Front hub bearings

[Orkney]

Hi Folks,
Been doing my spare front upright to replace the wheel bearing which was an advisory on the MOT which came with the car - successful dismantling with some home made tools and a bought Rotor Nut socket (made by Laser tools and was £21) I trawled the web a while back and found a You Tube video which appeared to show a Taper roller bearing and the old one is definitely a 2 row ball unit. Is there a taper roller alternative (perhaps R models) which will fit the early hub? Needless to say I can't find the video clip now - a link from a link. I'd rather use taper rollers any day than that under-engineered original.

Best regards,
Ian

[robv12]

Ian, I have never come across an alternative, all the seminars and 308 stuff I have been to and learnt from, an alternative has never been mentioned, if you find something let us know

[Brakebuster]

the bearing changed in 1998/9 to larger diameter units in the later cars , maybe they changed from ball to roller to ,
but there is a definite difference between the years

BB

[robv12]

yes the later cars are a larger diameter, but of the same design

[Orkney]

Thanks for the info Rob and BB - I have now fitted the refurbed upright on the car which is a Jan 99 reg (866 are the first 3 of last 6 on VIN) and the old and new are the same part number so both twin row ball. It's a pity Jaguar moved away from 2 wider spaced taper rollers in such a high load application. It was an advisory in Dec at the MOT and barely noticeable but following a lovely 700 mile round trip down to Glencoe last week it was howling pretty loudly when we got back and lots more play. Anyway, all sorted now and quiet as a mouse. I toyed with the idea of sourcing 2 taper rollers and machining a spacer to eliminate play when the rotor nut is torqued up but couldn't find anything with those sizes. I was very careful pressing the bearing in and the hub into bearing to make sure I put zero load on the balls - so I'll see how many miles this one does. I put a step by step guide on my site if anyone needs it.
Thanks again,
Ian

[oldtimer]

Hi All,
When asbestos free brake pads were introduced -when was that ! back in the eighties I think.
Many problems emerged, particularly with brake judder. The maximum recommended brake disc run out was, I think 40 microns, what ever that is in real money. That means the allowable run out is 2/5 of naff all.

Up until this point most vehicles used two taper roller bearings per front hub with an operating end float of 0.004 thou. With this sort of end float the almost zero disc run out was unobtainable.
It is at this point that the twin, deep groove, sealed for life, ball race was introduced which eliminates the excessive end float previously described.

While on the subject it is opportune to mention the absolute imperative of ensuring the disc mounting face is as perfect as possible. I use a 1/2 inch square stone about 8inches long dipped into white spirit to carefully clean the mounting face.

Brand new discs are often dipped into an anti-corrosive preservative and need to be cleaned off to perfection. Mounting a clean disc onto a clean hub will improve the possibility of achieving the desired run out figures when using a DTI.

Failure to achieve excellent run out figures will result in brake judder at a future date. Brake judder can be confirmed by removal of the disc and marking the outer edge at eight points of the clock. Then using a micrometer measure the disc thickness at the eight points previously marked.
Transcribed these measurements in a straight line on a sheet of paper in the form of dots, join up the dots and this will give you the wave form sympathetic with the vibration or judder. Think about it!

Oldtimer

[J44EAG]

H2So4, Professor Phil. May be even TSR2.

Nice one indeed as an explanation. Logical indeed.

The reciprocal of pie or similar to you good wife!

Mike