Hi,
I currently make a list of parts I need to replace the output bearings and seals of my '71 S3 differential. My problem is that I don’t understand how exactly the oil is sealed from escaping at the output shafts. The parts manual as well as the drawing on the SNGB site only show an O ring. However, I was expecting it to have an oil seal similar to how the input shaft is sealed???
Thanks, Manfred
I dunno if it’s still true, but at one time you could buy output shaft assemblies preassembled, I guess on an exchange basis. Might be a good idea for some, as it reportedly is not a simple matter to get that thing preloaded correctly.
I also understand there are different designs, like using a duplex ball bearing vs. a pair of roller bearings or some such. I think the output shaft assemblies are interchangeable.
If you never wanna do this job again, you might consider upgrading the inboard rear brakes to vented rotors. The whole point is that vented rotors run cooler, and hence don’t conduct as much heat into those output shaft seals.
http://www.jag-lovers.org/xj-s/book/InboardBrakeUpgrade.html
Oh, BTW, I presume the diff on a ‘71 has a drain plug and the output shafts are held in place with 5 bolts. That is the unit we call a “Salisbury” – even though after about 1989 it was actually manufactured by Dana. For about a year there in 1987-88, Jaguars were fitted with a diff that had three bolts retaining the output shafts and no drain plug, and we refer to that unit as a “Dana”. Nuthin’ really wrong with a Dana except it’s not as simple a matter to service them – parts are harder to come by – so typically when a Dana needs service it is swapped out for a Salisbury. The brake calipers attach to the output shaft flanges on a Salisbury but directly to the diff case on a Dana, requiring access holes in the rotors to R&R the calipers on a Dana.
I’m just making this clear so you don’t get confused trying to buy parts.
Hi Manfred…there is an oil seal and it fits into the flange that the output shaft slots into…its not shown in your diagram or on diagrams on SNG site i just looked…it is detailed in the Jaguar service manual whete it details how to fit it…shims the same size/shape as the flange must be fitted to get a correct fit/mateing to the diff case .also be aware that the replacement output shaft bearings are different to your original type and require spacers…this is the seal on SNGB https://www.sngbarratt.com/English/#/UK/parts/9965883e-d5b7-480d-b0c0-3685f14b952f
Hello Manfred,
Unless your differential has been swapped post factory assembly, it will have a Salisbury Differential.
There are two Seals used per side, one an “O” placed close to the bottom of the bore in the Differential Housing into which the Output Shaft/Bearing assembly is located, the other, a Lip Seal that is pressed into the Output Shaft Flange. The following picture show the arrangement of the Seals.
The Outer Face of the Lip Seal should press against the Face of the Outer Race of the Bearing. The following picture shows that when the Seal is seated in its cavity in the Output Shaft Flange, the outer face of the Seal should stand proud of the Face of the Output Shaft Flange.
The correct bearing for the Output Shaft of your Differential is no longer available and this has been the case for many years. The original Bearing was a Double Row, Angular Contact Ball Bearing Race, that had a split Inner Race. Pre-load was built into the Bearing, and the design was such, that when the two halves of the Inner Race were drawn together until their Inner Faces made intimate contact, the correct Pre-load was achieved,
The Bearing being offered as a replacement is 2.0mm narrower, is a Double Row, Angular Contact Ball Bearing Race, with no split inner race, and no Pre-load, This Bearing has slight clearance in its assembly and nothing will change that,
This Bearing is supplied by the Usuals with two spacers (one each for the Inner and Outer Race of the Bearing), to make up for the 2.0mm lost in the width of the bearing. The Spacers are assembled so they contact the outside faces of the bearing and the Lip Seal in the Output Shaft Flange, will press against the face of the Spacer for the Outer Race of the Bearing.
Earlier and Later differentials used two opposing Taper Roller Bearings (one set of two per Output Shaft Assembly). The later system was used from S2 XJ6 and XJS cars onward. Although, Dana differentials were used for a short time in XJS cars.
The whole Output Shaft assembly using the opposing Taper Roller Bearings is interchangeable with the original Double Row, Angular Contact Bearing system.
Regards,
Bill
Hete are some pictures and the assembly process of my Salisbury diff output shafts with the two tapered roller bearings.
Thanks for all the responses so far. You all were very helpful, and I now know, that there is indeed a lip seal on the output shaft which ist shown as a separate part in the parts manual. I will report back how I did with the replacement of the seals.
When the mounting bolts are torqued down, is that seal face supposed to get crushed down to flush with the output shaft flange?
No, An allowance is made when calculating the Shims used between the face of the Flange and the Diff Housing for a 0.076mm (0.003") squash of the Oil Seal when fully tightened.
Regards,
Bill
OK, I see that. So, the outer ring of the seal pressed against the outer race of the bearing is supposed to form an oil-tight seal? Because otherwise oil could leak out through the shim pack?
Original ones used leather seals and was a real challenge to get them not to leak. Best way to fix is use the later axles. Much easier to install and they have a better bearing and seal design.
Hello Kirbert,
Yes, but the shims are supposed to lightly coated with Hylomar just before final assembly.
Hello Dick,
The OP is referring to the Diff for an S3 car. They were never equipped with Leather Seals for the Output Shafts. The Pinion Shaft Seal, yes; Output Shafts, never.
If the original Double Row, Angular Contact Bearings with the split inner race were still available, they would be the best choice; it was/is a good design concept. However, in their absence, the opposing, Taper Roller Bearing system is the way to go.
The correct Output Safts and Flanges that use the Taper Roller Bearings are becoming hard to get. There is a “Metal On” condition in the right places of an Output Shaft from a Salisbury Differential used on S2 and S3 car, to turn them into Taper Roller Bearing System compatible, but the Flange would have to me made anew. Accordingly, I’m contemplating supplying the whole assembly on an exchange bases for the Output Shaft.
Regards,
Bill
I really don’t trust Hylomar for anything other than dressing gaskets. Since those shims are not gaskets, I wonder if switching to Loctite 518 there would result in fewer diff leaks down the road.
Hello Kirrtbert,
I only stated what was recommended by Jaguar in period.
I don’t like Hylomar all that much; it starts to cure too quickly for my liking if using it from the tube and therefore, is hard to apply an even film. The aerosol pack version is much better for depositing a consistent film thickness, which I believe would be desirable when used to seal the Output Shaft Flange Shims. I use a Permatex product, but the Loctite 518 product would be OK.
Regards,
Bill
