Protect your Defender’s underbelly with armour for rough off-roading. Martin Domoney of Land Rover Owners magazine explains how...
If you plan to use your Land Rover on rough terrain where rocks and other solid obstructions are present, it’s a good idea to invest in some extra protection. Bashing the weak differential casing on a stump or boulder can not only end your day out prematurely, but also result in an expensive repair bill.
We’re going to fit a wraparound front diff guard, allowing the axle to slide up and over obstacles due to its ramp-like design. Coupled with a reinforcing bash plate for the already tough rear Salisbury axle’s cover, they should give a sufficient level of protection for most off-road scenarios. At each end of the vehicle lie other vulnerable areas, with the steering arms and damper particularly exposed.
Fitting First Four Offroad's sleek, powder-coated 8mm thick Shadow steering guard will ward off damage. This well-designed guard fits tightly under the front bumper's edge, whether a standard or aftermarket part is fitted. The guard itself is extremely sturdy and surprisingly light. Finally, the fuel tank behind the rear axle is already afforded some protection in the form of a hefty adjustable towbar – but the tank itself is made of relatively thin steel.
A 4mm galvanised steel tank guard mounts on the original attachment points, and is capable of deflecting far more than the flimsy standard cradle, if it’s even fitted.
Copper avoids seizure
Smear bolts with copper grease before refitting to prevent them seizing in place, especially where fixings pass tightly through metal components or suspension bush sleeves. Be sure to clean extra grease off threads and use Loctite where necessary, though.
Clean and protect
It’s good practice to rectify small faults and nip any rust in the bud while carrying out unrelated work. A few minutes spent cleaning off surface rust or dried mud and treating the area can increase the longevity of the vehicle and make future jobs easier.
Prepare the axle
Starting with the front differential, give the whole area a good wire brushing and ensure no mud or stones will be trapped between guard and axle. Apply anti-corrosion paint/underseal and let it dry. Also, clear any packed-in mud from the diff drain and filler plugs.
Check the threads
Unbolt the track rod protector or steering damper mount, where the rear of the guard will fix to the diff. Use an appropriate-size tap to clean the threads; they often have rust or old threadlock inside. New, longer securing bolts are supplied with the diff guard.
Fit the bracket
Looking up at the top of the diff, the two 9⁄16in top nuts must be removed to allow fitment of the bracket. Once these are wound off, position the bracket and refit the nuts loosely. This will allow a degree of movement when lining up the main guard.
Bolt it up
With the top bracket in place, position the diff guard and start the nuts and bolts by hand. Once attached loosely, insert the track rod spacer between the diff housing and guard. Line it all up, ensuring the brackets are square with the diff. Tighten the bolts fully.
Prepare the diff
The rear diff guard is very simple to install; it uses the original diff cover mounting holes with longer bolts to attach over the pan. Wire-brush dirt and rust from the axle and apply paint if desired. Remove the six appropriate bolts and ensure holes are free from dirt.
Fit the guard
Position the guard on to the diff and tighten the bolts down gradually to 25lb ft. As with the front guard, the axle oil filler and drain bungs are still accessible with the guard in place for ease of servicing, so make sure they’re free of any caked-in dirt.
Remove the OEM bar
If fitted, the Defender’s standard tubular steering bar must be removed to install the steering guard. As seen here, this bar may offer a degree of protection, although this one has been fitted incorrectly, meaning it is too high and is in contact with the chassis rail.
Undo the bolts
Apply penetrating oil to the bolts ahead of time, and clean the threads as best you can to aid removal. They can be a pain to break free – the one holding the Panhard rod bracket can be especially tricky. Undo the nuts and knock the four bolts out.
Clean up the chassis rails
Offer up the side brackets and note where they make contact with the chassis. Once again, give the area a good wire-brushing and apply grease where the two surfaces will meet, in order to prevent water being trapped and setting off corrosion.
Bolt on the brackets
With the chassis rails prepared, push the bolts back through the holes and then hang the steel side brackets. Start the nuts and wind them on, but leave enough slack so that the brackets have a small amount of side-to-side movement.
Attach the plate
The main aluminium plate can now be offered up to the brackets. Allen screws will secure the part on to the side brackets; align the guard and nip these up before tightening the chassis bolts. The top edge of the guard should be parallel with the base of the bumper.
Tighten it up
With everything loosely in place, tighten the chassis bolts gradually so the guard sits level, then tighten them fully. Finally, tighten the four Allen bolts and nyloc nuts securing the main plate to the brackets. Torque the Panhard rod bracket bolt to 91lb ft.
Inspect the area
The galvanised steel fuel tank guard uses the original mounts for the tank; it can replace the corrosion-prone tank cradle. It’s important to inspect the mounting outriggers for rust/damage before fitting the guard, as it’s slightly heavier than the original.
Release the fixings
Remove the eight nuts and bolts, lower the anti-roll bar and remove the two towbar supports if fitted. Support the fuel tank with a stand or jack with a block of wood on top. Apply penetrating oil to the studs, and wind the nuts off. Don’t let the tank drop!
Position the guard
It’s difficult to get the guard in place without the tank dropping, so get some help. Drain fuel to make it more manageable if necessary. Slide the rear edge up first, as it sits inside the crossmember. With the guard located on the studs, support it in place.
Tighten the fixings
Ensure the rubber bushes and washers are fitted correctly and start the four nuts. Tighten them evenly to clamp everything squarely up to the chassis. Remove the floor jack and torque the fixings to 18lb ft. Finally, refit anti-roll bar and towbar brackets.
This article originally appeared in Land Rover Owners Magazine and has been reproduced with permission. Article is written by Land Rover expert Martin Domoney.