P38 Hub and Wheel Bearing Replacement  

Introduction
Symptoms and Diagnosis
Parts Needed
Tools Needed
Removing the Hub
Replacing the Hub
Replacing Bearings Only (Keeping Old Hub)



Photo: Hub assembly view from rear or inside end with wheel studs pointing away from camera. Axle half shaft at top right. 


Introduction
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.

Symptoms and Diagnosis
The symptoms that can indicate wheel bearing failure include:

• 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!!

Parts Needed
(See 4.0/4.6 parts sources page for more detail, and the  pictures in the instructions below for photos of the various parts).

Hub & Bearing Assembly:
The lowest prices I have seen for the hub assemblies (in which the bearings are included) are at Rovers North, which has the rear hub assembly (FTC3223) for $466, the front left (FTC3243) for $469, and the front right (FTC3226) for $499. See photo at top of page for appearance of the hub assembly (rear one).

Bearings and Outer Race Assembly Only:
Atlantic British now has a less expensive solution -- they can sell you the bearings and outer race only (part number FTC1507) for $199 (front or rear). It is also available from various suppliers in the UK for about 80 to 95 pounds sterling. This assembly looks like the photo below at left -- courtesy of Lori Sickley, who got hers from Kaid Ltd in the UK for about £80 ($150) each plus shipping, which was about £35 for two. These bearings seem like the least expensive "officially sanctioned" option other than finding the right generic parts (see below). They include the 2 tapered roller bearings, inner and outer, prepacked into the outer bearing race, pre-greased. You need a means (usually an hydraulic press) for pressing the old bearing assembly out of the hub and pressing in the new one. A torch to heat up the outer housing is also a help.

Bearings Only (Generic Parts): The bearings only, without the race, can be seen in the photo above at right. There is an inner and outer bearing (both the same, and front and rear use the same bearings). When replacing my right rear hub assembly, I found the inner bearing was a Timken unit inscribed with part number NP275832. It also had a "DV" symbol on its, and was made in France.  Warning: if you do go the generic bearing route, make sure your outer bearing race is still in good shape!!

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.

Axle Seal

The oil seal on the axle (FTC5209), available at any Land Rover dealer or parts supplier for $16 or less, should be replaced at the same time "whether it needs it or not".

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.

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).

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.

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.

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!!).

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)
As mentioned earlier, if you are fortunate enough (unlike me) to catch the problem before disintegration occurs, and you have the right equipment (including at least a 20 ton hydraulic press -- 50 or 100 tons is better), you can replace the actual bearings only, keeping the hub housing.  Scott Kirn did this operation using the bearings and outer race package sold by Atlantic British.  He found the kit included the 2 bearings, inner and outer, prepacked into the bearing race. It is also pre-greased. You need the hydraulic press to press out the old bearings and press in the new ones.

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).

After getting the two halves of  the hub apart, there is a certain amount of randomness in which parts will remain stuck to what. Most likely, the outer bearing race with the inner bearing still inside it will be stuck to the bearing housing (the right hand component in the photo above). This was the case when Scott Kirn did the operation. He reports "We then had to use a very large socket to press down on the center of the bearing to press that (and the race) out of the housing. If I remember correctly, that was the most difficult part, and the part that led to us bending the press. We kept heating it with the torch, then spraying it with water while the press was constantly on it. When it finally went, the bearing and everything literally exploded out like a cannon. Needless to say, one should use eye protection! Because of all the heat we used, it was impossible to tell the condition of the bearing once it was out - it was pretty much demolished.

The outer bearing is likely to still be stuck to the "spindle" half of the hub. After the rollers are pried off or otherwise removed, the inside race of this bearing is still stuck firmly on. This is the part at the head of the left hand arrow arrow in this photo above of the two halves of my own demolished hub from which the rollers on this bearing had conveniently disappeared through a process of self-destruction. This remnant cannot be removed with a hydraulic press, so Scott used an air grinder to carefully cut the race so it could then be air chiseled off the "spindle". You have to be careful to cut only the race itself, and not the spindle part of the hub.

Scott used the bearing kits from Atlantic British (see Parts section above), 1 for each front wheel. The bearings (see photo above right) came shrink wrapped in plastic, and already lubricated. You do not have to pack the bearings with grease. "You simply press the whole bearing into the hub housing, and that's it. It went very smoothly, no problems at all. In fact, re-assembly of the hubs was very easy."

Other Owners's Experiences:
Mark Kelly reports he has never managed to press the bearings out without damaging the hub. He says they are in there pretty tight -- it takes about 15-20 tonnes or so to shift them. Lori Sickley successfully performed the operation and kindly supplied the photos above. Nick Ground, who off roads frequently (presumably involving fording water)  found his bearings all failed between 116,000 and 136,000 miles on his 1998 Vogue. He only got 20-23,000 miles out of the replacement bearings, but it was unclear whether they replaced the complete bearing assembly including the outer bearing races which may have been worn.

Seamus from Ireland reports he found that disassembly and reassembly can be greatly helped with heat and cold. He advises putting the hub in the freezer for 3 to 4 hours, then using acetylene to heat the outer casing before applying pressure. "It still takes a good push but is slightly easer to do. When you get this far just cut off the rest of  the bearing with grinder. For reassembly, put bearing and inner half of hub in freezer for 2 to 3 hours then heat outer casing. Take bearing and press in -- the heat from the outer casing will have heated up the bearing so the inner part of hub should slip in resulting in a lot less pressure all round."