Front wheel bearings question

[BobV12]

Hi all, I’m rebuilding the front hubs (1973 S3 OTS) and have pressed in new bearings and oil seal. I am re-using the stub axles but both have a slight ring on them in the position of the inner race.

The design of the hubs, with the nut adjusted to leave end float, leaves both bearing races seemingly able to rotate on the stub axle, potentially cutting into it. With the rear hubs it is necessary to press on the bearing races presumably meaning this can’t happen.

Have I misunderstood or do the front hubs have a design fault?

Happy new year!
Bob

[mgcjag]

Hi Bob..........the wear ring on the stub axel is typical and caused by the bearing spinning...which it shouldnt do.....Its not uncommon to find heavy wear and a deep ridge at the 6 o/clock position on the axels with most wear...........the bearings ideally should be a tight fit on the axel to prevent them spinning but its not uncommon for them to be looseish...........also over tightening the center adjuster nut exasperates the problem and can cause them to spin more...........the simplest solution is to loctite the inner bearing where it fits on the shaft........or fit bearings and shafts that have a tight fit......which isnt easy to find with off the shelf parts..........its also possible to fit aftermarket bearing spacers that lock the bearings to the axels so they cant spin on the shaft.....you then adjust with shims.......more info here viewtopic.php?f=3&t=17076&p=139986&hili ... ef#p139986 & on the forum if you search front wheel bearings......note the spacer i show is for S1 S2 cars.....S3 have a different size axel and need a different size spacer ............ Steve

[abowie]

https://www.sngbarratt.com/English/#/UK ... %20axle%60

Stub axles are available new for a pretty reasonable price, although it seems that SNGB are currently out of stock.

As Steve says you need C27787 which is specific to the S3 and XJ cars.

[angelw]

Steve Wrote:

note the spacer i show is for S1 S2 cars.....S3 have a different size axel and need a different size spacer.

Hello Steve,
The only difference between the Front Stub Axle for the S3 E and earlier E Types, is the length of the Thread that secures the Stub Axle to the Stub Axle Carrier and the Steering Arm to the Stub Axle/Stub Axle Carrier assembly. Accordingly, the Spacer used between the Inner and Outer Bearings is the same for all models.

The following picture is of an S3 Front Stub Axle that I manufacture. The Inner Bearing Journal is made as an interference fit for the Tapered Roller Bearing Cone.

Regards,

Bill

[mgcjag]

Hi Bill......thanks for confirming........i knew there was a difference was thinking of the later xjs with the thicker shaft.....cheers..........Bob..bearing spacer also available from SNGB.........Steve https://www.bighealey.co.uk/front-wheel ... er-jsuf141

[BobV12]

Thanks guys very helpful to know I haven’t misunderstood this apparent design issue, I will investigate the spacer and shim modification further. Presumably you would still leave it clamped up but with tiny end float like the rear hubs

Cheers
Bob

[angelw]

Bob Wrote:

Presumably you would still leave it clamped up but with tiny end float like the rear hubs

Hello Bob,
Yes, the logic of the Spacer is that the retaining nut can be torqued up tight (but the split pin should still be used), thus clamping the bearings and spacer solid along the long axis of the axle and therefore, preventing the bearings from rotating. Using the spacer allows the bearings to be set in either End Float, or Preload. Preloading the original system will simply guarantee that the bearings will spin on the axle.

Regards,

Bill

[BobV12]

Bill thanks for confirming

[abowie]

I will investigate the spacer and shim modification further.

Cheers
Bob

The problem with the spacers is that they cost more than new stub axles.

https://www.sngbarratt.com/English/#/UK ... 0spacer%60

[mgcjag]

Hi Andrew.....very much cheaper from Dennis Welch......see the link in a post above....

[abowie]

That's a lot more reasonable.

[rfs1957]

I can confirm that Welch supply a pretty nice product, at a reasonable cost.









The machining looks to be nicely done, and both my axles took exactly 0.60mm (24 thou) to reduce their end-floats to zero.

This could be easily and repeatably felt with a pair of jemmies between the hub carrier and the disc, where even 4 thou slop translated into easily-felt motion, so you can shim here with some confidence.

I shimmed with Ducati bevel shims to get those measurements, but now I know what range I'm in I have now ordered the Welch ones as the Ducati ones are a 1mm out on the bore.




Fitting couldn't be easier, as you just pop out the oil-seal and the inner bearing cone, only, then slide the spacer into the tunnel full of grease, replace the bearing and the seal, and shim under the cone of the outer bearing, once you've removed the handful of grease you'll have displaced.



While on the subject, what split-pins do people use here ?



The 1/8" ones I use - seen above - feel a bit feeble, as in practice they're well under 3mm - yet whilst 4mm ones will go through both the castellated nut AND the hole in the end of the axle, the alignment isn't good enough to enable the use of the 4mm through both at once.

[mgcjag]

Hi Rory..no other replies so just me at the moment..not specific to hubs but typically I go for the largest split pin I can fit..even if it needs a light tap through...Steve

[Gfhug]

As most split pins now available are metric then using the next size up and drilling through as appropriate seems to be the best option and is what I’ve done.

Just to add Light Aero Spares have US spec split pins imperial sizes such as 5/32 which might help:

https://www.lasaero.com/products/article/Q4488XY5

Geoff

[jannickz]

The design of the front hubs on your 1973 S3 OTS does have a potential design flaw that could lead to wear on the stub axles. The inner bearing race is not pressed onto the stub axle, but rather relies on the end float of the hub nut to keep it in place. Over time, this can cause the bearing race to rotate on the stub axle, eventually wearing a groove into it.

There are a few things you can do to minimize this wear:

Make sure the end float of the hub nut is set correctly. Too much end float will allow the bearing race to rotate excessively, while too little end float will preload the bearings and cause them to wear out prematurely.

Use high-quality bearings. There are a number of high-quality bearings available for your S3 OTS. These bearings are designed to withstand more wear and tear than standard bearings.

[bitsobrits]

You can also install tapered bearing spacer tubes (and use precision shims to set the desired end float or preload). The spacer/shims allows the bearings inner races to be clamped tightly and precludes rotation of the race on the stub axle. Also helps eliminate pad "knock back" and gives a better feeling initial brake pedal. It's really surprising to me Jaguar didn't do this from new, while less expensive marques (MG) did so.

[angelw]

jannickz Wrote:

Make sure the end float of the hub nut is set correctly. Too much end float will allow the bearing race to rotate excessively, while too little end float will preload the bearings and cause them to wear out prematurely.

It's fairly much the opposite to what you have written.
Without some method of securing the bearings so that they can't rotate on the axle, pre-loading them will ensure that they rotate on the shaft.

Tapered Roller Bearing prefer to operate in pre-load and correctly pre-loaded Tapered Roller Bearings will have an extended life compared to the bearings being set with slight end float. Excessive end float will result in shortening the life of the bearing, as will excessive pre-load. However, the degree of preload beyond optimal is greater than the degree of end float beyond what is deemed optimal, before the life of the bearings is affected.

Regards,
Bill

[rfs1957]

Could user « jannikcz » elaborate on his interest in the cars ?

Advice that is proffered so authoritatively, but which is so wide of the mark, makes me dubious.

His messages both in this string, and in another current one relating to bearings, read like they were generated by AI - ChatGPT etc

Fortunately we have « angelw » looking after our best interests.

[madjack4]

If jaguar had a design flaw all early fords like cortina escort anglia all early vauxhalls had the same flaw it was the done thing in the day. We tend to look at etypes as one offs these cars were never designed to last 50 years jaguar would have expected them to only last 5 or 6 years not time for stub axle to wear away Loctite the inner race it will be perfectly ok. I think you all worry too much about it lets face it if the inner race spins a small amount like 90% of the 60s and 70s cars did it will not cause any problem .My s3 roadster has wear on stub ive been to south of France and all over 4000mls last year in it no problem most etypes never go more than 500mls a year

[bitsobrits]

All well and good until the worn stub axle fails and the wheel departs for the shrubbery.