First post on this forum. Thanks in advance for any input and advice. I have the rear IRS dropped on my series 3 e-type for brake work and noticed the pinion seal is leaking. Is it possible to replace the pinion seal only without complete disassembly of the final drive? The shop manual says it’s impossible to just replace the seal since relaxing the pinion nut wont allow proper preload of the gears without a full rebuild but wondered if anyone else has completed this successfully. Just scribe the nut and reinstall to the same orientation is what I’ve done on others but never done one on this vintage Jaguar IRS.
Inofficially, yes, that can be done as long as the position is marked. Welcome!
David
Yes as posted above…iv done it and it works…replace seal and the thin paper gasket under the seal…you must get the nut back to its original position so mark nut and pinion and count the number of turns to remove the nut…if you dont count then you can get your marks lined up with every turn but not get it to the same position…either a new locknut…or locktite…Steve
DON’T CHANGE THE LOCKNUT!
That would change the preload in unpredictable ways.
You can mark the position. Count the turns and retighten to just past the mark. Think of it just past enough to be sure you have tightened to the mark but not less. Use Locktite Blue to be sure.
I haven’t seen a gasket behind the new seal in years. The seals have changed in style and proper ones come coated with sealant.
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There are at least three different types of diffs used in that period jaguars. By different I mean they are all dyna 44’s but they have different set ups for preload and different hub bearings - in particular Ser 3 E Types. I had a leaking seal on a Ser 3 XJ 12 diff
I’d rebuilt three years before, and installed in my 67 E Type. It used collapsible spacers. I did the marking nut bit etc replaced the seal and 300 miles later rebuilt the diff again. At least one bearing had shed some material, and all had to be replaced. I’d not so soon ignore the manual. Maybe Bill Angel will comment on this. .
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Hello Terry,
Salisbury differentials were used in the E Type. Dana diffs were used for a short time with the XJS.
There were three types of Salisbury diffs used with the E Type. Type 1 and 2 used opposing Taper Roller Bearings on the Output Shafts, with the type 3 using Double Row, Angular Contact bearings. The Double Row, Angular Contact bearings was an excellent system, as the pre-load was built into the bearing via a split centre race. Accordingly, setting the correct pre-load was a simple matter of tightening the nut that secured the bearing. Unfortunately, this bearing hasn’t been available for many years, with no scope to adjust the pre-load with the bearing used to replace it. There was also a difference in the method used to set the Pre-load of the Pinion Bearings between the Type 1 and subsequent Type 2 and 3 differentials, in that the Type 1 used shims whilst the Type 2 and 3 used a collapsible spacer.
From Series 2 XJ6 and other Jaguar models circa that period, opposing Taper Roller Bearings were again used for the Output Shafts.
There is a lot of wrong information contained in the Jaguar Manuals and particularly the S3 Manual where the description for setting the pre-load for the Pinion Bearings is to simply torque the Companion Flange Nut to between 120 and 140 lb/ft torque and if you were to inadvertently exceed 140 lb/ft torque, then the collapsible spacer must be replaced. There would have to be a whole flock of ducks inline for that system as stated to actually work.
The collapsible spacer is pre-weakened by being partially collapsed and the more it’s collapsed, the weaker in axial load bearing it becomes. To get the spacer to start to collapse further than when in its new, as received state, invariably it takes well over 140 lb/ft torque just to get it moving; sometimes considerably over 200 lb/ft torque.
The correct method of setting the pre-load of the Pinion Bearings is to measure the amount of torque required to start the rotation of the Pinion Shaft and keep it rotating (without the diff centre installed). In the Series 1 E Type Workshop Manuals, the torque specified was circa 12 lb/in, while in effectively the same differential used in the XJS, the torque specified is circa 26 lb/in. This is evolution and therefore, I use the higher specified torque of the XKS when refurbishing all E Type Jaguar differentials. There is a tendency for the Pre-load of the Pinion Shaft to diminish under hard acceleration, therefore, if the pre-load is insufficient, a slight end float condition can exist whilst accelerating resulting in a slight change of engagement of the Crown-wheel and Pinion teeth and noise.
There would be nothing wrong with replacing the seal by marking the position of the original nut. At worst, the pre-load will be circa what it was before replacing the seal. If the bearings have some considerable miles on them, then there is a chance that the pre-load has diminished. The Companion Flange Nut is a Cone Lock style and is supposed to be single use. Accordingly, to use the same nut, a Thread Lock Loctite product should be used as insurance.
With a bit of practice, with the diff centre installed, the correct pre-load can be set using the method of measuring the torque required to rotate the Pinion, by taking the measurement through the backlash movement of the Pinion Shaft. Turn the Pinion Shaft until the teeth of the Crown-wheel and Pinion are in contact, then measure the torque to start the rotation of the shaft in the opposite direction.
Regards,
Bill
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Thanks for the detailed help. Is there anyway to verify what differential I’m dealing with without too much disassembly? The IRS was rebuilt at some point and I don’t have history to know how authentic it is to a series 3 Xke.
So if the bearing is worn and the differential is whining, a little tightening helps?
Hello Chris,
Its highly unlikely that the original diff will have been replace, therefore, it will be a Type 3 Salisbury that uses the Double Row, Angular Contact bearings on the Output Shafts. Although your Thread is dealing with replacing the Pinion Shaft Seal, given that you mentioned that the IRS unit is out to work on the brakes, the retainer for the Output Bearings doubles as the Mounting Bracket for the Rear Calipers and can easily be removed to check what bearings are installed without upsetting any settings of the differential.
If the original Output Shaft Bearings have been replaced, you will find two x 2mm thick spacer rings just inboard of the Bearing Retainer/Caliper Mounting Plate; one for the outer race and one for the inner race.
The opposing Taper Roller Bearing system is infinitely better than the Double Row, Angular Contact Bearings with no available pre-load setting. The Taper Roller Bearing system can be interchanged with the Angular Contact Bearing system as a complete assembly of Bearing Housing/Caliper Mount Plate and Output Shaft with absolutely no modification to the Diff Housing required. If you can find an assembly set from an S2 XJ6 onward, or other cars using the Salisbury Diff, you can exchange what you have with them. However, they are becoming quite hard to find.
I’m having the castings done to manufacture the bearing housings and there is a “Metal On” condition of the Output Shafts that use the Double Row, Angular Contact Bearing, so that they can be machined to conform with the dimensions of the Output Shaft that’s used with the Taper Roller bearings. I machine these on an exchange basis and supply as an assembly, including bearings adjusted correctly, ready to assemble with the diff housing.
Regards,
Bill
Hello David,
If the whining is in sync with acceleration its highly likely that the pre-load is insufficient. To tighten the Companion Flange Nut past a witness mark made would have to be done within the scope of the correct pre-load. This can be achieved via the method described above by measuring the torque needed to rotate the Pinion Shaft through the Backlash movement of the Pinion Shaft. Being a used, worn bearings, i would be inclined to use the lesser torque of 12 lb/in.
Regards,
Bill
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When you say that, what would you estimate the typical life before rebuild for the one type differential over the other form the factory?
Tom
Hello Tom,
As I stated in my previous Post, infinitely better than the Double Row, Angular Contact Bearings with no available pre-load setting. The Double Row, Angular Contact Bearings that had the split centre race was a good solution as the pre-load was built into the bearing and no adjustment was required. As far as which system would last the longest would be line ball.
Regards,
Bill
Got me worried there, I don’t see that anywhere in the Series 1 SM, is that specific to S2?
Hello Randall,
There is no difference between measuring the Pinion Bearings’ pre-load of a diff from an S1 car (Type 1 Diff) and later Type 2 and 3 differentials. The method used to measure the pre-load is by measuring the torque required to turn the Pinion Shaft. This needs to be done without the load applied by the Crown-wheel and diff centre. Accordingly, that’s difficult to achieve after the diff has been completely assembled. Marking the index position of the Companion Flange Nut and returning it to the same position is no gauge for correct pre-load. However, at a pinch, you can get there by measuring the torque required to start the rotation of the Pinion Shaft through the Backlash between the Pinion and Crown-wheel gears.
With the diff used in the S1 cars, the pre-load is adjusted via shims. Therefore, there is no need to mark the index position of the Companion Flange Nut, simply torque the nut to the specified value. Because the shims are acting on the face of the inner race of the bearing, a surface that is not subject to wear, exceeding the previous pre-load is not possible. If the bearings have some miles about them, its likely that the pre-load will have diminished since it was last set correctly. Adjusting the pre-load of a differential that uses shims, such as the Type 1 diff used in the S1, is difficult at best and generally not possible without removing the diff centre. The fit of the inner race of the Outer Bearing of the Pinion Shaft varies between a very close running fit to slight interference (referred to as a transition fit). The adjustment requires that the Outer Bearing be removed so as to vary the thickness of the shim stack. Accordingly, if the fit of the bearing is an interference with the Pinion Shaft, your chance of removing the bearing without damage will be in the order of Buckley’s and None without removing the diff centre.
Regards,
Bill
Chris,
You may want to visit Bernard Embden’s web site - Bernard Embden's Jaguar Website - for your answer. As I recall he did a pictorial on how to replace the seal with the IRS installed.
Happy Trails,
Dick
Thanks Bill, that’s what I thought, so there’s no problem just changing the pinion seal.
Thank you Bill. It’s not much work but too much for trial and error, for me it’d be better to do it right I think.
If anyone is into it, there was a Wheeler Dealers Episode on TV where he simply changes the seal and magically, the car immediately sells for at least a million quid. It shows the process, although it really is straightforward and not specific.
Thanks for all the insight and help. The pinion area of my final drive does not look like the new pinion seal I have. Does this look correct for a series 3 XKE. The IRS unit has obviously been renewed at some point prior to my ownership in the mid 1990’s I’m just unsure of its full authenticity or if more modern changes were made. Here is a picture of the companion nut and pinion area of what I have. Any thoughts?
Looks mormal to me with the old style leather seal mounted in a metal outer…different to the modern replacements…when you pull the flange look at the surface thats been running on the seal…if its worn then the new seal will leak…so either fit a new flange or fit a speedi sleeve…Steve
Thank you. That makes sense to what I’m seeing that there will be a leather seal mounted in the metal outer that’s currently visible. Just wanted to double check before I progressed any further to try to make sure I didn’t run into any surprises. The only other IRS I have seen previously must have been modernized to a silicone seal since I’ve never seen one look like this before. I just assumed this one was as well based on its condition but like I said I have little history to this particular IRS prior to my ownership.