Air Springs and Hoses

The mornings after we took the Discovery off road we awoke to find it sitting on its haunches.

We have been to off-road courses twice in the last month and it has happened both times.  Its not a big problem because in both cases starting the car pumped up the suspension and it drove properly. After that the springs remained inflated and behaved as expected.

I did a bit of reading and apparently the air spring should be replaced every 5 years.  I've had the car over 5 years so I know they have not been done.  Swapping the springs for new ones sounded relatively straight forward.  There are several other sites with guides plus the workshop manual is clear.

http://www.discovery2.co.uk/Rear%20Air%20Springs.html

http://www.landyzone.co.uk/lz/f38/disco-ii-air-suspension-definitive-guide-61211.html

I ordered the air springs (RKB101200) and the clips to go with them plus a few spare clips (NTC9449) just in case I dropped any.  

The genuine Land Rover air springs are very expensive but there are OEM versions for considerably less.  My original Land Rover air springs have the manufacturer stamp of Contitech in addition to the Land Rover stamp and part number.  The Britpart OEM versions are made by the same people.  According to various forums the Dunlop springs were never fitted to Discoveries but have been used on other models and are frequently used on lorries.

Having the parts I thought I needed I started the job.  After jacking it up and getting the axle stands under it I spotted two snags!

Snag One

The air hose on just the drivers side of my car was already very taut and all the instructions and some advice on the phone from Torque Performance, who I had phoned on an unrelated matter, confirmed that the only way to remove the old spring was to cut the hose. 

The cut should be close to the brass collet and this would not normally be a problem but on mine the remaining hose would be too short to fit the new spring!

I tracked the hose back and removed some clips but getting any extra slack was going to be tricky.

Snag Two

You need to deflate the spring to be able to remove it!

The official method is to attach the TestBook computer and instruct the Self Leveling Anti-lock Braking System (SLABS) ECU to deflate the springs.

That was the final confirmation that I needed my own Nanocom which is now on order.

There were three other methods to deflate the springs.  Cut the hose, stab the spring and remove the connection from the compressor.  Two out of three of those are destructive and the other assumes that the collet removed would go back in and seal when refitting.

I did not want to take the chance of having the vehicle undriveable because I did not have any replacement hose or connectors.

I carefully put the vehicle back on the ground and checked it was all still functioning correctly.

What Next?

I could buy the Land Rover replacement air hose harness.  Not just one hose but you have to buy the whole lot!  That appeared to be unnecessarily expensive and a fiddly job under the car to fit.

After a bit of investigation I found that the hose can be repaired with  standard 4mm pneumatic hose and some straight push fit joiners.  I could use the same idea to extend it.

As this is a significant part of the suspension I was being safety conscious and not just trusting a single eBay advert.

Further investigation into the air spring setup indicated that the compressor can reach just over 10 bar.  I cannot confirm that by other sources but as I could only find two types of hose, polyurethane and Nylon, the choice was easy.

The polyurethane is only rated at 10 bar but the Nylon had ratings starting at over 26 bar and it had a more appropriate working temperature range typically from -35C to +70C.

http://www.kingindustrial.co.uk/pneufnm.htm

The easiest place I found that could supply the 4mm Outside Diameter with 2.5mm Inside Diameter Nylon tube was on eBay.  

I also found the Legris straight joiner from RS was probably the better choice for the joiner because theirs are rated at 20 bar where the more common make available on eBay and other places appear to be only rated at 10 bar.

But What Did I do?

I decided, after having done all that research, to let the garage do it.

With it up on their ramp they were able to find enough slack in the existing tube and they replaced the air springs.

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Appendix

Tube cutter: http://uk.rs-online.com/web/p/tube-cutters/0722198/

Suspension bits:

http://www.famousfour.co.uk/search?string=air+spring+hose&veh=disco_2&sec=spst

http://www.johncraddockltd.co.uk/land-rover-discovery/discovery-2/parts/suspension/

Matching Rear Bumper Fitting

Shelley has wanted me to get a rear bumper that matches the front heavy duty bumper ever since I fitted the front one.

The damage caused by our earlier off-road trip has forced the issue.  At the LRO Show in Peterborough the other weekend I finally selected one I liked.  After a lot of back and forth I selected the Torque Performance (TP4x4) one.  That is the same make as the front bumper I have.

One of the reasons I liked it was because it looked easy to fit. The other bumpers available used two of the towbar bolts but this one uses two spare holes near the existing bumper mounts.

The people on the stand did mention that it needed some body work cutting to finish the job but a bit more on that towards the end.

Removing the existing bumper is easy.  I won't repeat myself too much as the removal details are shown on my post about fitting a tow bar.

In summary:

• Remove the rear bumper lights
• Disconnect the light and reversing sensor cabling
• Undo two bolts

The old bumper should now be off.

I then tidied up the now redundant reversing sensor connector with a bit of tape and cable ties.

With the TP4x4 bumper the plastic sill cover is not used.  The new bumper overlaps the chassis and does not need and will not fit with the cover in place.

This is held in with trim clips which need to have the centres pushed through and the clips pulled out of the body.

With that out of the way the bumper can be bolted in.  But STOP!

If you want to fit towbar electrics to the inset mounting on the bumper do that BEFORE fitting the bumper.  Once the bumper is on the car you cannot get behind to get the towbar socket bolted in!  Guess how I found that out!

Back to fitting the bumper.

There are two spacers one either side.  The bolt passes through the bumper, through one of the bolt holes in a spacer and in to the original threaded bumper mounting hole.  I spray painted the bolt heads black to match the bumper before fitting.

Attach both of the bolts in to the threaded holes first but do not tighten.  You need a little bit of free play to get the other bolts through their holes.  Fix those with the washer and nut.

Tighten them all up.  I assumed a torque setting of 45Nm as per the original bumper bolts.  This very slightly indented the metal so perhaps a little less torque might be better.

[Update: see my newer post in September 2016 where I make my own spacers that I think work better.]

Connect up the lights and clip them back in and the bumper is on and ready to go.

As you can see from the photo, the line of the bodywork does not meet up with the bumper.  My intention was to do as the person from Torque Performance had suggested and trim the body work back to the wheel arch in line with the bumper.

So far I have not done that.  The step looks fine and the only thing I think it needs is some form of plastic end cap to finish off the trim.  If you don't have a towbar then trimming the rear panel will give you a better departure angle but it will make little difference for me.  I may still trim it but at the moment I am happy with the result.

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Update September 2016: The powder coat had fallen off and the bumpers rusting so I have cleaned them up and coated in U-POL Raptor load bed liner.

Self Fixing Reversing Lights

My reversing lights have not been working for weeks.  After having done the normal stuff the garage assumed that the fault is something to do with the reconditioned gear box and it is booked in on Monday to have an investigation under the gear box warranty.

I know the reversing lights were not working on Friday evening because I remember thinking its getting dark and it would be easier with reversing lights.

Today, Saturday, they have started working.  I first noticed them when my wife was manoeuvring to hook up the harrow in the field, first thing this morning.  Since then the reversing lights have worked every time!

They must know they are booked in to the garage on Monday!  :-)

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Update Sunday:

The reversing lights are still working.

The only thing I did to the Discovery between Friday night and Saturday morning before I notice the lights were working, was to connect my new Nanocom.  I did not make any changes, I just had a nose round to see what the Nanocom could read and make sure it was working.

I have checked the circuit diagram and the reversing lights do not rely on the Body Control Unit (BCU) or any other Electronic Control Unit (ECU) in the car.  There is a feed to the BCU but the switch in the gearbox is what should turn on and off the lights.

I'm still puzzled!

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Update Tuesday:

The reversing lights stopped working again yesterday after I had told the garage there was nothing to fix.  The mysterious self correction was only temporary for the weekend.

Before taking it back to the garage this morning I wanted to check the cables for myself.  I made up and plugged in a simple test loop to short where the switch would normally be.  The lights worked therefore it must be a switch fault...

When I plugged back in the switch it now worked!

As I had not touched the switch just the connector it now pointed to a problem with the joint where the switch cable joined the main loom.   That was difficult to check on my own and Shelley was already at work, so I took it in to the garage as planned. With one person wiggling and another watching the lights the garage confirmed the fault and narrowed it down to the exact point.

With hindsight this should probably have been one of the first things to try but what with having already had a worn out switch a faulty new switch and now faulty cabling it was just too many things going wrong at the same time.

Fingers crossed it is fixed now.

Under Towbar Slider

Having a towbar can be an issue when used for competitive off-road events or pay and play days. The metalwork significantly reduces the departure angle and digs in to the ground. In the worst cases it stops you moving.

I have selected a towbar that has the minimum height and no unnecessary overhang but it still has the potential to act like a drag anchor.

To reduce this effect I came up with the idea of fitting under body protection under the towbar to also act as a smooth surface to drag along the ground rather than the towbar digging in.

The design is simple and based on the typical steering guards.  A big thick bit of alloy plate mounted on a steel frame.

I used a bit of stainless steel angle drilled to fit the tow ball mounting holes and two more bits to fit where the towbar side brackets fit on to the chassis. I added some extra holes in those as additional rescue tow points.

I hit a snag with the construction in that my own tools were not capable of making any holes, let alone large holes, in 6mm stainless steel!  Oops!

Luckily our Farrier is also a blacksmith and had a workshop full of tools capable of doing the job. Thanks to Dean the bits were made in no time at all.  He also had a giant guillotine to cut the 6mm alloy to shape.  I drilled the alloy and fitted the bits together on the car.

The alloy is fixed to the steel using stainless steel M8 round head bolts at the chassis end and counter sunk head bolts at the tow ball end to minimise the collection of mud.

The initial fitting was a bit rushed as we were going off-road that day and I finished drilling the vent holes another day.

I can see how effective the plate has been by the scratch marks, bend and burrs on the plate.

LRO Show Peterborough

What a day.

We headed for the off-road course first.  I joked that if we damaged anything we could then buy any spares we needed at the show.

The course was excellent fun as we expected for something Vince Cobley had organised.

We managed to slash a tyre.  One of the marshals flagged us down.  As it turned out we were not far from the end of the first trip round.

The tyre had a 5cm vertical gash and was completely flat.

The marshals were incredibly helpful.  They changed the wheel for the spare for us and found a working bottle jack because mine had a leak!  Back up and running for the next time round.

Many thanks to all the marshals who were excellent.

I thought the idea of getting a replacement tyre at the show was a good one but as it happened we did not see a tyre fitter there!

We did not spend much time looking at the arena events but spent most of the time doing the shops.

We treated the Disco to a new Torque Performance rear bumper.

Poor guys at the stand.  I visited 3 times before I made my mind up then had trouble getting enough cash together because the cash machine was out of order!  Got there in the end courtesy of some cash back at the sweet shop.

Came home with completely empty pockets.

A few jobs to do after the off-roading, including drying out one of the head lamps.

A fantastic day.


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Reminders:
MCB 4x4 for custom roof racks
Armson Automotive Engineers for chassis rust treatment

Off-Road Damage

I am not a stranger to damage from off-roading.  Although I like my car to look tidy most of the time that is not an excuse for us to ease off while off-road.

We bought our first and all subsequent Discoveries with the desire to drive them off road.

Yesterday we went to an off road pay and play site in Canewdon run by the Essex Rochford and District 4x4 club.

Their web pages are quite clear on the fact this is an extreme site and one of the first people who spoke to me when we arrived had kindly come over while I was signing in to point out that we would get the paint work scratched.

When we arrived it was nearly shiny, new looking wheels, new bumper and new steering guard.  Even the rope was new because I had bought one about the right length to neatly drape over the light bar.  I can imagine that people thought 'this guy has never been off road before.'

It was kind of them to caution me but only the car was new to this type of off-roading.

Sadly I have no photos of us while driving the course.  We were both in the car so have to stop to take photos.

We only went on the less extreme side of the site.  Even that is still aggressive.  Not for people who worry about damage.  Some of the trees are very close and the CB aerial spent most of the time horizontal until I gave up with it and took it off.

There was only one track we tried and could not get through.  Shelley managed to progress about 10 foot further than where we originally got stuck but eventually had to admit defeat and reverse out.  We nearly hit a 90 in our blind spot while reversing out and probably only just missed him due to his quick reactions.

He had come round to see if we needed a winch out.  I think he might have been disappointed that he didn't need the winch but we all had a good laugh at our luck for not colliding.

We had done well not to need a tow from anyone so decided not to push our luck.

Back at the start area we assessed the damage.  The front heavy duty bumper and steering guard were undamaged with just some drag marks on the steering guard.

The rear protection I had rushed to fit that morning under the tow bar had done it's job well.  The idea was to allow the back to slide instead of the tow bar digging in the ground.  Based on the scratch marks I am sure it worked.

Above the tow bar was another matter.  The rear bumper had been torn off one side and the offside reversing/fog light was missing.  Two of the reversing sensors had been pulled through the bumper.

I made the rear bumper safe for the journey home.  We jet washed some of the mud off but left all the splatter up the sides as evidence of our fun day.

The journey home felt like we had done some more damage.  My best guess was that we had jet washed off some wheel balance weights.  It vibrated a lot at some speeds and was smooth round most corners.

The good news is that I was able to clear out about a kilo of mud and stones from the front wheels using a screw driver.  A test drive proved that the mud had been the cause of the vibration.

I was able to straighten the bumper, once I'd removed a bent bracket that was in the way and secure it properly using screws instead of the plastic trim clips.

The quarter bumperette bits were also only held on by luck and although you can only see when offering up the plastic corner, the rear panel was slightly pushed in and needed to be pulled back out.

Shelley had told me when I fitted the front bumper that I should fit a matching heavy duty rear bumper but I thought I knew better!  I'm now looking for a new stronger rear bumper.

In-Car Fire Extinguisher

The Association of Land Rover clubs (ALRC) uses similar rules to the Motor Sports Association (MSA) in the UK regarding fire extinguishers.  The requirement is for quite a large size fire extinguisher for competitive events.  The sort of event I am likely to do with our Discovery is only going to be for Road Taxed vehicles and the fire extinguisher is only a recommendation according to the ALRC rules but better safe than sorry.

The requirements are for larger than a 1.75 litre capacity foam (AFFF) fire extinguisher. The nearest larger size I could find was 2 litre.

That is quite a big bottle to fit securely inside the car where it can be reached.  I was able to make a bracket to fit it, at a slight slant, under the rear of the drivers seat after having removed the ancient CD changer.  I used the bolts previously used for that CD changer to attach the bracket to.

The fire extinguisher is released by a catch and to avoid it snagging on the wire springs of the seat base, I fitted a plastic sheet simply held in place by cable ties.

This all works well and the fire extinguisher is out of sight most of the time.