Day 9: Electrics, carpets, temp sender

The start of lots of smaller jobs

So, as I mentioned yesterday, I am now at a stage where all of the big mechanical jobs are over. To the uninitiated, it now looks like I am close to completing the car, but the next phase of the build will take a while.

I still have carpeting, interior including seats, wings, boot, boot strakes, doors, rear lights and number plate light, weather equipment (tonneau, hood, wipers).

Its still going to take a while! But today is all mainly about carpets, testing and a little rework on the water temperature sensor.

Electrics (testing)

First thing this morning I connected the battery, found the key from its cool welcome box and turned the ignition on. This is quite a big moment. I haven’t got to the stage where I have fired up the engine yet, I am waiting for some specific competition running in oil and also need to rework the water temperature sender before I fill with coolant.

However, I tested all of the electrics and everything worked! All dash lights, headlights and front indicators working, horn, dash illumination, windscreen wiper motor, reversing light and fog are working.

And here is a shot of the mileage, which is rather cool, and some working lights:

Temperature sensor rework

A minor frustration that Dan Smith and Simon Calvert both identified before I got to the problem proper was that the build guide makes no mention of the fact that you have to earth the temp sender via the black and yellow cable shown below. I mentioned this in my day 7 post, and showed a picture of my sender fitted as I thought best. I actually used the screw thread on the bottom of the sender to locate into the plastic water pipe carrier attached to the rear of the engine. What you actually have to do is turn it upside down and then route it close enough to both of the connectors as per the picture below. For me this meant that Derek had to send a new J hose and the new earthing bracket and nut as shown. These parts are not provided, so it was impossible to see this coming.


Rear Bulk head carpet

The first thing I did was wipe down the inside of the car with a damp cloth and some surface cleaner. Then a dry fit of the rear bulk head carpet showed me that I needed to make two small cuts so that it would sit well over the rear tunnel. I then used some contact adhesive spray that had been recommended by others. I sprayed over both the back of the carpet and onto the bulkhead itself. The nozzle has three settings and it’s accurate to spray and avoid overspray. Where I had the odd wild spray moment later with boot carpet fitting, overspray can be cleared off with a cloth and some WD40.


The photo above shows the carpet stuck down and the start of the next stage, which is riveting the tunnel top plate down. I also chose not to apply glue to the rear carpet here in the sections lower than the tunnel. There is no need as the seats back into this, the carpet doesn’t flap around, and if I ever needed to remove the carpet, it would give you the ability to pull up from the bottom. The carpet covers the holes for the access to the bolts of the rear suspension mounts.

Tunnel top plate & rivets

The tunnel top plate is very easy, just a bunch of rivets to fix. I invested in a ratchet rivet gun which is a lot less effort than a basic one. Each rivet needs around 2-3 pumps on the handles, but these are almost finger tip effort compared to a standard “feel the strain and pain” ones in my opinion.

Knee trims

Well this is a painful job. I knew it was going to be, but after reading lots of other blogs, I still step into each job in positive mental attitude mode assuming that the others before me obviously didn’t do something quite right and I will prove how easy it actually is.

Well, quite simply, its a total pain in the backside. In fact lets me more clear. The LHS knee trim panel is impossible. The RHS one went in relatively easy, say 5 minutes of alignment and then tapping screws started to go in. The advice from others is that once you have lined up one hole at either end, stick a temporary rivet in this hole and then you can rotate the plate to get it aligned and jam a second rivet temporarily in this hole. This worked a treat on the RHS. After an hour of fiddling on the LHS I gave up and aligned it my way. Now its important to think about the fuse box cover and 12V socket carrier. This piece basically attaches to the LHS knee trim panel, so any non-standard fixing has an impact on alignment of this. I worked through and got everything floating and nicely aligned, got out my paint pen and marked up through the inner body panel holes onto the knee plate.

When I extracted the plate to look at where I thought the holes should be drilled, I was around 10 mm above the existing pre-drilled holes, and these were parallel to my paint dots.

So I had another go at trying to get the knee panel properly in place without DIY holes and spent another 30 mins cursing and not getting alignment. A cup of tea later and I wimped out, drilled new holes, and within 10 minutes had the knee trim panel in pride of place, with rubber trim all lined up underneath and the 7 self-tappers screwed in as below.


Carbon Side sills

The next job was to fit the carbon side sills, in effect a push fit over the edge of the body panel where your arms would rest if you didn’t have the doors or door arm rests on.

The assembly guide doesn’t quite say whether these should be positioned fully back towards the rear wheel arch, or fully forward towards the dash. They could do with being a bit longer to fit the complete width of the gap. In the end, I looked at how they would be attached (through pre-drilled holes in the inner skin and decided on a middle/middle approach.


The assembly guide provides a good image of the layout here, because the end result is that you have to trap rubber trim between the skin and the carbon sill. You need to drill through the skin holes to then drill through the carbon. Then fit the rubber trim and drill again to make sure that the rubber is pierced in exactly the right place, whilst making sure that the trim is lined up nicely.

Then its a case of riveting all of this together. If you have arm rests on your doors, then you need to leave 4 holes un-riveted for the escutcheon fastener (the silver item in the photo). I have temporality slotted it in place as a reminder. This will be aligned later and drilled out through a few of these holes, then riveted in place. You just cant do it until the doors are attached to the windscreen surround and then lined up properly with the other end of the escutcheon fastener.

Tunnel TopIMG_1822

The tunnel top un-bagging from its box was rather upsetting. Its in nearly perfect condition, but nearly is not good enough. Its been damaged at some point, possibly in transit. I inserted it temporarily, as you can see from the image above, but the rear face that rests against the bulkhead carpet has been bashed up. Underneath the top surface, its actually a very tough metal base and is simply too hard to band back into shape. And even if I could, there is a small “nick” out of the surface material in the same area. I contacted Derek and sent photos through to his email, and as luck would have it, Caterham have some in stock so I will receive a replacement shortly.

Fitting this was simple however. I didn’t un-peel the backing tape on the sticky pad near the gear stick as I will do this when the new tunnel top arrives. What you have to do is lift the handbrake up to its highest setting and then simply insert over. I screwed the gear knob on for a more finished look whilst I’m waiting. Its starting to look fab inside the car!

Floor carpets

I received two large almost rectangular shaped pieces of carpet, and these are for the floor underneath the seat. These pieces are shaped to fit a car without lowered floors, so I placed them inside the car and they were too big. I folded and pinched marks on the oversized carpet along one side to find the line for trimming, then used my Stanley knife against a long rule to cut the carpets down. Some contact adhesive was then applied and the carpets stuck into place.

Boot carpet

I then moved backwards to the boot area, where you receive lots of little shaped pieces of carpet, and they are to be stuck all around the inner skin of the boot and against the rear bulkhead. They all fit beautifully and again I got my contact adhesive spray out for this – I’m on my second can of the stuff!

I may have made a slight mistake simply by following the build sequence and assembly guide here. I didn’t think it through but a piece of carpet on each side covers 3 holes that are used (along with others) to attach the rear wheel arches.

Ideally, I think perhaps these should be fitted before the carpet is stuck over the nut and washer when the arches go in. However, the carpet would then not fit beautifully, and be really lumpy over the bolt ends and nuts. Maybe I have done it OK, and I poke the screw from the outside arch through the carpet, and terminate with a washer and nut that remain visible inside the boot. It would make more sense and make it easy to replace rear wings from an access perspective. Either way, thats what I’m doing, because the carpet is stuck fast!

Wheels on and car off its axle stands!

Final act of the day was an exciting one. There was no reason not to be a big kid, put the wheels on, take the axle stands down and get the car on the floor in the garage sitting on its own four wheels.

Even though I’m used to how low Caterhams sit, a few months of it up on axle stands means that you get used to that position, and the car seems amazingly low when they are removed. I pushed it backwards and forwards and made some brum brum nosies πŸ˜‰

My next build day will be focusing on the boot cover, which needs to go in before the seat belt harnesses. And then the seats can go in. If that goes well, I will start on the wheel arches, but lets not get too far ahead of myself.

I do have the whole weekend in the garage, as my wife and kids are off camping with some girl friends. I have to stay focused and not end up in a pub πŸ˜‰


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