by other recognized official bodies,

but are non-the-less tried and tested methods.

If you feel that these methods are unsafe, then

consult other official bodies for an alternative method.

Always use correct axle stands and jacking/safety PPE

equipment before commencing work on/under any vehicle

POSTS YOU THINK NEED TO BE INDEXED IN THIS ARCHIVE PLEASE PM THE LINK TO ME --- Western,

then I can add it to the relevant section. 

*********************************************************************

Axles/Brakes

Discovery 2 - The Three Amigoes

need to know wheel offset, PCD or centre bore sizes

Disc brakes for Series Land Rovers

Longer wheel studs for defender

Axle removal/repair

Rover axle shaft specs

Rear Axle removal and repairs

Steering guard bolt size

DIY tracking

diff pinion seal 300TDI Discovery

Ultimate Diff protector

How a Diff works

Defender Handbrake sticking

RR or Discovery 1 handbrake lever fit to a 90 or 110 Defender [1983 to 2016 only]

Diff ratios

ARB info/Fitting/electrics/fitment list etc

ARB Solenoids

ABS diagnostics 1

ABS diagnostics 2

ABS Brake bleeding

Freelander ABS sensor replacement

Bodywork/Chassis etc

A guide to Defender bodyside graphics

How to fit forward facing seats in a pre-Puma 90

Defender 2nd Row seat box

Defender Door Repair Project

Defender door frame repair guide

Painting info for LR body panels

200/300TDI engine mounts/chassis mounting

Rangie/Discovery Sill replacement

RR rear floor and cross member replacement

Chassis dimensions

Aide to under bonnet cooling

Discovery cage/bumpers/protection

Discovery window regulator replacement

Discovery rear quarter panel removal

Discovery1 clock removal

Defender dash upgrade

Defender Bulkhead compatibility

Defender body capping replacement

Defender Crossmember upgrades

Bulkhead Galvanising and prep using a TD5 on early models

Defender 2 part split rear door

Discovery 1 inner wing repair

Replacing Station Wagon side windows

Discover window lift repair

Range Rover/Discovery wheel arch trimming

Side window fitting in a Defender

Defender Windscreen replacement

Disco 2A headlamp bulb upgrade/fix

Disco2 leaking sunroof

Defender fuel cap upgrade

Defender Body Removal

Aerocatch flush fitting bonnet pins

Greasable, slop free, rebuildable Defender door hinges

90 V8 fuel tank removal

Electrics

Mirror Switch Repair, D1,RRC,FrLand, FORD!! etc

"supercharging" your heater

Bad earth fault finding

Vehicle towing electrics, LR start on page 228.

Fitting Advanced Alternator Regulator to 300tdi

How does the Alternator power the battery?

Engine will not turn off? Fuel cut off solenoid stays on. How to fix.

10AS Pin Out

Discovery 300Tdi bumper mounted rear lights

How to wire spotlights

12/24v stuff split charging etc

Useful wiring info

Carling switch wiring

Battery cut off

Low Coolant Alarm

Madman EGT Gauge

VDO gauge info

A127 magnetti marinelli Alternator reconditioning

wiring colours Land Rover

A127 alternator regulator replacement

Nanocom Diagnostics/Fault Codes

Defender rear wiper motor refurb

Definitive-rear-wiper-wiring-for-amr3676 or LR078424 in to a earlier 90 or 110.

Alarm spider/non starting/intermittent starting issues

Discovery 1 electric seat switch repair

Twin alternator set up

Twin Fan install

200TDI glow plug connections

200Tdi retro-fit info Disco ∨ R/Rover Classic 200Tdi into a Defender

Split charging

Heated rear window relay

Defender fan speed from 2 to 3 modification

Adding intermittent wash/wipe to an older 90-110

Variable Intermittent Wiper Modification

Defender intermittent wipers

Split charging 2

Dual alternators

Intermittent rear wash wipe on a defender

Intermittent rear wiper installation for Defender

Park brake warning light

V8 ECU problems

V8 HT Lead layout

Rover 4.6 P38 Engine Wiring Diagram, About to squirt a p38 lump

Electronic Ignition

300TDI alarm keyfob battery changing

Defender wiper switch internals and spring position

Alternator upgrades

Headlamp upgrades

300TDI wiring diagrams

How to replace wiper motor park switch

Hazard Switch & Indicators - fault diagnosis,

Defender heated front screen

The Definitive Alarm Spider Post

Defender/Disco/Freelander front wing side indicator repeater lamps

Extra front light switch & wiring for Td5 Defenders

Upgrading headlight wiring

TD5 fuel pump electric plug?

Td5 Gauges – Bulb Information

Td5 Speedo Mileage run up circuit

fitting Td5 dash into earlier models thread [wibbly wobbly speedo]

TD5 Dash install

new light for Td5 hazard warning switch

2nd alternator on a TD5

TD5 dash into earlier models connectors etc

TD5 Stater Solenoid Contacts

1999 model year Td5 wiring diagrams

TD5/PUMA central locking distance fix

Engines Diesel/Petrol/Gas

Replacing the starter ring at home

Changing 300 TDi valve stem seals with head on

300Tdi ROW fuel line fittings

Fitting a 300Tdi into a older pre Tdi 90 or 110

Replacing the Front CrankShaft Oil Seal - TIP

Bosch Injection Pump repair by Simonb

Oil pressure switches/specs

2.5 N/A head gasket replacement

Injection pump information

300TDi vin range/info re cambelt kits

300TDI water pump replacement

300TDI tappets adjusting/checking/setting

Auto oil cooler relocation

Tuning the 2.25

Megasquirt2

Megasquirt 3

Megasquirt tech

Megasquirt full install

Megajolt installation

Tdi Injection Pump Breather Leak

TDi injector spill return pipe issues

200TDI cambelt change

300TDI cambelt and kit 2

300TDI aux drive belt tensioner bearing change

sealing the 200-300TDI Airbox

Fitting a 200TDI Disco engine into a defender

Adding an intercooler to a S111

Fitting an EGT Gauge

EGT response times

200/300TDI tuning

VNT turbo info

Catalyst removal on 300TDI Disco/Defender

Td5 engine surging/turbo overboost

Waterproofing a V8

V8 Basics leads/cap/rotor etc

Stripping a Turbo

Cambelt failure reasons/suggestions

Injection pump seal replacement in situ

Injector removal

Dealing with a snapped spark plug

300TDI thermostat replacement

200-300 TDI head gasket Info

Series lift pump replacement

Adjusting tappets

Intermediate gasket

300TDI cylinder head removal

2.5 N/A timing belt replacement

Freelander 1.8 timing belt change

The proper way to build a V8 by Ian Bull Car Cowboy

Rover V8 - Head Bolts AND Inlet Manifold Bolts - order

200Tdi oil dipstick loose & LR Tech Bulletin on how to fix it

Fitting a 200Tdi hand throttle

300Tdi Vacuum Pump Oil Leak repair

Piston Failue.pdf

Gearbox/Transfer box/Overdrive/Underdrives

Roamer drive noise problem on a Defender

Speedo driver gear list

 TD5 auto XYZ switch stripdown

 LT85 20c solid case rebuilt

R380 Discovery box to Defender box- shifting mechanism

Freelander drivetrain

R380 rebuild

LT77 Rebuild

Slave Cylinder replacement

Slave cylinder push rod

Defender clutch change

TD5 and Late TDi master cylinder change

Identifying gearboxes

LT230 rebuild

LT230 leak fix without strip down

A-Z of gearing

Tip for fitting a Transfer Box

Options for reducing gearing ratios

Crawler box install

 GKN Overdrive - thoughts on

GKN overdrive fitting to a Defender

 GKN Overdrive Strip Down

Output shaft oil seal repair

LT230 front output bearing replacement

Adapting an LT77 to fit a V8

Testing a Viscous Coupling

Transfer Box Ratios

Discovery clutch change

Auto gearbox kickdown cable adjusting caution!

LT230 rear bearing and seal replacement

Bell housings

LT230 2wd conversion

X-Eng handbrake fitting to a defender

X-brake servicing

Freelander drivetrain set up

Manuals

Land Rover Manuals NZ website

MOD 90/110 TUM[HS] Manuals

101 winch PTO repair and overhaul manual

 manuals

Link for more manuals

GKN Overdrive owners handbook & fitting instructions

Delphi Lucas CAV DPS information

Microcat

Zeus tables

MOT Testers Manual

Individual vehicle approval [IVA] information.

IVA requirements

 V8 Flapper diagnostics

V8 hotwire EFI

Defender Water Ingress Manual

Misc

Webasto Thermotop C problems & a solution.

Fuel Injector Information

Defender Triple Wiper Upgrade

windscreen crank gear on a Defender

How to replace the lock barrel on a Defender fuel cap – pre TD5.

TD5 Fuel Cap Key

Veg Oil Install on A Defender TDI

Megajolt install

K&N Filters

Aluminium specs

Bandsaw blades specs/selection

Removing snapped halfshafts insitu

Defender Safari Snorkel template

Defender central locking install

Defender wiper upgrade

Eberspacher install in a 110

Defender heater checks

300TDI vacum pump repair

Faulty goods/bad workmanship/warranty issues

Mig welders/tips/advice etc

How can I assess the weldability of materials

Rivnut fixing -- [Video]

Sharpening drill bits

RR seat reset

Defender buying guide

Tool Sizes for specific jobs

Fixing/Servicing a Tubela tube bender

EPC with Windows XP

EPC Removal

EPC using Windows Vista

Good ideas

Conversion tables

Onboard air threads links

PDAs/GPS etc

PDA port splitter

Tyre valve protection

V8 Auto conversion

Intermittent rear wash wipe on a Defender

Welding Equipment

Setting up Radios and SWR on CB etc

Fitting a CB to a Defender

DVLA points system

Knots and all you needed to know about them

Spark plug info

Oil and filter change

Fuel filter change

TD5 fuel pump checking/replacement insitu

TD5 Defender 110 Auxiliary fuel tank

Fitting Helicoils

Discovery Dim clock display?

Drop arm ball joint

Stazwork double bead locks

Tubed/Tubless wheels and the difference

Cutom V8 exhaust

Viscous Fan operation

Disco 300TDI replacement for a 2.5TD into a Defender

Fitting Webasto Thermotop DW50 into a 90/110.

How to convert TDI to Veg oil

Propshafts

Prop shaft lengths

Disco2 prop on a defender(vibration) problems solved

Bespoke Propshaft for a 90

Propshafts and UJs

UJ replacement

Protection

Rollcage specs/Blue book

ALRC roll cage regs

Roll cages

Roll cage tube info

Welding a cage in a Defender

Defender storage lockers

Waxoyling

Front Diff guards

Strengthened cross member

110 station wagon internal roll cage install

Defender wing bars

Northoffroad wing bars

Recovery ideas/Equip

Recovery info

Recovery points

Tow straps

Strops etc

Recovery points

Mounting a high lift jack

Suspension/Steering

Mini Tech - How to set your tracking on your own !

rubber boots for steering ball joints on track & drag link rods

Overhaul of a 200 TDI Power Steering Pump

Hockey stick/Radius arm bush fitting

PAS box rebuild and mods

RR Eas valve replacement

Defender Suspension upgrades/Lift etc

Radius arm bush changing

Hockey stick/Radius arm bush fitting

Castor correction

Spring info

Dislocation/Relocation

300TDI PAS pump replacement

Shock absorber lengths

LR Suspension - Springs For All

Changing air suspension bladders

Steering wheels-what fits what

Steering gone stiff/tight spots lock to lock?

Replacing a V8 power steering pump in a 110

90 suspension upgrade

http://www.aulro.com/afvb/90-110-130-defender-county/163070-td5-defender-alarm-query.html

10AS Grey plug connections



And here is the Green Plug connections

Sorry if this has already been covered, I did a couple of searches but they seemed very slow and unproductive this morning...

I got the headline message a few months ago now, so I put the Gap IID tool on it and found no faults on the camera.

Next did a few searches (here and other places) and google pulled up loads of horror stories... "£600 for main dealer to investigate - still not fixed", "replace camera loom", "replace camera" etc etc.

But my camera sometimes worked for just a few seconds so I didn't think it was actually a problem with the camera..

Then I remembered that there was  as fault code on one of the rear parking sensors, so I changed that (cost £11 ish, I think) and that fixed it.

I would strongly advise washing the car thoroughly before starting this job (the bumper traps a lot of mud), and arm yourself with some anti-rust products before removing the bumper 😉😆. Youtube shows where all the gotchas are (hiddent trim pins for example), but for me the most difficult aspect of the job was separating the parking sensor loom connector while balancing an ungainly bumper on my knees...

Further googling would appear to indicate the the camera is 'dumb' and can't throw any codes, but that if any of the sensors a faulty then the whole of the system is deemed faulty and stops working. So in my case a single faulty rear sensor stopped all other sensors, and the camera from working. I earn my beer tokens as a programmer, and boy, is this lazy exception handling!

Oh and one more thing - it appears that the reversing lights may be included in the "reversing system" since even after replacing the faulty sensor, the camera didn't work until I plugged the rear light units back in...

Hope this helps somebody.

Rog

this is to prevent the archives being inadvertently deleted or corrupted.

all existing posts in these subject archives have been locked, 

last year it took me almost a week to rectify  lots of corrupted links & I do not want to go through that again.

Originally out of a Disco 200TDi , these are chunky things - the end 'tanks' being 5mm thick cast alloy.

First thing I thought to myself was "bugger! that ain't going to fit". Judging by other vehicles' intercooler positions - they are always placed in a forced air location, so putting it under the passenger seat wasn't really an option.

The inlet and outlet pipes are pointing in the wrong direction for me - I needed them to both exit at the same end so they can then be fed through the side of the front panel and hopefully in an easy fashion to the turbo and snorkel.

A few things I had to consider:-

(1) Ease of fitting

(2) Ease of connecting to the rest of the vehicle

(3) Not having to move other things to fit it.

(4) Little if any 'adjustment' to the bodywork (catflap is a series vehicle, and I want him to keep his identity)

(5) The use of readily available parts to finish the job

Lots of pics again, courtesy of the gallery. First two are what a 200TDi intercooler looks like:-

The inlet and outlet pipes more than double the width of it.

They also point in the wrong direction

Cutting and grinding alloy is a bit of a pain, regular squirts with WD40 helps to prevent clogging of grinding/cutting blades.

The pipes have been removed and ground back to be flush with the rest of the alloy.

Considerably thinner now.

Cut two same size holes in the side (54mm)

The old holes have to be blanked off. I used 3mm plate, blind rivets, and P40 filler to seal it against leaks.

The corner one has only three rivets. This is because there isn't much alloy to drill and I didn't want to make a mess. The filler completes the seal and the thickness of the plate makes the job ok I think.

The pipe on the left is the original one I cut off. I don't have any pipe the same diameter, so I had to alter the bigger pipe on the right to the same size. I also thought it wise to use long pieces so that they can be cut to fit at a later date. As the original pipe is the same diameter as the turbo to manifold connection - I could use a couple of the 90dg bends that connect the turbo to the inlet manifold to turn the pipes from the intercooler to almost directly at the engine.

Slit the pipe and (guessed) remove 15mm strip.

The pipe is then clamped closed, seam welded, and then the weld ground down smooth.

The pipes have to be secured to the intercooler body by bolts, so I made a suitable flange and welded the pipe to it - again seam welded to prevent air leaks.

4 M5 x 0.8 bolts hold each pipe in place.

The finished article. Looks a bit odd, but it's what I was looking to achieve.

From the top - 95mm wide now, the available space between the radiator frame and the inner edge of the front panel is 130mm, plus the pipes should exit nice and neat by the end of the radiator.

Best give it a splash of paint now - the bare steel will rust fairly quick.

Not much more to add really. I'll use the original method of mounting it - the bottom to the front crossmember, and the top to the front panel via a DIY bracket. This type of job wasn't so much difficult as needing a lot of thought. It took me two days to do, but it can be done in a day if you get on with it.

Les.

I had a couple of jobs to do on a 300TDi Disco today, so I thought a couple of Tech threads might be in order.

This is the fan belt tensioner bearing replacement.

Not a very difficult job to do really, a bit fiddly, and you need to have a vice or similar means of gripping.

Wear of the bearing is identified by a hissing noise coming from the tensioner whilst the engine is running. Removal of the belt will allow you to spin the tensioner wheel and any wear will be obvious. A small amount of movement forwards and backwards is ok, but a dry rushing noise, uneven feel, or other play, means the bearing has to be replaced. While engine damage will not happen if the bearing fails - the worn wheel will throw the belt off in the end, and you'll be stuck at the side of the road.

Normally you would need to buy the whole wheel, and it's £43 from Bearmach, and god knows how much from the main dealer. As in a lot of things, there's a trick to removing the bearing, which is a lot cheaper.

This is the tensioner in place and doing it's job.

The bolt that holds the wheel on the tensioner body is opposite thread, so 15mm socket and lever in an anti-clockwise direction to release tension from the belt and lift it off the wheel. The tensioner will move anti-clockwise until it comes to it's own stop.

Now click the rachet in the opposite direction and undo the centre bolt (clockwise) The wheel will then lift off easily. This is the removed wheel with centre bearing clearly shown.

Now the bit that isn't recommended, but I don't see why there's a problem doing this.

The bearing is a pressed fit in the centre of the wheel and then retained by a snap ring. These things are almost impossible to remove - hence the need to buy the whole wheel.

I file a notch as shown, far enough down to be able to apply side pressure to the snap ring, which then is easily removed.

The old bearing is easily pressed out using a suitable drift. The wheel is made out of cast iron, so take care not to fracture it. I used an old socket and a nylon mallet to knock it out.

I took the old bearing to Thamesdown Bearings where they matched it up. The new bearing is made by SKF, and as a reference, the part number is 6203-2RSH.

Don't bash the new bearing in, it's very small and can be easily damaged. I used a 30mm socket (same diameter as the bearing), and pressed it in.

Replace the snap ring, and the wheel is ready to be put back on. Use a small amount of thread lock on the bolt.

Quite an easy and cheap job to do.

Edited to add information from forum member Rejo.:-

This same bearing will replace the one in the air con belt tensioner.

Les.

some time back I fitted a front wash/wipe intermittent system to my '89 110, all the info is below, in edited form

Done this using the geniune parts, you need harness PRC8295 and relay AMR2341, remove the fuse box cover, pull the mat away from the sides of the fuse box, take out one screw each side,disconnect the wiper connector, plug in the new harness, plug the new relay into the new section of harness, refit all the removed screws and covers, switch on and play with the wipers to check it all works, should now have intermittent wipe when switch is down, slow and fast speeds when switch is up, push wash and should get wash with 4 wipes. the parts are quite reasonably priced as well, as I say done this on my '89 110 all works fine, a good mod for all 90\110 which don't have intermittent wash\wipe.

on checking the cable routing on my 110, with the relay and it's socket behind the fuse box, the 2 legs of the harness go up the tunnel, where all the other cables go, (may need a 'fishing rod' or string to pull them up through here) to the back of the radio\rear wiper switch, from here they travel along to the front wiper stalk inside the steering column cover,remove this cover for access, inside here disconnect the front wiper stalk connectors, reconnect these 2 to the new harness, make sure everything is safe, switch on the ignition and test the new system, if all OK, refit the previously removed covers\ fusebox. it's not quite as simple as it appears in my original paragraph above.

on the new harness at the wiper switch end connector there are 6 wires which matches the switch connector wires and colours. A quick look at wiring diagram in my workshop manual shows connector with 5 wires going to wiper motor, connector with 6 wires going to wash\wipe switch on steering column

Checked parts cat. If you have this wash\wipe switch fitted PRC3900 upto VIN FA455595, reckon you need this later one PRC7370 switch wash\wipe delay from VIN FA455596, the early one is most likely to be unavailable, probably superseeded by the later number.

Additional info ------------ also relay PRC6864 from early Discovery & Range Rover will work, it was superseded by AMR2341.

if anyone wants to make a homemade harness, you''ll need to know the relay pin idents

manuals

But In my experience, there is more to it. Mainly maintenance; how often do you grease your U/Js? And the next question is than how is it done. Before you all think I teaching you to suck eggs I will expand on this  a bit more: Problem I found is that one grease nipple is serving 4 bearings. In reality, this means that the grease tend to find the route with the least resistance. This usually means you are effectively greasing 1 or 2 bearings only. And what about the others? They are dry as a bone and fall apart. 

To combat this, I thought about it, and came up with a method that I will show you here. It is rather involved, but I have not changed a U/J in 10 years. Here we go:

First off, grease as you would normally. You can see which bearing gets grease, as it pours past the seal:

The ones that dont get any grease need feeding as well. You can do this by pressing the bearing which has already been greased against the crosspiece like so:

This now should stop the flow of grease to the already greased bearing, and find the next passage with the lowest resistance.

If you still have other bearings that have no grease coming out, you can add a G-clamp with a nut, to press 2 opposed bearing cups against the cross piece. keep repeating this process until all bearing cups have grease coming out.

This process is rather fiddly, but as mentioned, since I started doing it this way, I have had no failures. I have done this with the props on the car and using 2 opposed G-clamps. Also, the blue grease is better in my experience, as it does not go solid like the yellow stuff (which I am using here, unfortunately).

Hope that helps, and have fun greasing these things!

Daan 

A helpful list of fuel injector part numbers, operating pressures, flow rates etc.

http://forums.lr4x4.com/index.php?showtopic=96857

I've had intermittant faults with the ABS system for about the last three years, but up until recently, it has always been one of the wheel hub's going bad. Over the last few months the warning lights on the dash have been coming on and going out totaly at random. I thought another wheel bearing was starting to go again but this time they were all O.K.

These last few weeks the warning lights have been on constantly so I had a friend in the motor trade read the codes and, just as I suspected, the fault did not lie in the axels but in the ABS unit under the bonnet. The two faults listed were Shuttle Valve Switch - Long Term Failure and Shuttle Valve - Electrical Failure.

After a search I found http://www.landroverclubvi.com/abs-mod.html . I was a little unsure at first as to whether such a simple (Option 2) fix would solve the problem but, with nothing to loose, I gave it a go yesterday. Two hours later I turned on the ignition key, and after the initial check, all the lights on the dash went out! Took the car for a test drive and everything is working as it should do - ABS and traction control are back, I havn't been able to test the HDC (it never gets used) but it should be fine. All for the cost of my time and about £1's worth of wire and connectors. (A new ABS unit is approx. £1400)

This won't mean a lot to those who have never had to stare at those dam lights on the dash and listen to the bong, bong, bong of the warning buzzer all the time but it might just help somebody here in the future.

Peter.

 Safari snorkel template [300tdi onwards]

Axles/Diffs/Driveshafts
 

Axle refurbishment


Brakes
 

X-Brake servicing/overhaul
X-Brake fitting to 110

RR or Discovery 1 handbrake lever fit to a 90 or 110 Defender [1983 to 2016 only] 

Clutch & Gearbox
 

Fitting a 300tdi Clutch pedal spring


Electrical & Instruments
 

Substitute driving light switch for TD5 center console
Td5 instrument pack fitting to older 90/110 models
Intermittent front wiper relay change & mod for older vehicles
Headlight wiring upgrade 1
Headlight wiring upgrade 2
step by step to wiring spotlights
roof mounted front lightbar wiring
low coolant level alarm 1
low coolant level alarm 2
Replacing cigarette lighter with USB socket (wiring)
Defender Triple Wiper Upgrade
front screen washer upgrade 1
front screen washer upgrade 2
Heated Washer Jets
clear lens headlights 1
clear lens headlight 2
LED sidelights and indicators
How to fit a Dual Din to a TD5 dash console

Ignition Systems
 

MS-Megasquirt/Jolt


Reversing camera & dash camera
 

Reversing camera kit 

Reversing CCTV
In Cab Video Recorder

Suspension & Steering
 

Discovery drop arm on Defender
Fitting PAS to a SeriesLR using standard LR parts

http://forums.lr4x4.com/index.php?showtopic=91019

http://forums.lr4x4.com/index.php?showtopic=89688

one hi-lift each side with the lift pad facing inwards just to the rear of bulkhead bottom mount, 45 gallon barrel placed each side with a beam ready to slide in, we removed the front grille panel so no need to lift it over the engine, rear end was left sat on chassis [all body mount bolts removed] front end raised enough to get the beam & barrels in place but just clear so wheels/tyres could pass without touching, rear end of body lifted just enough to clear chassis,

rear beam & barrels placed in to support under the 2nd row rear seat cross member & chassis rolled out, & parked out of the way, body was then lifted enough to move the barrels further in under the body to give more support, front end done first then rear, as in the body photo's above.

the forward beam sits under bulkhead & rear beam sits under the rear seats cross member, all nicely supported, just waiting for the new chassis to be rolled under & body refitted.

A common failure on Discovery Series 1 vehicles (both Tdi & V8) with the two-button alarm system (i.e. all vehicles from 1996 model year to 1998 model year) is a component called the "spider".

Symptoms of this failure are typically an intermittent non-start or cutting out while driving (or both), which usually gets progressively worse until it is happening very regularly. Typically you will find that leaving the vehicle from a few minutes to a few hours will allow it to be started, only for the fault to repeat later on.

The spider unit is a small black box of relays, controlled by the immobiliser & alarm, mounted on a panel just in front of (toward the front of the vehicle) and below the radiocassette slot - a very inconvenient position which is designed to be very inaccessible to thieves in a hurry. This contains relays which isolate various key circuits of the vehicle; the feed to the fuel solenoid, and the feed to the starter solenoid on a 300Tdi, and ignition, fuel and starting circuits on a V8. A combination of heat, vibration and a not very good quality circuit board eventually results in a dry solder joint on the circuit tracks inside this unit, which often then get hot and burn out completely. It happened to my 1996MY Discovery V8i, the first one I ever saw with the problem in about 1998/99, and it took me about three months to find the fault by which time I was not in a very good mood ... the purpose of this post is to prevent anybody else having to relive the level of irritation I faced with a vehicle which would sometimes start, sometimes not, sometimes cut out while driving and then come back to life while coasting to a stop, sometimes die at junctions, sometimes die for an hour or more at a time.

So far, I have seen the fault affect both the fuel and cranking circuits on different 300Tdi vehicles, and the ignition circuits on my V8. I assume it can also affect the other circuits on the V8.

Diagnosis

Before you do anything else check all the fuses and that the battery is OK - it's really very annoying to pull everything to bits only to find a blown fuse somewhere! The next thing to do is to check that the immobiliser is not actually active - if it is, there will be a red "key" symbol in the dash when you try to start the engine - and if there is then the problem is elsewhere, perhaps the alarm ECU, key fob programming or whatever.

First you need to identify and check the offending circuit. Does the vehicle crank and not fire, or does it not crank over?

If it cranks but does not fire, then the problem is in the fuel solenoid circuit on a Tdi, or ignition/fuel on a V8.

Take a digital voltmeter (DVM) and check if the fuel solenoid (Tdi) or ignition coil/fuel pump (V8) has a 12 volt supply to it by connecting the meter to the relevant blade connector and earth and turning the key to position 1 (on). If there is a 12 volt supply to the circuit, then the fault probably lies elsewhere. (Note that a dry joint may not always provide a perfect break in the circuit; on my own vehicle, it caused a voltage drop at the coil which was only apparent once you started cranking. As a result all appeared OK at rest, but when you tried to crank there was no spark. As I "knew" there was power to the coil, I didn't look at this any further, so it took rather a long time to find out that the power consumption when cranking was causing a voltage drop at the coil, which in turn caused the ignition amplifier module to cut out).

The connectors you are looking for are:

- The small blade connector on the back of a 300Tdi fuel pump, down by where the injector pipes come out

- The + connector on the coil of a V8

...if it's the V8 fuel pump you're on your own as I haven't had that out!

If there is no voltage at the circuit in question, then the next stage is to take the spider unit out - jump down to Repair.

If it does not crank, then the problem is in the starter circuit (Tdi or V8, much the same on both). Take the thin lead off the starter solenoid on top of the starter motor, and stick a DVM between it and a good earth. Turn the key to position II (start). You should get 12 volts across the meter. If you do, then the fault is most likely with the starter motor ... but to be sure, put the lead back on, stick the meter probe into the back of the connector, and operate the starter again. If the voltage is still present but the starter isn't doing anything, it will be the starter. If the voltage does not appear under load, it will probably be the spider unit. Time to take the dash out...

Repair

Removing the spider unit

This is fun. Really fun in only the way that a dashboard with lots of fiddly little screws and bits that you can drop in inaccessible locations can be... allow 2-3 hours at least. You don't need many tools, in fact I think only a couple of Philips screwdrivers, a soldering iron/solder, and something to make some clock keys out of, plus the radio removal keys for your particular type of radio.

I suggest you get hold of a workshop manual for this as it makes life easier if you know what order to take things out in and where all the screws are hidden but a brief rundown is below -- sorry if I have forgotten anything but it's a while since I took one out.

- Disconnect the vehicle battery

- Remove the radio (you will need radio keys for this) and its cage

- Remove the ashtray & the blank switch panel on the opposite side (they just pull out)

- Remove the clock on one side and coin tray on the other (easiest way is to get 2 flat bits of metal about credit card thickness, slide in above and below the clock to release the retaining tabs and it just slides out)

- Remove the twin pop out cupholders (about six screws)

- Pull off the 3 rotary heating/ventilation controls

- Unscrew and remove the plastic surround to these

- Unscrew the heater controls so you can move the unit around

You will now be pretty much at the stage of being able to take the black centre console panel out ... so take the screws out and wriggle it out. It tends to catch on things but will pop out with a bit of a tug. The face vents etc come out with the console.

Behind all this you will find a small black box screwed to a metal face which slopes towards you at about 45 degrees. It has two screws holding it in and a 10 pin multiplug coming out the RH side which is covered up by a metal security plate so you can't easily disconnect it. Take the unit out. This is a "sealed for life unit" which it is not possible to repair. Ignore that sentence.

You will see that on the end of the box where the connector is, the plate is a press-in fit. Get a small flatblade screwdriver and lever out the end plate, working your way round until it pops out. The whole circuit board will slide out.

Look on the back of the circuit board (the solder side). Chances are the fault will be immediately obvious, if it is a little blackened and burned, but if not, examine all the solder joints carefully, if the unit has failed in the normal way there will be a "dry joint" (where the solder joint has cracked up making a bad connection) on one of the larger pins on the board. Basically all you need to do is to get a decent fairly high powered soldering iron with a small point on it (I use a 40 watt) and re-solder the broken connections. Depending on how much you enjoyed taking the unit out, you might also want to do all the other relay and connector pins while you are in there - it makes sense.

As an option of course you can replace the unit, I think it costs about £40 or so and the part number is on the unit, usually AMR4889.

Put the box back together once it has cooled off a bit, and connect it up. At this point it makes sense to test the system before you put everything back in ... so reconnect the battery and fire it up - hopefully everything will now work!

Assuming it does the remaining steps are simple:

- disconnect the battery again,

- throw all the dash back in,

- congratulate yourself on fixing a unit that isn't supposed to be fixed

- reconnect battery, set clock & radio code etc etc

- Robert is your mother's brother go for a beer

One for the technical archive I hope, once somebody points out something I am bound to have forgotten somewhere

I cannot begin to explain the aggravation this caused me and the amount of work that went into finding one teeny little dry joint on a circuit board inside a sealed unit for which there is no circuit diagram hidden right in the guts of the dashboard ... so I thought it was worth sharing the detail in order that others don't have to go through the "learning process" I did!

There is indeed a bypass solution (on the fuel (Diesel only) solenoid side of things anyway).

Just supply it with a ignition conrolled 12V supply. Not always considered a 'proper' fix but it worked form me no probs.

Oh and if this circuit completelty lets you down (and it will!!!) leaving you no way of getting home simply take the solenoid controlled plunger (again Diesel only) out of the stop valve and put it back together.

Your car will now start BUT it will not stop running when you turn the ignition off so you have to stall it when you get home and then either fix it as per Stephen's post ie the 'proper way' or as above 'The cheapskate way'

OK a few other bits...

The spider circuitry is detailed in the official 1996 Discovery Electrical Troubleshooting Manual, though I always found the circuit diagrams in that as clear as mud! The official name for this horrible little box of nightmares is "Engine Immobilisation Control Unit (Spider) (Z271)" and it appears on various pages to do with starting and charging though AFAIK there is no single diagram anywhere in any of the literature that shows the whole thing and there is certainly nothing showing what goes on inside it - I suppose that is a security measure.

You can do a bypass of any of the circuits as a temporary measure, though the V8 fuel pump would be rather hard I think as you'd have to pull the floor up in the back - probably easier to fix it properly! However, since you need to take the thing out to be sure that this is the problem, once you have it out you might as well fix it anyway.

The final straw for me on this one actually happened after I fixed it. I'd been working on it from 9am one Saturday morning, checking and following through all the circuits in turn, I was at the spider unit when I found almost by accident there was an odd 3 volt drop across the input and output wires. As the fault only occurred when cranking I'd not spotted the difference between the voltage drop caused by the starter, and the extra voltage drop over the dry joint. I pulled the thing to bits and was unbelievably chuffed when I found it was all burnt up inside because I knew I'd found the problem. Finally, at about 4pm that afternoon, I had it all back in to the vehicle, fired it up and away it went, a dozen or more stop/starts later and I knew it was good to go.

Opened the garage door...

...selected reverse (she was still a manual at that point) ...

... and the %%%%ing grub screw came out of the gear selection linkage!!!

Nearly a year later... I finally have some pictures to add to this so it makes a bit more sense!

Thanks to Underdog for most of the pictures, a couple of the circuit board ones are mine as I just fixed another spider for somebody yesterday, but most are Ian's.

Take out the heater controls...

...take out the clock & hazard light switches, and the switch blanks from underneath...

...take out the coin tray and ashtray (note one of the screws in behind the coin tray, this holds the whole centre console panel in)...

...out with the radio etc, and then the drinks holder from underneath...

...then once you have found all the screws, pull out the whole main plastic centre console panel so it looks like this...

Now you can see the spider (arrowed)

Unscrew the two screws holding it in, pull it out, then unplug it...

...and here it is, the little *&*&%$^ Resist the temptation to stamp on it, as you can't buy them any more!

Carefully lever out the end plate with a flat bladed screwdriver and the circuit board will slide out...

See the problem?

If not, look a little closer at the arrowed joints, particularly the top left one....

A less than perfect bit of soldering While you are in there, re-solder all the pins going onto the multiplug in the end, and all the pins going onto the 2 relays on the board, as any of them can go and I don't suppose you want to take it out again! The re-soldered article ready to go back together:

It can be much worse and more obvious than this, in extreme cases the tracks can be burnt away and you have to re-build the tracks joining the pins, which I do with fine solid-core wire, but even one that is only just starting to go is not hard to spot when you know where to look. Which is why it took me 3 months to find mine when it originally happened.... because I didn't

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