the dealer for labor time.
Chilton, Motor and AllData post LABOR TIME GUIDES that are the 'real-world' time guide averages.

Manufacturers are notoriously 'stingy' with labor payments to dealerships.

I don't have access to the industry time guides but I do have the JAGUAR 'REPAIR TIME SEARCH' program that we used at the dealer in the late 1990s/2000s.

 

Thanks @motorcarman and @Sean B . Question. Do I have to release each spring separately like when replacing one donut at a time or can I put a floor jack under the A support, unbolt and lower? Compressed springs scare me. Would appreciate the steps you would do.

 

I never compress the springs to replace spring isolators. I lower the arms to release spring pressure.

You can slowly lower the suspension and the dampers will keep the springs in place if you remove the 4 upper fasteners of the 'spring-hat' from the body.(leave the top nut on the damper)
Leave the springs slightly compressed and move the entire suspension to the other car.
Bolt the 'spring-hats' to the body and finish lifting the suspension in place.

 

Seems like it would be easier to drop the rear end and swap the diff there than it would in situ. Dropping the assembly complete isn't too bad, just take the exhaust out first. With how nestled the diff is in the rear subframe you're basically taking the whole thing apart anyway, and then you're not trying to hold a hundred pounds of steel over your head. I just did this recently for a diff swap and servicing control arm bushings and pivot bearings.

You can (and should) also leave the spring assemblies "assembled" to the lower control arms like motorcarman said, and if you don't need to do any service on those just leave them as is. If you want to decompress the spring in situ to replace the foam bits, there's a nice trick that can be done by lowering the a frame and compressing the lca, then undo the shock bolt and lower steadily that way...

 

you can easily beat warranty time even without a rack. get some hustle in there

20 minutes down 25 minutes up if you get the exhaust off the hangers

 

Thanks. You four always give good advice. Just noticed motorcarman's post count. 11,775! That has to be the record. After I get the XJ8LS on the road, I plan on doing a Jag modification I don't think anyone on the forum has done. Plan on taking gas tank out of the XJR. Something else to sell on eBay. After that going to take a sawzall and remove the trunk to make a trunk sofa. I have the back seat that I swapped out for the one from the XJR. Don't think the wife will let me put it in the living room so probably will be in the garage.

 

One more question. The Jag workshop says discard the subframe bolts and replace with new. Guessing not torque to yield. Is that necessary?

 

Talking about the bolts that go through the big circular bushes in the a-frame into the main chassis (and the related bracket bolts)? I've reused them, just being sure to apply adequate loctite 243 or 263 where necessary (so all those bolts I mentioned, and the bolts that mount the rear truss to the main chassis).

This reminds me of one other thing - the nuts that secure the long pivot bolts on the inside axis of the lower control arms (the foot long bolts close to the diff) - if you are removing them, DO NOT zip that nut off (or back on) with an impact. You WILL gall those threads and trash your very hard to find pivot bolt. Ask me how I know.

 

I have an impact wrench. Only thing I ever use it for is taking off lug nuts and putting back on loosely. When I first changed pads on my daily driver some idiot had tighted a few lug nuts so much I bent the Jag supplied lug nut wrench. Had to remove with a extra large breaker bar by standing on it. I'm 220 and probably stood on it 2 feet out.