All the gear
ONE of the best things about owning an older Land Rover, in my opinion, is the huge range of parts and accessories available to customise or modify the vehicle to suit an individual owner’s needs. From heated seats to four-inch lift kits, just about every part of an old Land Rover can be upgraded or modified. I absolutely adore original unmolested timewarp vehicles, but sometimes I look at some of the vehicles that my customers bring me and wish I owned an old Defender 90 with the full off-road treatment, big tyres, front and rear winches, rollcage, the lot.
As we all know, a standard Defender on half-decent tyres offers pretty awesome off-road performance in showroom trim. Land Rover’s engineers really knew what they were doing, and the vehicles that rolled out of Solihull were (with very few exceptions) a well-rounded package in which the balance between on-road and off-road ability was just about perfect for most users. When you carry out mechanical modifications to the vehicle this does not always make it better, it just tilts the balance in one direction or another.
High-ratio transfer boxes are a good example of this. The standard box on most Defenders is 1.410 ratio which will allow a slightly noisy but not too frantic 70 mph cruising speed. The Discovery 1 transfer box is 1.2 ratio and a straight swap, so quite a few people have fitted Discovery transfer boxes to Defenders. I have done a few myself. It makes for more relaxed cruising, but the downside is significantly less lively acceleration: on 1.2 gearing you have to work the engine quite hard through the gears to make significant progress. And with anything less than a Tdi under the bonnet, forget the whole idea: I once drove a non-turbo diesel engined Ninety on 1.2 gearing, and fifth gear was barely usable unless going downhill.
Suspension modifications are an area where it is very easy to make a vehicle worse. Yes, a four-inch lift looks cool, but the leading arm suspension used on Defenders (I suppose we should now say Defender 1, since there is a new one out) is a very primitive system and the geometry is horrible by modern standards. As you raise the vehicle on its springs, the caster angle reduces. Imagine a vertical line drawn through the centre of each front wheel, and a second line through the upper and lower suspension swivels. This second line should be slightly laid backwards from the vertical – that is your caster angle, and as it reduces towards zero the steering loses its self-centering action and the vehicle becomes very twitchy and hard to keep in a straight line. Even a fairly modest lift makes a difference.
All the parts you need to correct the geometry are available to buy, and it is important to do your research and understand that the suspension system on a Land Rover is a complete package in which all the elements must be considered. It’s not just about longer springs and shocks. Bear in mind also that by fitting a lift kit you are raising the centre of gravity so that the vehicle will tend to roll more on bends. By making the vehicle more capable off-road you will be making it significantly less capable on-road. I have driven a few modified Defenders which were unstable to the point of being plain dangerous on anything other than a wide, flat, straight road.
All of which brings me to this month’s Norfolk Garage victim, an older ex-army Ninety which had been fitted with a Discovery 200Tdi engine and given the full off-road monster treatment. It stood tall and proud on big chunky mud terrain tyres, and everyone who saw it said 'nice truck'. It had recently changed hands: the new owner was unhappy with the brakes and had a list of other niggles for me to attend to, which included finishing off the 200Tdi conversion. It was a neat job, but whoever did it had obviously lost enthusiasm towards the end as it lacked any kind of air filter.
A quick look underneath revealed almost new springs and shocks from a reputable supplier, and the all-important caster-correcting front radius arms and cranked trailing arms (not as critical as the fronts, but they give the chassis bushes a much easier time). There was a wide-angle front propshaft, sensible underbody protection and a shiny new steering box and drop arm. The owner parked the vehicle up at the front of the workshop, and a couple of hours later I needed to move it so that I could get another vehicle out. I fired it up, drove it from one end of the yard to the other which
was frankly quite far enough. It was horrible. Almost no brakes, lots of steering play, exhaust rattling on the chassis, loads of backlash in the transmission, and a horrible shudder and clanking noise when reversing. I clearly had some work to do. The first job was to attend to the brakes and I started at the back. This Ninety was a pre-1993 example with its original back axle, which meant ten-inch drum brakes. You can take a good guess at what you will find inside the drums by seeing how easy they are to remove. On a well-maintained vehicle the drums will usually come off with a couple of smacks on the front face to bounce them off the hub. If that fails you can bet the drums haven’t been off in a while. There is a threaded hole in the face of the drum: if you screw a bolt of appropriate size into the hole it will break the rust join between hub and drum. The drums on this vehicle put up quite a fight, and on finally removing them it was easy to see why – the shoes were worn down to the metal and had cut deep grooves in the drums. Off-roading in water tends to fill the drums with dust and dirt which wears the shoes quite rapidly, but that is no excuse for this kind of neglect. One of the wheel cylinders was leaking and the other looked old and corroded so I ended up changing the lot – shoes, drums and cylinders. Parts for these old drum brakes are cheap and easy enough to fit. I had a strong suspicion as to the cause of the clanking and juddering. Off with the rear propshaft and transmission brake drum to reveal more brake shoes worn down to the limit and a thick layer of sticky gunge inside the drum. Some brake cleaner and a new set of shoes had the handbrake working properly without binding. It is a shame that whoever fitted the brand-new rear propshaft did not take the opportunity to pull the handbrake drum off and have a look inside. Due to the need to remove the propshaft, Defender transmission brakes tend to be neglected until they are bad enough to fail an MOT test. I refitted the rear propshaft and then noticed some play in the drive flange on the rear differential. The securing nut was tight which ruled out one cause. On most Rover differentials the pinion is supported on two taper roller bearings with a rigid spacer and shims between them. The bearing preload can be adjusted by changing the shims for thicker or thinner ones. I extracted the outermost bearing and found it had chunks missing from the rollers where the case hardening had broken up. No problem, I had a spare 3.54 ratio ten-spline differential in good order, and changing the rear differential on a Defender is a piece of cake. I drained the oil (sludgy and water-contaminated), pulled the rear halfshafts and found they had 24 spline inner ends, which puzzled me, as the drive flange on the differential was the older four-spline pattern. All became clear when I removed the differential from the axle casing. It turned out to be a fairly rare four-pin unit from a factory V8 Ninety, sadly with rust pitting on the gear teeth.
I had a 24-spline differential (albeit not a four-pin one) from a Discovery 300Tdi, and after checking that the V8 halfshaft ends were the same as the Discovery ones I cleaned up the casing, applied a bead of RTV sealant and heaved the big, heavy differential up into position. It was at this point I found that Discovery 24-spline differentials have a beefed-up casing flange compared to old V8 ones, so four of the studs were too short to get a nut onto them. I locked up the workshop and went home in a foul temper.
Next day, it was on to Plan C. I had a complete rear axle from a Discovery 200Tdi laying outside, which I thought would yield a pair of ten-spline halfshafts to go with my spare ten-spline differential, which I knew would fit the Ninety axle casing. I started work nice and early, got the axle onto some stands, drained the oil, undid the halfshaft flange bolts with my nice new cordless impact gun (which works remarkably well for something that has 'CHAERGR' printed in large letters on the battery charger), pulled a halfshaft and found it had a 24-spline inner end. Late Discovery 200Tdis had 300Tdi axles, as I now know. I carried on stripping the axle just to get it out of the way (it had a badly-rusted casing) and was soon surrounded with oily lumps of metal and no further forward with the Ninety. I was about ready to give up Land Rover spannering and become a florist, when it occurred to me that I now had a full set of long studs. All I had to do was swap four of them for the short ones in the Ninety casing. The studs are of the splined pull-through type and easily changed.
Onwards and upwards: after sorting out the rattly exhaust I turned my attention to the front end of the vehicle. The drive flange on the front differential was even more waggly than the rear, which provoked another torrent of bad language. I removed the front propshaft and found that some fool had left out the large washer which goes underneath the drive flange nut – no split pin on the nut either. With that little problem swiftly sorted I started investigating the front brakes: one pad not just down to the backing metal, but ground away to about half its original thickness. The pistons were very close to popping out of the caliper. Needless to say the brake discs were scrap. How long since this poor old Ninety had actually been
serviced? Possibly not since the Army had finished with it.
One of the wheel bearings was rumbling quite badly so I removed the hub to find that the inner bearing was seized solid with rust. I didn’t even bother trying to separate it from the stub axle. I had a complete set of Discovery 200Tdi front axle components including a pair of hubs with brand-new brake discs, so I just swapped over the lot. The Ninety front halfshafts and drive flanges were on their last legs, which accounted for at least some of the transmission backlash I had noticed. The brake caliper pistons were all badly corroded at the outer ends and were replaced with new.
The last mechanical job was the simplest. With the front wheels jacked up, I could see the new drop arm moving up and down on the shaft as I turned the wheels from lock to lock. The drop arm is on a splined, tapered shaft, secured with a very large nut done up very tight (130 lb ft). My ¾” drive socket set makes short work of these. With the vehicle back on its wheels I drove it up the yard again and it was transformed. Moral: before you start spending money on shiny off-road kit, make sure you get the basics right. The best suspension in the world won’t be a lot of use to you when you’ve broken down miles from anywhere due to simple lack of maintenance.