The Range Rover 4.0/4.6/P38 had new lighter, stronger and greatly simplified axle assemblies. Among other things, the pesky swivel ball assembly was eliminated from the front axles -- considered heresy by the Luddites, who claimed the new rubber boot arrangement would never hold up off road. (In practice, my 4.0 has done nearly 160,000 miles -- "never been on road"!! -- without any attention at all to the rubber boots). Another simplification is that the wheel bearings are pressed into the hub, eliminating the need for the innumerable seals, gaskets, washers, spacers and other paraphenalia that makes the reassembly of a Classic hub impossible without referring to a diagram.

As a result, one of the few downsides to the improved axle design is that the procedure for replacement of the wheel bearings (according to the shop manual and used Land Rover dealers) is to replace the entire $500 hub assembly as a unit. More recently the bearings themselves have become available as separate parts, but you have to have heavy duty equipment to press them in. The hub procedure is described here mainly for the rear hubs on my 4.0, but the front is similar. Scott Kirn contributed the description of the procedure to remove and replace the bearings themselves, and the pix of the front hub assembly are courtesy of Lori Sickley. As always, Ron Beckett contributed is knowledge and was in charge of overall editing and vetting.

• Rumbling noise. (Can be confused with aggressive tire noise).
  
• Oil leak from end of axle housing (if you are lucky this might just be the $15 oil seal).
• Squeaking noise.
• Grinding noise (really bad!).
• Slop or play in wheel hub, evident when wheel is removed.
• Any uneven feel while rotating a wheel while off ground (eg jack up entire axle and try rotating the wheel).
  

The usual signs of worn wheel bearings are rumbling noises coming from the wheels. However, in my case the first sign was a high pitched squeaking sound coming from the rear of the vehicle (as if some item of cargo  was squeaking in the loadspace). A look underneath revealed a small pool of oil on the ground inboard of one of the rear wheels. I was able to drive the car home, albeit to the accompaniment of occasional unpleasant grinding noises. (Judging by what I found when I later dismantled the hub, the ideal strategy is probably to stop on the first sound from the hub and replace the defective parts immediately. However, this is seldom practical.)

Initially, I hoped that just the oil seal had failed and was getting chewed up by the ABS sensor reluctor on the axle. However on jacking up the wheel and removing the disc brake caliper (for procedure see 4.0/4.6 brake repair page), I found I was able to move the hub both axially and laterally!! Further exploration revealed that the wheel bearing nut was loose and its retaining pin was missing -- possibly the root cause of the bearing failure in my case. The various parts of the hub assembly were chewing themselves up and it was clear that replacement of the whole $500 hub assembly was definitely needed.

However if you catch the problem earlier and the failure is confined to the bearings themselves, you can replace just the bearings and outer race (about $200 -- see parts section below). Or, if the only problem is an oil leak with no play, grinding, squeaking or other problems coming from the hub, you can just replace the $15 axle seal. That's what I was hoping my problem was, but alas it was not to be!!

Bearing and race assembly. Dividing line between inner and outer bearings is visible.	Bearings removed from race -- one is visible at left. Photos courtesy of Lori Sickley.

In June 2007 we heard from a RR owner, Joe Pozzuto, who works in the bearing industry. He checked out the actual part numbers for the required bearings for his 1999 4.6 HSE. He confirmed the Timken part number is NP275832-90UAL.

In the UK, Joe Godfrey sourced these Timken bearings at Kaid Ltd for about £80 ($150). Mark Kelly reports that Britpart has the bearings for about £30.

In the US, DAP Industries sells an equivalent bearing under their part number FTC-3223B for $110. I also discovered the replacement bearings at Auto Parts Warehouse, who specify SKF bearings for front or rear on the 4.0/4.6 (2 per wheel needed) for $28.76 each or $57.52 per wheel.

If you have tried using generic parts for this job, please email me!!).

Axle Seal

ABS Sensor Adapter

The shop manual advises the replacement of the outrageously priced $35 adapter with associated rubber collar that houses the ABS sensor. This advice can be taken or ignored according to your taste (I ignored it). The part is nothing more  than a springy friction fitting that holds the sensor from moving in and out. If the sensor seems to be too loose in the hub, you could try removing the adapter and bending it to make the fit a bit tighter.

Tools

• Large 1-1/4" AF socket for wheel bearing nut.
• 1/2 inch AF 12 point socket for removing brake caliper bolts (3/4 inch AF for front calipers).
• 13mm socket for removing hub assembly.
• 13mm combination wrench for removing bolts the socket won't reach.
• 8mm socket for removing brake rotor mud shield.
• Impact wrench with large Phillips head for removing brake rotor screw.
• Pliers for yanking out the ABS sensor.
• If replacing bearings only and keeping old hub: Hydraulic press (at least 20 tons) for bearing removal and refitting, and acetylene torch for heat application.
• IF replacing bearings only and keeping old hub: Die grinder or similar for removing inside bearing race from hub shaft.
  

Removing the Hub and Axle

Prior to jacking up the appropriate corner and supporting it on jack stands, you can pop the center cap of the wheel off and access the staked nut that holds the wheel hub (photo below left). It is easier to loosen this a bit with the wheels still on the ground to resist the torque you apply.

Wheel with center cap removed for access to staked wheel bearing nut (stake missing).	Wheel and brake caliper removed. Arrow shows location of Phillips screw that holds rotor on hub.

The next phase of the procedure is the same as if you were replacing the brake rotors (for more detail see the 4.0/4.6 Brake Job page):

1. Jack up vehicle and insert axle stands.
2. Remove wheel.
3. Remove brake caliper.
4. Unscrew the Phillips screw holding the rotor on (see photo above right) and remove rotor.
5. Remove 3 bolts securing rotor mud shield (8mm wrench); remove mud shield.
6. Using a pair of strong pliers or similar, pull the ABS sensor out of its hole in the top of the hub assembly (it is just held in by friction -- see photo below in "replacement" section).
7. Undo the 6 bolts (13mm) securing the hub assembly to the axle housing.
8. Withdraw the hub and axle as a unit.

The above is the gospel according to the shop manual; I found that on step 5 the theory and the facts started diverging sharply. The heat generated by the bearing failure had evidently welded or frozen the rotor on pretty solidly, and it would not come off, even under vigorous coaxing. With the rotor still on, it is impossible to remove the mud shield, so I left both in place, performed steps 6 and 7, then withdrew the whole assembly of hub, axle, rotor and mud shield -- see photo below left. I figured I would have a better chance of getting the rotor off when the whole gubbins was out in plain view. As indicated in the photos below, I sat the hub on the ground and bashed the exposed part of the rotor with a sledge hammer while rotating the mud shield and hub to different positions. The rotor soon succumbed to this gentle persuasion and I was able to separate the various parts to rescue the ones I intended to re-use (i.e., the rotor, mud shield, and axle).

Hub & axle removed with brake rotor and mud shield still on. Resting hub on wheel studs facilitates applying force to rotor.	A few blows with the sledge soon got the rotor off, allowing disassembly to proceed.	Axle shaft removed, showing splined section and ABS reluctor teeth.

With the parts all removed, the full extent of the damage is now visible. In my case it was not a pretty sight -- the photos below show that the two halves of the hub assembly had separated and it appeared that the outer tapered bearing had completely disintegrated, i.e., had been chewed up and spat out!! This accounted for the large amount of metal swarf everywhere including inside the wheel and on the the mud shield, caliper, etc., etc.

Old hub after removing rotor and mud shield but before removing axle, protruding at rear.	Two halves of old hub showing inner bearing still in place (right arrow) and position of outer bearing (left arrow) from which the rollers have disappeared -- only its inside race is still there!! Note metal filings -- evidence of parts that were chewed up!! Also note the outer bearing race (in which both bearings are supposed to run) is still in the bearing housing at right.

The final disassembly step is to remove the oil seal at the end of the axle housing that stops oil from sloshing out of the housing on to the street. (Fortunately the standard oil level in the diff is low enough to not spill out when you remove the seal). Removal requires applying some leverage with something strong like a small pry bar (see photos below). I had been hoping that failure of this seal was all that was wrong with my hub, but this turned out to be one of my most optimistic dreams! Instead the bearings were destroyed as described above, and the seal was amazingly intact!! It must have let some oil past with the axle floating around, but not much, as the diff was still full.

Oil seal still in place.	End of axle housing with oil seal removed.

Replacement and Reassembly

Before replacing any of the parts, remove any iron filings left over from the bearing destruction process. Otherwise these could infiltrate the new bearings or the diff and destroy them, too. It might be worth taking a peek inside the axle housing to see if the iron filings and debris are evident in there -- if so, it might also be worth trying to get them out of the axle and diff housing! In my case, it looked as if the relatively intact oil seal had prevented the worst of the debris from getting past into the housing, but I cleaned it out anyhow with a rag on a stick.

The photo below at left shows the "new" hub assembly ready to be installed (suffering from impoverishment, I replaced mine with a used one for I got from the wreckers for $150, so it does not look entirely pristine!!).

"New" hub ready to be put on. Wheel studs at bottom of picture. Hole for ABS sensor is at top right.	"New" hub installed. Note ABS sensor re-inserted at top left.

Reassembly procedure:

1. Push the new oil seal into place on the end of the axle housing (I found this needed some force but was just possible by hand).
2. Insert the axle into the hub and tighten the nut finger tight.
3. Insert the hub and axle, engaging the splines into the diff. Attach hub to axle housing with the six 13mm bolts.
4. Reinsert the ABS sensor.
5. Reattach mud shield.
6. Reattach brake rotor.
7. Reattach caliper and pads.
8. Put wheel back on, remove safety axle stands and lower jack.
9. Check oil level in diff.
   

   In step 4, the shop manual dictates replacing the $35 adapter (a springy friction fitting) with associated rubber collar that houses the ABS sensor and holds it in place in the hub. I ignored this advice, but if the sensor seems to be too loose in the hub, you could try removing the adapter and bending it to make the fit a bit tighter.

10. Done!!

Procedure for Replacing Bearings Only (Keeping Original Hub)

First, the two halves of the hub need to be pressed apart to access the bearing assembly (see photo below). Scott used a 20 ton press and an acetylene torch to heat up and expand the outer part. "We ended up bending the steel frame of the press because we had to use so much pressure. In fact, it took almost 30 minutes of heating and cooling while the hub was being subjected to 20 tons of pressure before it finally exploded apart". (Joe Godfrey says Loktite is used during assembly, and when the bearing fails it cooks, making removal more difficult).

Exploded view of hub &bearing assembly pressed apart (this is a front hub, courtesy of Lori Sickley). At left is the hub with the wheel studs on it; at right is the bearing housing that attaches to the axle case. At center is the bearing race, which has to be pressed out of the bearing carrier, and the two tapered roller bearings removed from the race. They are assembled with the narrow sides inward together, and the left one is held in palce by a snap ring, also shown removed.

View of the outer bearing race with bearings removed from it -- one of the bearings is on the left. Both photos courtesy of Lori Sickley.	New bearing assemby with the two bearings already mounted in the outer race.

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