Final drive pinion oil seal 1971


(Paul Wigton) #21

Still got mine…I’ll try to find it and take a pic!


(Lee140FHC) #22

Once the crush sleeve is compressed to the correct thickness, it effectively becomes just a very thick “shim”, so using the torque spec for the SHIM-type pinion strategy should work just fine. Of course, that does assume the pinion pre-load was correct in the first place. Easy enough to check: just tighten nut to any reasonable amount of torque, then push/pull/twist the pinion to make sure it has no play and has some resistance to turning. Now you can fully torque the nut to the shim-type spec…I can’t imagine the torque quoted by Mr. Reilly would be enough to crush any sleeve…it took about 3-400 foot pounds to compress/crush the sleeve on the Ford 8.8" I recently rebuilt…same with the 9"ers I worked on. Lock-tight should have virtually no effect on torque readings that high, BTW.


(Frank Andersen) #23

**
The specs listed is from 70 lbsft initially for older cars and starting at 120 for newer cars, Lee - the point where the sleeve starts to crush…

But crush effect, sleeve compression, increases with torque to some unspecified value. The trick is to stop torqueing when the sleeve is compressed enough to give the proper bearing play as measured by the specified force required to turn the pinion.

So the torque required may well reach high figures, though it depends on the composition/configuration of the sleeve. Which again may differ between diff manufactures, and indeed production year - as indicated by the difference between older and newer specs for ‘our’ Jaguars…

The point is that if the initial torque is exceeded, the sleeve will compress further, as you imply. Which will give too little lash - requiring replacing the sleeve. And indeed, as torque generally holds the assembly together some 150 lbsft may be adequate for that purpose - and too little to further compress the sleeve…

Al depending of course that the lash was originally set to specs…:slight_smile:

Frank
xj6 85 Sov Europe (UK/NZ)
**


(Robin O'Connor) #24

Its going to be interesting to hear the outcome of this endeavour as to whether the OP goes with re-torquing or counting turns :slight_smile:


#25

Its going to be interesting to hear the outcome of this endeavour as to whether the OP goes with re-torquing or counting turns.

It will be a couple of weeks before I get round to it (still rebuilding the front suspension and brakes at the moment) but I’ll let you all know how it goes.

Frankie


(Rob Reilly) #26

I was quoting the factory Service Manual pg 51.25.19 pp 88.

There is also another interesting instruction here:
“On no account must the nut be slackened off and re-torqued, as this will result in incorrect preloading of drive pinion bearings.”

And another:
“Caution: Exercise the greatest care when torqueing companion flange nut as overtightening will necessitate almost complete dismantling of final drive unit to replace collapsible spacer.”

It would appear that the factory engineers would not approve of the alternate methods we have been discussing here in our hope of avoiding a complete disassembly just to replace a seal.

Lots of other interesting stuff in this manual. For example, did you know, the pinion and crown are matched sets, lapped together at the gear factory and marked with serial numbers and tolerances.


(Lee140FHC) #27

Oh yes, they are lapped, then marked by the amount of deviation from standard pinion height…say, + .005, or - .004, etc. There are 3 types of gear sets with regard to pinion vs ring gear tooth count: hunting, non-hunting, and partial non-hunting. This spec, however, is only important when reassembling used gears…thankfully, not the case with the OP 's situation.
The torque specs as quoted in the manual do, indeed, suggest a VERY weak crush sleeve system…a spec easily exceeded by any, quality 3/4" - 1" nut…think suspension parts here. I’ll have to check my manual as IIRC, the pinion nut spec on (our) Salisburys is reasonably high, even without a sleeve to crush…interesting.

I did check the 120/140 manual, and, as usual, no torque spec was given. Then I checked the E-type manual I had and found that the shim-type system calls for a torque of 120-130 ft/lbs. My Datsun Roadster manual calls for the same spec, although the Roadster diff is smaller than the Dana…but is also a shim system.
So, I’m still dubious of such a “low” torque spec to crush a steel sleeve, given the non-crush sleeve specs, FWIW.
But either way, the only recommendation I would change to the OP would be to use high-strength loc-tite instead of medium strength…assuming he does not know the original removal torque AND goes with the 120 ft/lbs spec. I’ve had success with this method on heavier duty diffs before.


(Pete55Tbird) #28

Rob_Reilly

Lee140FHC1
2h

Lee140FHC1:

I can’t imagine the torque quoted by Mr. Reilly would be enough to crush any sleeve

I was quoting the factory Service Manual pg 51.25.19 pp 88.

Rob, I think that in a more perfect world people could just have the Jaguar garage come and collect
their broken machine and have it repaired regardless of effort and or expense. Most of us do not live
in that world and we do what we can with what we have.
Just because “the manual” outline their procedures does not mean other procedures can not be used
successfully. Over many years other methods and technique have evolved to REPLACE “the manual”
way of doing things. There is very little to be gained by sticking to the past JUST BECAUSE.
Alternatives that are faster AND JUST AS GOOD can be tried. Pete


(tony) #29

One thing I do is measure whatever settings, such as measurable pinion turning torque, before
I dismantle

Using a inch pound torque wrench to measure “break away” torque on the pinion is a good start.

pressure to continue rotation is better, via a dial-type inch pound gauge, if you do not have one, small spring or electronic scales for weighing fish/luggage can easily be rigged to read it

that way, the pinion nut can be eased up to the old mark, while measuring the the “pre-load”…so that it is the same as before (assuming it was within acceptable range to start)

If you have access to the cover, check gear backlash with a dial gauge, can also using marking compound to check pattern

With the Jeep Dana 35, (similar design) they wear out big time, and if the pinion bearing lose their pre-load settings, they make a distinct noise, under load, up to about 60kmph


(Rob Reilly) #30

I believe I was merely quoting the factory manual for the general benefit of the forum participants. I was not giving an opinion.
The factory manual is warning that other shade tree mechanic methods may not be JUST AS GOOD.
The collapsible spacer or crush sleeve is intended to be crushed by a certain torque on the nut, and then will be in a condition where there is a slight spring back, pushing the forward inner bearing away from its seat a tiny amount, so that it is not in an overloaded condition.
If you overtorque the nut, there will be overload on the bearings.
If you can achieve this same tiny spring back with a second torqueing of the nut, it might be right. You could try to do it by feel, see how the shaft turns, stopping before you go too far. It might or might not be right, depending on your skill.
The factory is sort of implying they don’t believe anyone has this skill.
If you think you do have this skill, you will probably ignore the factory instructions.
Our purpose here is to see that Frankie is informed of all aspects of this operation before he attempts it.


(Pete55Tbird) #31

Rob, do you have any personal experience doing this? Pete


(Rob Reilly) #32

Yes, when I bought my 74 XJ12, during the test drive, the one thing I did not do was try it in reverse around a left hand corner. So a week or so later, when I backed it around a left hand corner, I heard a noise in the rear.
I found the axle had about 1/8 inch of end play. It turned out to be a case of shade tree mechanic-itis, some dolt had installed a wrong bearing in one side, and also failed to clean out all the chips and broken bits of the original bearing. Caveat emptor.
So I found myself completely disassembling and rebuilding the differential.
Unfortunately I do not remember whether the outer pinion bearing and spacer come out easily or are pressed onto the shaft. If they come out easily, I think the factory manual would have said so.
I’m a licensed professional mechanical design engineer and I’ve seen this idea of a crush sleeve in other applications in heavy construction equipment.


(Frank Andersen) #33

**
I’m not sure that it will work in-car, Tony - the specs are given for the ‘bare’ diff, without driveshaft/wheel drag…?

Frank
xj6 85 Spv Europe (UK/NZ)
**


(tony) #34

agree it includes axle turning force, but total is all you have to go by if you do it “in car”, the total turning force should be the same before & after.

this is assuming the PO, like myself, did not wish to do an entire diff rebuild in order to change a leaking pinion seal, and that he is reasonably satisfied, the pinion bearings are not worn

Interestingly, the Jeep Dana 35 FSM, which is a crush tube design, is very detailed, outlines the
above methods for changing the pinion seal, (ie measure torque first) and gives torque figures for old & new bearings & crush sleeve etc. The new crush sleeve force is quoted 200 to 350 ft lb.

The Dana 35 is a smaller version of the D44, which is similar to a Jag diff

I have done the pinion seal job in car on Jags, Jeeps, and IH Scouts, using the above methods, with no problems. I have seen it done the same way, by a vastly experienced mechanic

I have rebuilt a shim-style diff with, but not one with a new crush sleeve, a 3/4" Torque wrench is needed

It is up to the PO to decide how he wishes to proceed, this forum & Youtube are the friend of the backyard mechanic…at least it gives you a shot at getting it right, once you sort the differing methods


(Frank Andersen) #35

**
Initial assembly calls for increasing torque while repeatedly measuring turning force in the process, Rob. When the correct turning force is reached, the crushable has the correct thickness - and could as well be replaced by a plain washer.

If, during torqueing, excessive turning resistance is measured - the diff must be disassembled, and a ne sleeve must be fitted - starting the process again.

Changing the seal is a routine in-car operation, but is somewhat intricate - requiring backlash torque measuring. Ie, using the play inside the diff to indicate ‘pure’ pinion shaft bearing play. The nut/shaft position being then marked and the nut unscrewed, noting the release torque. The seal is then replaced and nut tightened to the marked position - and the backlash again measured, and is usually slightly higher due to the new seal.

Lee’s point is well taken; the crushable will not crush further unless the original torque is exceeded - lower torque than that will keep the assembly together, just as would be the case where ordinary shims/washers are used…

Unfortunately, the only proof of a well made pudding is the longevity of the diff and bearings - and no diff noises…:slight_smile:

Frank
xj6 85 Sov Europe (UK/NZ)
**

Frank
xj6 85 Sov Europe (UK/NZ)
**


#37

I have followed the advice with interest.

This is the Jaguar workshop recommended procedure for changing the oil seal.

It seems that it is not a question of either/or but a combination of both - the nut must be tightened to at least 120ft lbs and a pinion turning force of 25 in lbs to 45 in lbs must be achieved. I am not clear why the manual says that the force required to turn the pinion should be measured and recorded before dismantling because that value doesn’t seem to figure in the subsequent re-assembly instructions.

Interestingly in the preceding workshop manual section (re-assembly of final drive following overhaul) only a nut torque (120 to 140 ft lbs) is specified - there is no mention of the need to check the pinion turning force at all - just a warning that over tightening will necessitate a new collapsible spacer.

I don’t know if any of this affects any of the advice given so far?

Frankie


(Rob Reilly) #38

That’s interesting. Your manual is quite different from mine, which goes on for 10 pages and 90 steps. I left off a lot of that stuff because I thought this discussion was getting too complicated for what you wanted to do.


(Lee140FHC) #39

The other “odd” thing is that the turning torque is measured with the seal installed, which seems to me to introduce a variable based on how tight the seal is…oiled, greased, somewhat dry? Of course, it IS the practical way to reassemble. Over all, it seems to me the procedure as outlined in the above Manual page pretty much confirms the vast majority of advice given here…the 120 ft/lbs is NOT enough to further crush the sleeve and is simply the mechanism to keep “everything together”.
I suppose the “precheck” of turning torque is to warn the tech that a problem might already exist…too high of a reading requiring disassembly, too low, more crush needed upon reassembly. Note that it is mentioned that any measurement can only be accurate within the (tiny) lash amount/movement…a difficult measurement, to say the least.


(Frank Andersen) #40

**
Indeed, Lee - the point is that within the range of that movement only the bearing lash is measured…

Ie back off, then apply torque - overcoming the bearing resistance only; the flange starts moving. Hopefully at the spec torque - and indeed after seal is reinstalled a slightly higher torque is ‘prescribed’…

Frank
xj6 85 Sov Europe (UK/NZ)
**


(Frank Andersen) #41

**
Different diff, Rob…?

And I assume the manual covers a full diff overhaul - the changing of the oil seal only, should be relatively short?

Frank
xj6 85 Sov Europe (UK/NZ)
**