Front wheel bearing failure? Symptoms?

[BrianG]

I had the car serviced and MOT'd last week (117,000 miles) and all was well apart from a note that it was needing new front discs and pads sometime in the next 6 months. On a day trip to Calais, the trip down to the Channel Tunnel was fine but on the return trip (about 100 miles) I noticed a new whining noise, apparently from the offside front wheel. I thought it might be just a new tyre noise due to the heavy load in the boot; with these tyres I've noted weird noises occur on some road surfaces (tyres are half worn Dunlop Sport Maxx RT2). Testing the car again today with nothing in the boot the noise is still there and becomes noticeable once above about 50mph. The noise does change as you go over nice smooth patches of road, where and the whining seems to almost stop.

The noise does not occur when cornering hard at lower speeds. .With the wheel jacked up it does not have discernable play at the top and bottom. Spinning the wheel gives only a sound of the disc dragging slightly. Taking the wheel off to try and feel the hub for rough bearings is inconclusive as the disc then comes loose away from the hub on the studs, making it difficult to feel anything as the disc drags more.

I know that these bearing are not adjustable like those of yesteryear, so has anyone had a duff one and know what are the typical symptoms of a knackered one?

[J44EAG]

`With brake calipers and discs removed Brian, spinning the hub should find looseness and a gravely feel. It is also likely to produce noise. A new hub by comparison will feel well greased, very much smoother and be devoid of noise.....totally different.

In my experience with the X350 an XF and two S-types which share the same common hub, I found used front bearings not to have much play radially or axially but wear and attendant noise accumulated over about 75k miles was ALWAYS present and I`d always change them as a matter of course. Yes, they frequently soldier on for a while longer but I was never prepared to risk wheel bearing failure. Cost didn`t really figure. An after market bearing was generally about £35-£40 a piece.

I`m fortunate to have a bench press which made bearing replacement fairly straight forward. Its worth noting that corrosion between the old steel bearing cartridge and the ali vertical leg was always severe owing to the fact Jaguar never assembled the two components with either grease or Duralac barrier paste. That was a very bad decision. With the vertical leg complete with axle line drop arm removed from the car (Didn`t have a big enough ball joint splitter at that time), I`d dump the leg on the bench press, remove the rear black plastic ABS/inner bearing cover and load up the bearing case by ramming anything up to SIX TONS of pressure onto it from the press. If I was lucky, the old bearing cartridge would let go with a hell of a bang! That would move it about one eighth of an inch. A second pressing would move it about another quarter of an inch. After that the bearing would continue to come out but only minimal bench pressure was needed.

Once the old bearing is removed, the ali vertical leg will need a good clean up. Expect to find the new bearing cartridge to be a sloppy fit in the ali leg. This is because so much ali corrosion comes away from the leg when an old bearing is removed. That isn`t a problem. The two Torx bolts and two hex bolts which bolt the leg and bearing together are the load bearing parts in the equation. A gap between the cartridge and the leg doesn`t matter. Assemble the leg and bearing cartridge using Duralac paste to prevent reoccurring removal issues at a later date. New wheel bearings are pure joy. You will notice a difference once fitted.

Also consider the condition of your drive belts and idler pulley bearings on the front of the engine. Sometimes it is difficult to distinguish where noise comes from. Wheel bearings, belt and idler pulley bearing wear can sometimes be difficult to accurately diagnose. Finding out which area is producing the noise is often a common conundrum.

Mike

[PaulGover]

FWIW, I've not heard a duff wheel bearing "whine", more, as Mike says, a rumble at low speed. To quote the workshop manual "Bearing rumble sounds like marbles being tumbled. This condition is usually caused by a damaged wheel bearing."

The standard diagnostic is, AFAIK, an engineer's stethoscope, which is the same as a doctor's but with a spike instead of a cold disk. Mind you, I haven't seen a doctor use one for ages - they probably keep them with the leeches. You might be able to rig something similar out of a spike (like a steel knitting needle) and an ear-sized disc stuck/screwed to the end. You put the spike against the stub axle, the disc to your ear, spin the wheel and listen.

All that said, I'm currently stumped as what might be whining, though in these cars there are electric motors everywhere. Does the sound pitch vary with road speed, engine speed, or something else, or not at all? Does it vanish if you declutch?

If you have a copy of the workshop manual, there's a Diagnosis section for Noise, Vibration and Harshness near the front.

By the way, what model year? Your signature file lists all your other cars' ages!

[J44EAG]

Removal of the plastic ABS cover on the rear of the bearing gives direct access to the inside end of the stub axle and the inner bearing. A screw driver placed against the bearing and ones ear at the other end could well reveal a duff bearing.

As previously said, XF, S-type and X350 all share the same bearing cartridges. I`ve changed loads of them and by 70k miles of use, they have all sounded rough when the hub is spun. In my experience (15 years) with new bearings fitted, previously noisy cars have always then smoothed out. I`ve never known these bearings to be silent or smooth running from 70k onwards. Just my take on the matter.

Mike

[BrianG]

Well, it's still whining and now joined by rumbling/growling at lower at lower speeds or when braking! I have a weekend away planned in Gloucester so have had to resort to arranging a hire car, not wishing to chance the worsening XJ giving out miles from home. I've kept it to short local trips this week as I could not get either my local main dealer to look at it nor an independent, but It's booked in next week at Surrey Jag for repair - I hope it gets there (about 35 miles).

[J44EAG]

Ray will sort that for you, Brian. A top man and a pleasure to deal with. Please give him my best wishes.

Hub removal can be a nasty job with masses of corrosion holding the ali leg and steel bearing cartridge together. Usually it is the vertical leg off, split the bottom ball joint etc. Then comes the fun of loading the cartridge and leg to separate with a starting bench press pressure of about 5 tons. I used to hide around the corner from the press and remotely load the whole thing up whilst waiting for a colossal "bang" as the two parts separated! That was accompanied by a shower of corroded ali dust. Not a nice job.

Let us know how you get on.

Kind regards,

Mike

[BrianG]

My car is now all fixed by Surrey Jag Centre. Well done Ray & Co.! Not a bad price really, 2.5 hours labour and £154 for parts, total £410.58 including VAT.

For reference, they found no play in the wheel on the hoist and heard very little noise on the back of the hub using the stethoscope with the long probe and spinning the wheel buy hand. Yet on the way to their workshop the growling had worsened to sounding like a small motorbike at 50-60 mph. It just goes to show that not all symptoms are to the text book!

[J44EAG]

Inside the hub Brian,are two back to back bearings. I suspect they are ball bearings rather than needle rollers. Both are enclosed in the bearing cartridge units.

As previously said, I found the cartridges removed from an S-type and my current X350 to both sounded loose and gravelly with the discs removed. That at 70k and 80k respectively. On the basis of those previous two findings, I now see those units as ready for a change once they have covered that sort of mileage. £40 a piece buys you a non OE cartridge. £70 buys you something with OE grade heritage. Whether the two grades last the same mileages is hard to quantify. As usual, you pay the money and make the choice.

Ray at Surrey Jag is a top guy. His prices are more than fair and his guys produce top grade work. Highly recommended.

Mike K