design - Land Rover section


Land Rover tips


This section consists of a number of little articles to share things that I have learned over the years. These are my personal opinions based upon my experiences. They are not necessarily "ABSOLUTE FACTS"





Axle breathers are designed to vent excess pressure while keeping water from entering the axle housing. The old style breather that came on our Series Land Rovers is essentially a caged ball resting on an opening. Internal pressure lifts the ball and vents. Gravity is supposed to keep water out while the Series Land Rover is wading.  Oil spray coats the metal ball in the old style breather causing it to adhere to the opening. When this happens the pressure builds up and forces 90 wt out of the land Rover's pinion seal.  Most pinion seal leaks on old Land Rovers can be cured by replacing old style breathers with the newer Series Land Rover remote breather (Defender style).  The newer style Series Land Rover remote breather consists of an open tube routed into a protected space inside the frame or high above wading level. An open tube vents any pressure build up.

When I switched to Defender style remote breathers my pinion seal leaks stopped immediately. The insides of my diffs are not taking on water as much as they used to while deep wading.   On Land Rover Defenders the rear breather hose is routed along the axle housing and frame following the brake line. The end tucks into a hole along the side of the frame. I have read of some people drilling a hole in their body and routing the tube up into the rear tool box.

The front Defender style breather goes up vertically. In the Series Land Rover, you can put a little 'C' curve into the tube for flex and jam it into the corner space between the rear of the radiator and the shroud. Under frequent extreme articulation and vibration, the hose doesn't last long in this location. I prefer using a rear breather on the front. The hose comes out the side and is longer. It can be routed up alongside the inner wing and held up by a couple of clamps that are large enough that the tube slides inside them. This keeps the tubing away from the fan and provides additional slack for movement.

Land Rover Defender breathers are metric and will not screw into the breather hole in your Series Land Rover axle housing.  What you need is the Series Land Rover remote breather, Land Rover part number 595473.

These breathers can also be added to the tops of the transmission, transfer case and overdrive to prevent pressure buildup from pushing 90 wt out the seals. The tubing can be routed up over the transmission and up the firewall.  The top rear of the Series Land Rover gearbox has a small rectangular plate with a small hole.  That small hole is the breather hole for both the Series Land Rover's gearbox and transfercase. It can benefit from having a tube type remote breather added.   That's really all you need for both the gearbox and transfer case.  If the transfercase was assembled by someone who clogged the transfercase breather passageway with RTV you can add a remote breather to one of the two steel top plates on the transfercase.  It doesn't matter which plate gets the breather, and if the internal breather passage is open you don't need to add one on the transfercase after adding one on the gearbox. 

Both steel plates on a Series Land Rover transfer case sit directly over gears that rotate into a pool of oil,  They throw oil at the top of the transfercase plate with a lot of force.  If you decide to add a breather to one of the metal plates I recommend braising a deflector shield to the bottom of the plate .

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Engine Mounts

People tend not to think of engine mounts until they are rebuilding the engine or until they separate miles from nowhere on a rough trail. An engine mount is basically a rectangular block of hard rubber with a plate of steel adhering to each end. When the rubber softens or the rubber metal boundary tries to shear one too many times, the mount will come apart. I have seen too many people dealing with lose engines in rough terrain. I even got to do it once myself.

I always check the engine mounts before leaving on a major trip. I visually inspect the rubber for swelling or major cracks. I check to see that the fixings holding them in place are tight and in good shape. It is common for one mount to break before the others.

A broken mount allows the engine and transmission to flex more placing additional strain on the remaining three mounts. I place a floor jack under the engine and lift the engine slightly to check the see if the metal plates are still adhering to the rubber. I repeat this at the transmission.

Diesel engine mounts fit petrol engines and are stronger than the petrol version. The metal plates on the petrol engine mounts are flat. The plates on the diesel mounts are channel shaped providing shear protection on one horizontal axis. I have diesel engine mounts under the engine and the transmission. I have them mounted so that the shear protection is front to back.

The engine mounts attach to metal brackets bolted to the side of the engine. The bracket on the right side came from the factory with with lock tabs. I had lock washers on my right side mount after an engine rebuild. On a very long section of severe wash boarding one of the torqued down mounting bolts with lock washer worked its way off. The steel bracket swiveled around the remaining bolt shearing both front engine mounts.

I suggest that you use the original style lock tabs. Also Locktite would be indicated for this use. Another option is to get bolts with drilled heads and safety wire them together. You DID replace the safety wires on the bolts in the right side of the engine block last time it was rebuilt didn't you?

A couple of engine mounts are a good item to keep in your travel spares kit.

When the threaded rod is welded to the flat steel face of the engine mount there is usually some "flash" left that shows up as little bumps on the flat surface. When you bolt a new mount to the engine, these bumps keep the flat surfaces from contacting each other. Over time and use, these bumps can be flattened causing space for engine mount movement to occur. This will shorten the life of your engine mounts. Before installing new engine mounts, file off any bumps on the mating surfaces to assure a tight mounting.

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Strengthening a Rover differential (Information provided by Bill Davis of Great Basin Rovers in a mendo list discussion)

When we rebuild Series differentials we discard about 90% of the ring& pinion sets as unusable. Surprisingly, the bulk of these are because they are because they are rusted and pitted. You need to remember that for many years old Land Rovers were in many cases neglected utility vehicles, that were not regularly serviced or even used. Also the axle case breathers in early Land Rovers were not very good and often plugged. Between water ingress and condensation, these diff frequently have a surprisingly large amount of water in them. If you don't use the vehicles regularly, the water settles out on the bottom of the diff and guess what it is sitting in? The bottom of the ring gear for the folks that guessed wrong. So a useful Series tech tip is to convert to the extended axle case breathers, they are worth their weight in gold.

Series diffs do have some issues though. The majors ones are that the ring gear bolts are garbage and the issue is compounded by a very poor design of the ring gear bolts lockers. They are mild steel and compress over time which releases the torque on them. They also correctly shouldered only two of the ring gear bolts hence putting excessive stress on them under hard usage especially when the mild steel bolt lockers have released the torque. The result is that the two properly shouldered ones break, which allows movement in the ring gear, which eventually results in the other 8 breaking. Land Rover actually solved this problem in late 1980 when they released the 4.7UNF gears. Unfortunately when they consolidated the parts book they eliminated them and superseded everything back to earlier inferior BS design. The MBA's get revenge again.

This issue is actually easy to 50% solve. Get rid of the mild steel bolt lockers, replace them with grade 8 washers and Lock-Tite the ring gear bolts with the red stuff. Also make sure you mount the two ring gear bolts with the larger shoulders opposite of each other. Another easy thing to do is replace the other 8 ring gear bolts with the ones with bigger shoulders. Unfortunately LR doesn't supply them any more. Those darn MBA's again. I'm actually trying to persuade ARP Racing to make me a custom run of proper LR ring gear bolts but nothing definitive yet.

You do NOT need to disassemble your differential to do this upgrade so it is quite easy. You do need to obviously remove the diff from the axle housing but when it is out you can replace the ring gear bolts individually one at a time. Procedure is as follows:

0) Source 10 7/16th grade 8 washers.  Make sure they are grade 8. You might need to go to a specialty nut & bolt supply joint since most of the stuff at general hardware places is grade 5. Usually the grade 8 stuff is cadmium coated (gold) not zinc coated (silver). You can also use genuine LR hardened washers (Land Rover part number for 593693) but they are expensive, about $1.50 each. Hardened is hardened.

1) Bend stock ring gear bolt locker back to allow access to the ring gear bolt.

2) Remove a ring gear bolt

3) Bend the bolt locker out of the way or trim it away with tin snips.

4) Thoroughly clean the threads of both the bolt and ring gear with brake parts cleaner to make sure the Lock-Tite is effective. Compressed air helps with this.

5) Use permanent thread locker (usually the red stuff) and apply it liberally to the threads, and install the ring bolt with the new hardened washer and torque to 45 ft/lbs. Do not over do the torque.

6) Repeat for the remaining 9 ring gear bolts.

Two more pointers, first if you ever need to remove the now chemically thread locked apply some heat first to to soften it up to avoid breaking the bolts. Properly installed, thread locker is very very effective. Second, check to make sure the special shouldered bolts are opposite of each other. This is actually fairly easy to do without resorting to using a micrometer. The special bolts are usually silver and the other 8 are dark grey/black. Check this out before you thread lock everything! Doing this will eliminate one of the most common reasons why Series diffs fail prematurely and catastrophically. This tech tip also applies to early Range Rover Classics between 1970 and 1980.


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Keeping the engine from going forward

You may not notice your engine mounts breaking until all four have sheared. When this happens, the engine tends to shift forward putting the fan into the radiator core.

Military Land Rovers commonly have a mechanical restraint that keeps the engine from shifting forward if all the mounts break. It is fairly easy to install a similar restraint into a civilian spec Land Rover.

There are two flanges at the bottom of the bell housing where it mates with the transmission. One of these flanges secures the bottom of the hi-low range shift lever. The other is unused.

Mount an eye bolt into the hole in the unused flange with a nut on each side of the flange to position the eye bolt. Directly behind the eye bolt., drill a hole through the transmission cross member and install a second eye bolt. so that the eyes are facing each other.

Next install a section of chain between the two eye bolts. Adjust the eye bolts. until there is just a little slack in the chain. If you experience a catastrophic failure of all four engine mounts the engine will be stopped from sliding forward by the chain.

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Distributor protection

The most common cause of petrol engines dying while fording a body of water is the distributor getting wet. There are a few things that you can do to help the insides of your distributor stay dry.

The easiest is to cover the front of the radiator before starting to ford a body of water. A radiator muff, sheet of canvas or plastic will keep a bow wave from entering the radiator and getting flown back by the radiator fan.

This will not be of much help if the car reaches a depth where the bottom of the fan reaches water level. Your first protection is the splash shield that fits over the top of the fan. It keeps a lot of the water from flying about in the engine compartment. The splash shield can be modified to protect the distributor. There is an arm of the splash shield that reaches towards the distributor. The end can be bent down towards the engine. A thick sheet of rubber can be bolted to the turned down flange providing a physical barrier between the fan and the distributor.

Another help is to smear a thin barrier of petroleum jelly along the seam between the distributor cap and body then wrapping the seam with electrical tape. This is best done just prior to fording and removed afterwards as the inside of the distributor needs to "breathe".

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Vibration and bonnets

Bonnets on civilian Land Rovers are attached at the back by two hinges and at the front by a single spring loaded latch. The spring pressure on the latch tends to keep the bonnet from resting securely on the radiator bulkhead. The civilian style bonnet spare tyre mount holds the spare securely in place at the center of the rim.

If you observe a civilian bonnet while driving down a severely washboard road you will see that the front end of the bonnet tends to vibrate side to side. The bonnet mounted spare vibrates on its center mount as well.

Frequent driving on severe washboard surfaces will eventually fatigue the aluminum bonnet creating stress cracks at the hinges and along the edge of the bonnet tyre mount.

The military version of the Land Rover has a spring loaded draw latch at each front corner. This pulls the bonnet down against the radiator bulkhead and minimizes bonnet vibration.

The military version of the Land Rover also has a three way strap lashing the spare tyre to the bonnet. This tends to inhibit tyre vibration.

These are easy to add on to a civilian Land Rover and provides the car with vibration protection.

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Vibration and rear work lamps

Rear mounted work lamps have become a very popular Land Rover accessory. They make camping and evening work easier and more comfortable. Unfortunately, to the body of your car, the work light looks like a weight at the end of a hard metal lever.

When driving on uneven surfaces the rear lamp will vibrate. It will be the soft aluminum body that will flex, not the steel mount. On sever wash board surfaces stress cracks can appear in the aluminum body of your car around the edge of the steel mounting bracket in just a few hours.

One way to radically slow this process down is to thicken the car's body where the lamp bracket is mounted. A common solution is to glue and bolt a thicker aluminum plate behind the body where the lamp is mounted to minimize body flex. I mounted a sheet of aluminum on each side of the lamp mount. I secured the sheets of aluminum with both adhesive and bolts so that the pieces would act as a single thickness.

Another way to address this problem to to keep the lamp from vibrating. For instance you can tie a cord between the work lamp handle and something on the body above the lamp and pull it tight enough to add a little tension before driving rough surfaces.

My Hi lift jack is mounted vertically just below my work lamp. I added a support on the mounting bracket that rides on the top end of the jack.

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Vibration of tubing

When a metal tube vibrates it places the greatest amount of stress at it's stationary connections. Stress cracks normally appear at these connectors on the ends of the metal tubing.

Metal tubing should be routed along the surface of the body or frame and frequently anchored to keep them from vibrating. When Rover routes a steel tube across an unsupported area they tend to anchor the unsupported tubing with rubber clamps.

An example of this is the brake tubing along the rear axles. Rover utilized two rubber clamps to dampen vibration.

If you are routing tubing, I recommend that you follow the same practices that Rover used routing your brake lines.

Since vacuum advance lines tend to have long unsupported lengths, I highly recommend that vacuum advance tubing be rubber. Copper vacuum advance lines break very quickly when subjected to intense vibration.

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Field repair of coolant hoses

I always try to stress going over your car before going out on expedition to prevent problems instead of fixing them. Soft swollen hoses are easy to spot and replace before they go bad.

So this fix is for the poor guy you meet on the trail who didn't do a pre-trip inspection and has blown a coolant hose. You can make an effective field repair by drying off the hose, wrapping it in several layers of duct tape then tightening three hose clamps over the duct taped rupture point. After the radiator is refilled, leave the radiator cap loose to keep pressure from building up.

Something that I have not tried but have been told (so it may or may not be real) is that a small radiator leak can be stopped with mustard. It goes inside the radiator. I wonder if you should add relish for larger leaks?

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Stuff placed on series II instrument panels

The tops of series II instrument panels seem to be a good place to stash things you use when driving. I keep sun glasses, gum, sunscreen and other odds and ends on top of mine.

This works fine until you park on a side slant and the stuff falls out of the car when you open the door.

To solve this problem, I cut a small sheet of aluminum to fit on the end of the capping and pop riveted it into place. Now the stuff I place on top of the instrument panel stays there.

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Thoughts about replacing leaf springs on left hand drive Land Rovers

The Series Land Rover was originally designed for the home (right hand drive) market. A right hand drive Series Land Rover 88 or 109 regular has the weight of the driver, front fuel tank and battery all on the right hand side of the Land Rover.

Assuming a full fuel tank, that's about 150 pounds, plus the driver's weight there is around 300 or more extra pounds on the right side of a RHD Series Land Rover. Rover designed the springs to compensate for this extra right side weight so that the car would ride level when driven.

On a left hand drive Series Land Rover, you have the driver on the left side counter balancing the fuel tank and battery. If you have a second front tank installed then the weights of your tanks are balancing each other out. Left hand drive Series Land Rovers often list after new springs are installed per the factory recommendations.

I recommend that left hand drive Series Land Rovers be fitted with the same spring type on both sides since it does not have the intrinsic weight imbalance that a right hand drive Series Land Rover does.

You can tune your suspension to your liking by choosing which springs you want to use. For instance, the "passenger side" spring is one step softer than the "driver side" spring and will cause the car to sit just a little lower with a given amount of weight. So if a softer ride is desirable and ground clearance is not critical you can install two "passenger side" springs at each end of the car. Conversely, if you are carrying a heavier load than stock, or want more clearance and harshness of ride is secondary to the clearance you might want to install a set of driver's side springs or step up to the next stronger level of springs.

When Rover fitted a winch from the factory they fitted the next heavier duty spring set on the front of the car. For an 88 they fitted standard 109 front springs. For a 109 they fitted 109 1 ton front springs.

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