Hi Mac

Refurbing the IRS Cage is one of my Favorite Jobs on the Car, as when that job is done and dusted, it looks and feels Amazing in Terms of Achievement, as there are many out there who wouldn't want to touch that job with a Barge Pole, because it looks kind of impossible for a DIY person to do

Which made me want to do it even more!

Having said that for most people, doing it once is enough, so if you have any doubts about that Seal, then there may not be a better time to do that job than now, as if you have to go back to do it at sometime in the future, it will really hack you off

I've never had to do that Seal on my Car, as there is no trace of any leaking oil but if there had been then I would have done it there and then but as we cannot see how bad it either is or isn't, only you can decide, unless you ask a 'Shop' for a Second oppinion

 

Just to give everyone an update.

Last weekend I had the first chance to put the XJS on the Quickjack and take a look at the diff and to figure out what "belt and suspender" safety backups to the Quickjack can be setup. As mentioned above, it's a bit tricky to fit the Quickjack without it interfering with Radius Arms, but I think if I lift the car with the Quickjack and put ramp/wheel crips under the four tires and lower the car to the ramps, it will be high enough to undo the Radius Arms, and once free they should not interfere with lifting or lowering the car with the Quickjack.

I was reviewing the XJS ROM section on removing the IRS and noticed two errors or perhaps omissions. It doesn't say anything about removing the Speed Sensor, and it doesn't mention removing the prop shaft flange bolts. Though it does list the torque spec for the flange bolt (37-47nm), which seems low given how others have mentioned how hard they are to remove.

I've ordered all my parts, and I'm getting ready to get stuck in. Today, I'm going to lift the car and start doing some prep work, like disconnect the handbrake cable, spray penetrating oil on nuts and boIts that will have to come out, and see what else I have time for. I have some additional questions:

1. Does anyone know the measurement of the overall height of IRS unit? (to determine whether I'm going to pull it out back or from the side)

2. I seem to remember that there is an access door in the trunk to be able to unbolt the speed sensor, is my memory correct or is that wishful thinking?

3. Upon inspection, the diff looks like it is leaking out of the driver side output shaft. The brake disc on that side has quite a coating of Jaguar rustproofing (diff oil). How do I replace that seal?

[edit] 4. After loosing the exhaust coupling It appears that it will be easier to leave the exhaust hanging loose in the cage, then maneuver the pipes out of the cage once it is out of the car. It looks like that was done in OB's thread. Is that everyone else's experience? If one had a full size lift, I imagine the car can be raised enough to wiggle the pipes out of the cage, but not with what I have.

Thanks all for your help!

 

Radius Arms! What a day. I'd been soaking the cup/arm with PB Blaster for a couple of nights. Tried the roller wedge pry bar on the passenger side, and one knock of a hammer it popped free, and I foolishly had thoughts of posting how well that method worked. Driver side, haha, not so fast my friend. I tried every method I could find from searching the forum. Greg In France's cold chisel and hammer, Doug's 3 foot pry par, JagBoi and Motorman's air hammer, even a 6 foot long steel construction/digging bar. Finally, resorted to heat, and was taking pains to direct a pencil flame to the interior of the metal bushing and avoid the rubber part, but heat started to make the rubber smoke and I backed off. In frustration, I gave it another whack and it broke free! So heat works, but it's risky.

I actually bent the rolling wedge pry bar trying (see photo)...

I would still really appreciate answers to my questions, and I am sure I'll have more. Thanks

 

Well done Mac. Plenty of copper grease on the cup and the chassis projection when you replace it!

 

A couple of things I noticed while was working on the Radius Arms. Another detail missing from ROM is it looks like the ABS speed sensors need to be disconnected before dropping the cage.

Also, it looks like the speedometer sensor cable has enough slack that the sensor can be unbolted from the diff once it is lowered a bit.

Only one of the radius arm bolts had a safety wire, and even that one the safety wire was just threaded through to head and connected to itself so it didn't do anything. From searching it sounds like the safety wire is not necessary with use of thread locker like Loctite. Should I use blue or red thread locker?

 

Hi Mac

You don't unbolt the Speedo from the Diff, not unless you absolutely have to like for instance replacing a Broken Cable (Otherwise Don't Do it!)

Disconnect the Speedo Plug (which has a White Speedo Wire) from inside the Boot/Trunk then feed it through the Hole with the Rubber Grommet and also push the Grommet right through, so the Hole is Big enough for the Plug to also go through

Then Coil the Wire up underneath the Car and then Secure it inside the Cage with a Zip Tie



Undoing The Speedo Cable

Also undo the Wheel Speed Sensors (just one small Bolt in each Hub) then Carefully jiggle them out

You could have got those Trailing Arms off dead easy!

All you needed was a Slide Hammer, that you could have easily made from that 'Spike Thingy' you bent by putting a Weight on the Shaft, something heavy like an Old Hammer Head, with a Big Washer underneath and then Clamp the 'Spike' with Mole Wrenches

As long as it holds for a couple of Moderate downward Clumps, those Trailing Arms would have come off those Pegs dead easy, even without Oiling them first (although Oil always helps)



You were almost there with making a Slide Hammer, all you needed was a Weight and some Mole Wrenches at the Bottom, which should have held up long enough to give it a couple of Moderate Clumps to get those Two Trailing Arms off

When you disconnect the Hand Brake don't disconnect it from inside the Car or even Slacken it off

Just have the Hand Brake in the OFF Position, then make my Handbrake Cable Wrangler out of a Piece of Flat Strip with a Slot Cut in it and then using the Hand Brake Wrangler as a Lever, Just lever the Metal Blob on the end of the Hand Brake Cable Forward and then you can disconnect the Cable in 2 Mins!

Otherwise you could be there ALL DAY! (Ask me how I know!) or rather don't!



Hand Brake Cable Wrangler Hand Brake Cable Wrangler

No disrespect intended but that Jack Device is not what I would have used to do this job, as any Sudden Transfer of Weight, like for instance undoing the diff or even dropping the Cage, could make the Car nose heavy and disconnect the Cross Braces that lock it in position

And that could bring the whole lot Crashing Down with you underneath!

Same thing when you are dropping the Cage, as the Diff (Can and usually does) Pitch Forward enough to de-stabilize the Car or even Clip one Side as you lower it down

Any Sudden or unexpected movement, that you would not be able to Control and it would be Game over!

Have a look on YouTube and then see what happens when they Fail and while they could be just the thing for doing normal Stuff around your Car, I really don't think that dropping the Cage on a Two Ton Jag is really what they were intended for

So I would take a Hit and Sell them and get a Scissor Lift about $1500-$2000 or else make sure you've got 911 on your Speed Dial!

 

Mac,

Great suggestions from OB!

With my slim fingers and perseverance, I can remove the speed sensor from the diff with everything in situ. I had to do it to change the shims after my diff was rebuilt and the speedo was fluctuating.

BUT...if I was removing the cage again, I would disconnect the wiring from above as OB has described, and then remove the sensor once the cage is out if you're rebuilding the diff. Count the shims and keep them safe.

Cheers

Paul

 

Thanks OB, I appreciate your experience and advise. Always willing to learn something, but I have some questions regarding your post.

I must be missing something so apologies, but undoing the two small bolts holding the sensor after the cage is lowered a bit seems less of hassle then tearing apart the trunk and unplugging the sensor. Your "Don't Do it!" has me certain I'm missing something, what is it?

Apologies for leaving you off the list of everything I tried, but I did use your method and it didn't work. I even added some weight to the slide hammer, but no joy.


I genuinely appreciate the concern, but a few points. One, I don't want a Scissor Lift as it doesn't suit the many purposes I intended when I got the QuickJack and I don't have room to store it. Two, I wasn't kidding about belt and suspenders, I don't ever go under any car with a single support. I don't fully trust jacks, jack stands, cribs, ramps, or lifts. There always has to be backup support. Additionally, I believe I've seen every youtube video of a QuickJack failure, and every video was user error or stupidity. Such as forgetting to unlock both sides, not bleeding the system properly so the two units don't lift or lower in tandem, etc. The one possible exception was both user error and doing something that QuickJack says you can do, but I think is dangerous. They say you can stack the rubber blocks (but I never would) and the guy was lifting a heavy truck on his driveway. However, the driveway had a slope exceeding what QuickJack specifies so the stacked blocks and the slope were a disaster waiting to happen.

Your comment on the car suddenly being front heavy is well taken, and I was concerned about that as well. However, my plan was NOT to raise the car to full height, and then lower the cage. I am planning to have the car at close to normal ride height, with the ATV/Motorcycle jack under the diff/cage to support, then to raise the car prior to lowering cage. That way if there was a nose dive, it would be with the front tires inches off the ground. That's the advantage of a lift or QuickJack for this job, since the cage is so heavy, lowering it the minimum amount seems wise. I'm also building a platform to mount to the ATV jack with raised pads for the appropriate lifting points on the Tie Plate, and for the front of the diff to prevent it from rolling forward.

The nose dive concern is maybe overwrought. A standard shop two post lift uses the same four jacking points that the QuickJack uses, and the same jacking points most use for jack stands. I've never heard of XJS falling forward after a cage drop from a two post shop lift, and the physics would be identical. Nevertheless, one of the backup supports is to have a floor jack positioned under the front crossmember just in case.

Has anyone heard of an XJS falling forward when supported by the four jack points on level concrete? Given the weight of the V12 beast, it isn't out of the realm of possibilities, but I would think the ROM would have taken that into consideration.

 

Paul, you just triggered a memory. Probably 15 years ago my speedo would intermittently either stop or show higher speed and I replaced the sensor, so I must have done it in situ since I've never dropped the cage. I don't recall shims, but it was a while ago.

 

Hi Mac

The reason for taking the Cable of the Speedo out of the Car, rather than unbolt it from the Diff is that doing it that way, you don't disturb the Shims or even risk losing one of them in the process

Because the Last thing you want is to have the Car all back together and then find the Speedo isn't working

As for the Two Post 'Shop Lift' that is Bolted into the Floor, so even if it is subjected to uneven weight, it won't be falling over anytime soon and with a Two Post 'Shop Lift' you've also got the Advantage of being able to undo most of the Bolts at a Comfortable Height

Then Lower the Cage right down to the Ground, then undo the last few Bolts and then once having done so, lift the Car up in the Air while leaving the Cage either on the Ground, or on a skid where it can be wheeled away to be dismantled and rebuilt

You can also get Scissor Lifts, that can be left underneath the Car, with the Lifting Arms folded back, so the Car can drive over the Scissor Lift for easy Storage

Also I cannot imagine that Jaguar could ever foresee a Time that a DIY Motorist would ever Consider something like Dropping the IRS Cage themselves rather than have this done by a 'Shop' or Main Dealer as maybe they could not also Foresee, the XJS still on the road some 30 Years Later

Though in any event whatever way you decide to go, it always pays to be prepared for the unexpected, which I'm sure may have happened to all of us at one time or another

Good Luck with your project

Alex

 

With the QuickJack in its higher locked position, I have 23"/58.4cm of clearance out the back of the car. My best eyeballing it looks like it's 18"/45.7cm from the top of the cage down to grease nipples below the hubs, and about 14"/35.5cm from the top of the cage down to the bottom of the tie plate. My ATV jack has a minimum height of 3"/7.6cm. So with the tie plate on the jack and with it raised enough to keep the nipples/hubs off the ground that should be about 20" and I should have 3" to spare. Does that sound right?

Do people remove the grease nipples just in case they might get dinged?

Thanks

 

Yes, remove the grease nipples on the bottom of the hubs.

 

Hi Mac

One of the things you might need to get under the Car for is to tie up the long exhaust pipes, so the Weight doesn't crack the Manifold when you disconnect them and you also need to disconnect or Cut through the Rear Flexy Brake Pipe and also best to renew this while its off

Hard to visualize what you are doing without seeing photos but when you take the Wheels off if you haven't done so already, then the Springs in the Cage are going to drop the 'Wishbones' down even lower (not to be confused with Trailing Arms that you have already disconnected)

This could also have the effect of making the Diff fall forward and maybe Clump the underside of the Car like a wrecking ball (though hopefully not)

Any sudden or unexpected movement like that could destabilize those Quick Jacks, so you need to be really careful that this doesn't happen

Also when the 'Wishbones' drop down aided by the Cage Springs, then you could have a lot less height than you were hoping for

 

Thanks OB, I've already used steel wire to attach the exhaust to the transmission mount thanks to finding it mentioned by Greg In France in another thread.

Those measurements were taken with the wheels off and car in air so I think that the wishbones would be fully extended.

 

Best laid plans and all that.

Yesterday was the day I was planning to drop the cage, but as I was driving my Range Rover home Friday evening I detected a bit of a bearing noise. Since it is my daily driver, and I need it for upcoming road trip it has moved up in line for attention. Fortunately, with the cage still in and wheels back on, the XJS was movable to make space in the garage for the more pressing work. Next two weekends are spoken for, so it looks the drop date will be in three weeks. Will update as I progress.

Thanks everyone!

 

I forgot to mention one annoying detail. Remember I mentioned in the first post I had a fuel leak around the IRS? It has magically healed itself (temporarily one would assume). So once I drop the IRS, It won't be obvious where the leak is located. Ugh.

I'm trying to figure out how the leak could stop on it's own, my only guess so far is that the warmer temps soften and expanded the rubber hose. Weird right?

 

QUICK QUESTION -- Would it be a good idea to remove the 6 bolts on the tie plate that connect it to the cage while access is easy? IOW, before the ATV jack is in place on the tie plate? Once it is on the ATV lift and the IRS is out of the car, it might not be easy to access all those 6 bolts.

Or dumb idea? Hopefully some can answer soon as I'm working on it right now.

Thanks!

EDIT: I decided it was dumb idea. With a slight modification to ATV jack, access to those bolts shouldn't be an issue once the cage is out.

 

If you are stripping it then it won't make much difference - you are going to need to find a way to man handle it anyway as pretty much all of it comes out the bottom - but the diff bolts in from the top there's no way you are doing this bottom down - it is far better to do them bottom up, in fact placing it between two saw horses upside down on rubber non slip pads may be a better option because you can get to the diff bolts and gravity will be working in your favour during re-assembly.

 

@BenKenobi Thanks. Since I have to get to the output shaft seal, and I'm going to replace discs and calibers, I assumed I would need to remove the cage to get easy access to everything. Or is that a bad assumption?

 

Can be done in the car but not worth the hassle unless you have a nice two post lift and even then it is a hassle - get it on the bench, pretty sure I read that you have a Salisbury diff - don't waste your time if you have a Dana (no drain plug, the seals and stuff to put a Dana back together are unobtanium unless you drop really lucky. Problem with the seals is that the discs cook them if the cars driver is a brake lover but they also harden over time.