Removing the old hub assembly
Safety first
The Discovery
1 must be safely raised on axle stands or on a vehicle ramp (lift) for the job. The road wheel is then removed to get at the hub.
LIKE many jobs on a Land Rover, much time is spent removing associated parts to get at the component that needs to be replaced. In the case of the Discovery wheel bearing hub assembly, the wheel, brake caliper, brake pads and brake disc all need to be removed to get at the hub assembly. It also helps to remove the brake shield.
When removing a series of parts like this, it pays dividends to be organised and methodical. Take note of the order in which things come off, including fixing bolts, so that it is easy to reverse the process when rebuilding – this way you can make sure that everything is refitted correctly. This is very important for safety related systems, such as brakes.
Removing the old hub assembly is straight forward and no specialist tools are needed, save for a gear/hub puller if the drive shaft is stuck in the hub.
I used heat from a blowtorch to help loosen some of the fixing bolts. Should you decide to follow this method, take very great care where the flame is pointed and for how long – it is easy to cause damage to other components in close proximity and, worse, a fire could be started!
Time to dig down
After removing the road wheel, the
2 brake caliper is moved out of the way by removing the two mounting bolts, which are loosened with a 12 mm socket wrench.
Keep the fluid in
The caliper is left attached to the
3 hydraulic system and simply tied securely out of the way, so that there is no strain on the flexible hose.
Keep them in the right order
The brake pads are lifted off now and 4 are set aside, ensuring that they can be re-fitted to the brake disc exactly in their original positions.
Rust can make them round
The two bolts that hold the brake caliper 5 carrier are bi-hexagon (12-sided). The heads on these bolts are in good condition, as they were recently replaced.
The correct tool is required
A bi-hex socket wrench is needed to 6 remove the bolts, which are in a fairly tight spot but, with the steering cranked over, you can just see them.
Off its mountings
The ABS cable that runs from the
7 wheel bearing hub through to the engine bay is unclipped from the mounting point on the brake hose bracket.
Still in good shape
Very often these caliper bolts would 8 be replaced due to the condition of the head, but rust has not yet ruined the top of these bolts.
Do sprung sliders work okay?
The caliper carrier can now be lifted 9 off and its condition inspected, particularly the moving parts that can become seized with rust and dirt.
Use to correct size
Using a big Pozi-drive number 4 10 screwdriver, the countersunk screw that holds the brake disc is removed, unclipping it from each securing point.
A good brake rotor
The brake disc is withdrawn, and its 11 condition inspected. This one has very little wear, and no grooving or pitting, so does not need to be replaced.
Get it out in one piece
The three small flange bolts that 12 hold the brake shield are very prone to shearing off, but the application of some heat will help free them up.
Thankfully, it is turning
An 8 mm socket wrench is then used 13 to loosen the flange bolts. With the heat having done the trick, the bolts did not shear off in the threaded holes.
Round head
Where the bolt head has rusted and 14 become too small for an 8 mm socket, a nut extractor tool is used to turn the bolt and successfully remove it.
Gets it out of the way
The brake shield is now free and can 15 be withdrawn from the hub. While not essential to remove it, the job has been made a little easier.
Concealed bolt heads
The wheel bearing hub assembly is 16 now fully revealed, showing that it is held in place by four flange bolts that have their heads to the inside of the hub.
It really does help!
Carefully applying some localised heat 17 to the hub, around where the bolts are threaded into the assembly, makes the job of loosening them a little easier.
Find one that fits the space
The bolts are loosened using a 15 mm 18 socket wrench. As the work area is quite restricted, I found that a smaller 3/8 inch drive ratchet worked better for this job.
Last one
The fourth and final bolt is removed. 19
This time there was enough clearance to use a short extension bar, allowing a better arc for the wrench.
Lots of torque required
The large hub nut in the centre of 20 the wheel bearing hub assembly is removed using a 30 mm socket, in this case using an impact wrench.
It may not slide off easily
The drive shaft wanted to come out 21 as the hub assembly is withdrawn, which we don’t want, so a two-legged puller is used to pull the hub clear.
Disconnect and remove
Before removing the hub, the ABS 22 lead is unplugged in the engine bay and pushed out through the wheel arch, unclipping it from each securing point.
Fully stripped
The wheel bearing hub assembly has 23 now been fully removed, along with the ABS cable, having fed it through as the hub was taken off.
Find the correct path
The new ABS cable needs to be
24 routed through from the hub location to the engine bay in exactly the same way that the old one had been placed.
Shiny new and complete
The new replacement wheel bearing 25 hub assembly comes with a new ABS sensor and lead, which provides reliability to the system with the fresh components.
Fits like a glove
With the ABS cable correctly routed, 26 the new wheel bearing hub assembly is gently tapped in position in the knuckle, ready for the bolts to be fitted.
Firmly bolted
The four flange bolts are now back in 27 place and tightened to 100 Nm using a torque wrench. The brake shield has also been replaced.
Back on and secure
The brake disc can now be refitted 28 over the new hub assembly and the countersunk screw tightened back in place, using the number 4 Pozi-drive screwdriver.
Adding the brakes
As the build up continues, the brake 29 caliper carrier is next to be refitted using the original bolts, tightened with the 19 mm bi-hex socket wrench.
Lots of life
The brake pads have plenty of wear 30 left in them and are refitted, making certain that they are the same way around as they were originally.
Untied and united
The brake caliper is undone from its 31 securing position and refitted to the carrier using the original bolts and tightened with a 12 mm socket wrench.
It is the best policy
A brand-new driveshaft nut should be 32 used as a matter of course, and the original one discarded – it’s important for safety. They are inexpensive.
Very tight indeed
The new driveshaft nut is fitted and 33 tightened to 490 Nm using an impact wrench initially, and then finally checked with a torque wrench.
This will keep it on
After the driveshaft nut is tightened, 34 it is ‘staked’ to the shaft using a punch or similar to bend the rim into the shaft’s groove, preventing it loosening.