Re-assembly of IRS

I now cleaned and sourced new parts for re-building of the IRS and have a couple of questions for the more experienced.

When I took the half shafts and disks off, all of the spacers were between the differential output shaft and the brake disk. None between the disk and the inboard end of the half shafts. From my understanding, the rear camber is adjusted with shims between the half shaft and the disk. Should I move at least some of the shims out to the end of the half shaft?

I have read that the bleed hole in the hub carrier should be closed. The comments were that it just creates a mess with no useful purpose. Should I plug it up before I go ahead with the assembly?

Thanks for the assistance.

Jim

When I reassembled my IRS I first shimmed the rotors so they would be centered to the caliper then shimmed to adjust for camber. I ended up with shims on both side of the rotor.

To be clear all the big half shaft shims are between the rotor and the half shaft - none are inside the rotor, nor have they ever been as far as I know. Their presence there would completely destroy the position of the rotor to the caliper. Not sure if you are speaking of the bleed hole in the grease cap for the axle bearings , or the one for the shaft that holds the carrier to the lower control arm, but I’ve never heard of blocking either. You get some oily seep from them but it’s virtually negligible.

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Terry,
After my diff was rebuilt the rotors were visibly not centered with the calipers and required several shims to properly align. Its been nearly 8 years and several thousand miles with out problems…

Those shims go on the caliper brackets. They are “special”, but could be replaced by hardware store shims - maybe, as they are very thin. Since the factory shims are so thin it would be supposed they expected the rotors to be darn close in regular production. I have the Series I thin rotors, so later cars may be different.

I read Jim’s question as talking about the large shims for setting camber, not the caliper shims for centering the caliper over the rotor, although I can’t quite conceive how there were spacers between the output shaft and the disc.

Hello Terry,
I read Jim’s Post as he is referring to Spacers and Shims being the same thing and that there are only Spacers (Shims) between the Output Shafts and the Rotors (used to center the Rotor in the Caliper) and no Spacers (Shims) between the “inboard end of the half shafts” and the Rotors (used to adjust Camber).

Hello Jim,
If the Rotors are centered in the Caliper, simply carry out the procedure to set the correct Camber.

Regards,

Bill

Thanks guys. I know that there are shims for the calipers which is why the placement of the large shims between the disk and the output shaft seemed strange. I will do any adjustments needed to centre the calipers with the shims and move the other larger shims (spacers) out to the outboard side of the disk.

On the other question, there may only be a small amount of leakage from the hold in the carrier but does it serve any useful role?

Thanks
Jim

Hi Bill - a bit off topic. A few threads ago you mentioned that you made spacers for the front wheel bearings to enable preload be done properly. If I read that correctly could you send me some details at: moledor@telus.net

Terry

Understood but I needed to move the caliper towards the pumpkin or move the rotor(disk) away from it ( with shims).
Shimming the caliper would have increased the offset.
Maybe, in my case, the position of the output shafts changed because the OEM style bearings were NLA.

Exactly the issue I was trying to raise about some of our remarks on this site. While I’m far from knowing the specifics, I do know the rear differential side bearings were changed at some time. We need to have specific experience with the exact system a list member has in their Jag, AND if anything has been changed by the dreaded “previous owners”.
What is great is the fact that we have members with great experience on all variations, or at minimum, great experience with some specific models. Unfortunately after so many years and owners a newbie may not be aware of all the changes ‘someone’ may have made to our cars. Pictures are nice.
BTW, no one mentioned ride height regarding your rear alignment and with aftermarket and used springs some guys have, lord knows how far off the ground some of our cars end up.

Well I can’t say - maybe somebody can. I finally came to grudgingly accept (after many many years) that the factory engineers know a lot more about their cars than I ever will. The fact that you get some minor leakage indicates to me that there is probably enough air pressure build up from heat that it needs some relief.

I have to agree with Terry that the engineers had to know a lot more about this than I do, but that being said I can’t figure out what the heck that hole does other than provide a vent. On my latest rebuilds I have been plugging the hole. In my limited experience the grease comes out the hole rather than the getting to the bearings and I swear that the last one I worked on had a pound of grease there and dry bearings. I debated my decision but thus far no issues with plugging the hole. As Jerry would have said YMMV
Cheers,
LLynn

If you can find a spare finger while operating the grease gun, put your finger over the hole and pump away. This will allow the grease to get to the fulcrum bearings at the far end of the shaft.

Hello Jim,
It just goes to show how little those individuals know and the misinformation being regurgitated.
The hole is there as a vent when lubricating the fulcrum bearings via the nearby grease nipple. Because of the design of the unit and its lubrication system, grease will only get to the bearings if the whole of the air space around the fulcrum shaft is taken up with grease. Once that condition is met, grease will be forced into the bearings.

When the whole of the available air space, including that within the bearing, is occupied with grease, further application of grease using a grease gun will result in the grease taking the path of least resistance. If not for the vent hole, the grease would easily be forced past the original Felt Seals and just as easily past lips seals that are used as an alternative.

To ensure that grease does get to the bearings, as Bill Wayman suggests, block the hole with your finger until you can resist it no more. With regards to creating a mess, if you care enough to grease the Fulcrum Shafts, its not much of a leap to take a rag along to wipe away any grease that does exit the hole during the procedure. I have rag available with me to wipe the grease nipple clean, no matter which one it may be, before and after the greasing operation.

Regards,

Bill

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How about the hole for grease on the upper portion of the hub with the cap? Do you pump as much grease as possible in there and then replace the cap? No zerk is available. Both my caps have vent holes that weep grease after long tours. Maybe I’m overfilling and this is how extra grease is flung out? I figure more grease is better than less grease, but it gets messy.

–Drew

Hi Drew,
If I’m understanding you correctly I’m pretty sure that’s what Jerry did, when I rebuilt MIK’s IRS the hub bearing cavity was packed solid with grease. YMMV :wink:
Cheers,
LLynn

@L.Lynn, I use SuperLube and I don’t think it is quite as thick as other greases so that my be why mine gets flung out the weep hole. That and driving 5000 miles in two weeks in warm to hot weather.

–Drew

There was an earlier topic about this (probably the last of several) and I thought the consensus, backed by documentation, was the hubs were to be filled with grease.