Rear subframe rebuild, advice needed
 

Since it seems impossible to sell my XJS, I decided to keep working on it. Plan was to drop out the rear subrame to redo the brakes and shocks. So far one of the radius arm bolts have snapped off at the head, grease zerk on left hub broke and oh yeah, unbolted the prop shaft and got bathed in gear oil. Brakes are now the least of my worries as I def need to rebuild/reseal the rear end and also tap out the broken bolt. Where is the best place to get a rebuild kit or at least the seals for this? The car only has 67k miles on it so I assume the bearings will be in good order. Also, everything I read tells me that I should have a Dana rear in it but its got a drain plug and finned cover like the salisbury unit.
I'm trying to fall back in love with the car after walking away from it a few months ago but this is a rocky start to our new relationship.

Any advice and parts sources will be greatly appreciated.
Kevin 1988 XJS

Hi Kevin

Sometimes its best to 'bite the bullet' and not throw any more money at it, or you could very easily be spending enough money to buy a better XJS that is in good running order and in the event you have the room, keep the one that you have for a 'Parts Car'

Are you using impact to undo the radius arm bolts? I recently pulled a complete IRS from the junkyard and used a cordless Milwaukee impact that can do 1100 ft-lbs. Everything came out, not a single broken bolt, and the sills on this car were like swiss cheese they were so rusted.

You certainly should not have got gear oil out when you undid the driveshaft flange, that's unusual. Probably means the pinion seal is gone.

You can get parts at any of the usuals, such as SNG Barratt or Coventry West. It may be easiest to send the diff in for a rebuild to Coventry West? If you have a drain plug, you have a Sailsbury, assuming it had a flange at the driveshaft connection. I believe the Dana diff was a 3 ears.

I'm not aware of kits per se, for doing a whole IRS rebuild, but you can look at the parts diagrams and figure out what you need at Jaguar's Classic parts division: Steering and Suspension - Parts For XJS from (V)179737 to (V)226645 | Jaguar Classic Parts UK

You'll probably have to go through several section to find all of what you need. The differential is under the Transmission and driveline section.

If you need bearings those are commonly available at any industrial bearing house.

Drain plug = Salisbury.

Pinion seal is common, and not a major task.

The output shaft seals behind the rotors, bit of a task. Bearings are generally OK, you will need the seals and the collapsable spacer for each side. I would NOT do the cradle out without doing those seals, coz to do them a week later is not going to be fun.

https://cimg2.ibsrv.net/gimg/www.jag...072fe9c62d.jpg
Rear Calipers looking well done and basted in brake fluid

https://cimg3.ibsrv.net/gimg/www.jag...1725b1bb0c.jpg
Finally got it out with some muscle from a buddy after work. outer hubs also showing signs of leakage

https://cimg4.ibsrv.net/gimg/www.jag...bca45f5d71.jpg
Snapped bolt on front mount for radius arm bushing.

So it took 4 hours but I got it out of the car. Right side exhaust decided that it wasn't happy and snapped midway between cat and connection into subframe. The broken bolt was because of corrosion. I've never seen a bolt fail in a concave fashion before but the metal was very pitted and almost hollow. Will def be replacing all the seals on the diff itself. Decided against rebuilding the calipers myself and just going to order reman ones along with rotors and all pads. 4 shocks were waiting to be replaced anyhow. Only 1 of the 4 body mounts show signs of separation but im gonna go ahead and replace all 4. I've attached some photos. Also, the outer hubs have a lot of grime on the, how hard are these to "reseal"?

Well done.

Very good plan for rebuild.

Those outer hubs are only grease filled, and not filled in the true sense of that word, no oil at all, so any leakage there would be of no real concern to me.

Overgreasing the u/joints on the half shafts makes a horrible mess.

Clean it up, and dont over grease the u/joints etc, and it will stay dry.

Maybe the plug into the hub is leaking or not sealing? It looks a bit like the grease stains start there in the photo?


Greg

Yep,

A good days elbow grease involved in cleaning all that up.

That's not uncommon. The pinion seal may need replacing but that is not the cause of you having oil behind the uni. flange. Oil can migrate along the splines, l usually apply a smear of loctite master gasket to flange splines when doing the diff or to the face of the propshaft flange mating surfaces.

thanks for all the motivation and tips guys. I got the calipers off today and got 2 of the springs put onto new shocks. I am definitely going to do all the seals on the diff but was wondering if anyone had a good step by step for the disassembly. Also, I have no idea how they got safety wire on those caliper bolts so I was wondering if I could use hi temp loctite instead. Tomorrow I'll start cleaning the hubs but youre right Greg, the muck does start pretty high up, right around the plugs. Do they sell these or do I pull them and use RTV?
I'm using the new QuickJack garage lift I got for christmas and decided to set the car flat down while the back end was out. It makes accessing the middle of the engine super easy now. Here's a pic just for kicks

Here's one write-up on replacing the stub axle seals....which is contrary to the official method as it doesn't use new crush spacers
On replacing output shaft oil seal - XJ6 S3

Someone probably has a write-up on replacing the pinion seal....which is much easier. The service manual has the info, of course

But with both the stub axle seals and the pinion seals you are tampering with clearances so it is 100% essential to mark fasteners and return them to their exact torque and location on reassembly


Just went thru this. It's tricky getting in there to properly wire 'em up. I needed 3-4 attempts on each side to get a good result....and that's with the cage disassembled and everything out of the way!

Loctite is perfectly OK and a popular alternative


I always reuse the plugs and never had any particular problem with them leaking, personally....although some RTV couldn't hurt !


Cheers
DD

Might wanna check the fulcrum bearings on the lower wishbones while you're at it.

I'm just finishing a 'cage out' mini-overhaul myself. All the fulcrum bearings were in great shape except the RH outers...which were rusty and actually coming apart, #18 in the illustration below

Wishbones and Mounting-Rear - Parts For XJS from (V)139052 to (V)179736 | Jaguar Classic Parts UK.

I've replace these RH outers on a couple different Jags. They're more exposed to water splash-up. In countries where they drive on the left, I suspect the LH outers would take more water abuse. Just my theory...ha ha

The inners (#11 in the illustration) seldom fail, in my experience. My theory....I'm full of theories.... is that the leaky differentials always keep the bearings well oiled even if the owner doesn't.

Cheers
DD

Loctite is just fine.

I use it of the mounting bolts, top and side as well.

The weeping of grease from those tin caps is generally due to the hub being over greased.

Using my new QuickJack Lift that my wife and mom got me for Christmas. I couldn't help but drop it all the way down with the rear cage out. Wife walked out to see what I was doing and I had to sing " Loooowww Riiiider"

Forum won't let me insert photos anymore so I'm trying this method, hopefully you guys get to see this

Baxtor, I went back out and looked and I think you're spot on. The oil came from the between the 2 flanges yet the bottom of the diff where the pinion goes in is bone dry. Guess at this point, its all coming apart anyhow but will be marking all of the big nuts to return them to original position.. The car only has 67k on it so most of this leaking is a result of 28 yr old rubber sitting around....or so I would like to believe

All, I started cleaning things up and looking around and I noticed that the Pinion nut is not snug against the flange. I can see movement between the 2 when I rock it back and forth. normal? fixable? do I need a new crush ring? Assuming if I tighten it, I move the pinion further away from the ring gear thereby increasing backlash which is bad or do the shims maintain gear engagement and the crush sleeve just adjusts bearing preload?

It should be snug. That nut controls the preload on the pinion bearings. Unfortunately you have to go reasonably deep into the diff to get it right, but it is important to get it right. At least you have the suspension out and are doing brakes anyway, so that makes it much easier.

There is a shim between the case and the bearings to position the pinion in the case, and a crush sleeve controls the bearing preload. Assuming you bring the preload back to where it should be, the pinion will be properly positioned. With the nut loose though, the pinion is free to move further into mesh with the ring gear and have no backlash.

With just the pinion in the diff case, when the preload is correct the torque to turn the pinion with used bearings should be 20-25 inch-lbs (note that's not ft-lbs!). With new bearings the figure is 30-40 in-lbs. That is with the seal in place. Note that you might have to apply up to 130 ft-lbs to the pinion nut to achieve this figure. You have to do it in small stages and then check the drag, you can't back off the pinion nut if you over torque.

With the carrier / ring gear put in place and the bearing caps torqued (63-72 ft-lbs) and the backlash is checked (backlash should be 0.006"-0.010", minimum 0.006", but aim to the low side) and no output shafts, the torque to turn the pinion shaft should be an additional 10-20 in-lbs from what was recorded to turn the pinion alone.

In the manual, it says to use loctite on the splines between the flange and pinion shaft, so that should stop any oil from leaking.

Hey All, See photo below, got the rear end taken apart and found this. Do they sell just this spacer?
https://cimg3.ibsrv.net/gimg/www.jag...d3dab743c7.jpg

Took the rear end apart, found the spacer that fits between the bearing and the pinion yoke worn down quite a bit. Guessing this was a result of the pinion nut being loose and allowed to spin. Do they just sell that spacer?

Part number is JLM614. Shows as being available, costs £2.42 in the UK.