A few snagging issues…


Drivetrain Vibration

I have had a few issues since driving my car after completion. The most serious of which was a vibration that could be felt through the chassis, through my hands and the seat of my pants. There is a lot more detail I have provided about this via this BlatChat link, including testing other cars with vibration analysis iPhone apps.

For some time I thought it was caused by the Mazda gearbox resting on the chassis rails. It’s a wide box and only just fits in the gap. I did fabricate some spacers to fit under the gearbox mount (out of M14 spacers, with the edges filed down to fit the narrow shape inside the gearbox mount). This raised the box about 3 mm, enoguh to ensure that the gearbox was not resting on the left hand side chassis rail. Before I did this it was definitely resting and this would definitely go some way to explaining the vibrations I was feeling. But it wasn’t the only problem.

In he end, BaT suggested replacing the engine mounts, just in case they weren’t working as intended. They were definitely working, as I had tested vibrations on different parts of the car using an engine stethoscope. However, after BaT replaced the mounts, the rest of the vibrations eased up.

I now think that I have a normal working Duratec engined/Mazda gearbox combination Caterham. Still not as smooth as a K series, but more than good enough.

Brake Fluid Reservoir

My other issue is with the brake fluid reservoir. Basically on its first real outing, my car leaked fluid over the scuttle base on which it is mounted, an some of this fluid seeped over the edge of the car and has stripped paint from the edge (the bit that the bonnet sits on). This is really frustrating because I had not overfilled, and the cap was tight.

After asking others, quite a lot of folk are aware of a design flaw, and this is a small gap in the rear of the cap. This is covered by the rubber o-ring, but there has been some change in recent times and Caterham now supply a very thin o-ring. With the cap on tight, the thin o-ring does not supply a strong enough seal. In fact the cap tightens against its own lip as opposed to against the thickness of the o-ring.

Caterham, via Derek and BaT came up with two potential resolution options. Firstly, it’s a known issue and other solve this by being supplied with a “race cap”, which provides a perfect seal, but doesn’t provide any sensor outputs to the dash. So in effect, it won’t leak, but you won’t know you have lost your brake fluid elsewhere in the system until you crash. I don’t see this as a solution.

The second option, which I am currently trying is to “double up” on the o-rings. Derek sent me another brake fluid reservoir with another equally thin (and therefore badly designed) o-ring. I have taken the o-ring from this and am using now double the thickness by stacking the o-rings in my original reservoir. It’s currently working, as I have had no more fluid leaks.

However, Caterham, via BookaTrack do not see fixing my paint as a warranty issue. I had this report back a few weeks ago, and I have since been back to BaT and ask them to go back again. I find it astonishing that a known flaw with a brake cap that causes paint damage is not warranty repair. I’ll update the blog when I have an answer!

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