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Episode V: The Rollbar strikes back

Updated: Jan 27, 2019

There have been many occasions during the build when I've concluded the build was simply impossible and it's lead me to feel my kit is a bit of a lemon. Fitting the track day rollbar was one of those tasks which at times certainly reinforced that feeling and then some.

Well I've after about 8 hours of finger wrecking, back breaking pain I've successfully installed the roll bar and looking back I can't help with tongue in cheek compare my experience to lifting an X-wing from a swamp on a distant moon. Indulge me here, I'm a child of the 80's, when Star Wars was great and Kathleen Kennedy hadn't turned it into her political pedestal. I can't help but feel there is some analogy here, me, expressing Caterham ask the impossible, whilst 'Master Derek' imparts some Jedi wisdom, it certainly reminds me of the conversation between Yoda and Luke over the recovery of Luke's X-wing which sank beneath the swamp water on Dagobah.

Life lessons from Caterham

I guess if you are new to the Caterham build experience and reading this, you're probably thinking what the hell is this bloke on! Then again I suspect if you are familiar with the build, you probably understand. If you're not much of a Star Wars fan you'll be equally bemused.

Let's get back to the build shall we before my limited audience presses the back button.

First up a quick recap. In November 2017 I attempted to fit the track day spec roll bar supplied with the car. At the time I couldn't align the bolts which feed up through the suspension turret. Eventually, I ended up with a cross threaded bolt hole and a written off roll bar. Caterham graciously agreed to send a replacement. In a bid to limit potential courier induced damage I had the roll bar shipped to my in-laws in the UK. The second leg to the Isle of Man can often be the cause of damage through harsh handling. The replacement bar remained at my in-laws until around a week ago when I journeyed across the Irish Sea to collect it. Once back home I opened the packaging only to find that the couriers had still damaged it, one of the end plates was bent through 90 degrees.

Caterham 7 roll bar boss
Courier damage bent boss securing plate

Great! I spoke to Caterham as soon as I could and expressed my concern, they again graciously agreed to send a 3rd. This time the bar was given some serious packaging, a box within a box and copious amounts of bubble wrap. Guess what, the couriers still managed to cause one of the rear tubes to poke through both boxes. It beggars believe what happens to a box during transit. Luckily there was no damage so, I could finally try a new roll bar on the car.

Caterham 7 Track Day Roll bar
Caterham 7 Track Day Roll bar

Excitedly I placed the new bar onto the car, inserting the boss into the recess.

Caterham 7 Roll bar
Roll bar added to the car.

Then getting under the car I could see we had the same problem the chassis hole and boss didn't line up. Derek at Caterham and also members of the Lotus 7 forum all warned me the bolts often don't align and can be tricky to install, but it is possible.

After hours of trying I have to say I wasn't at all convinced.

From what I understand the boss bolts which are M10x20 caphead bolts should go in first. Once the boss bolts are in, follow by adding the four remaining bolts, two M8 on top of the boss and two larger M10 on the rear tubes.

I started with the boss M10x20 caphead bolts at around 2 pm in the afternoon, I stopped for an evening meal which took about 2 hours, and eventually finished at 10:30 pm. It took forever, at the end my fingers were sore and my back equally as painful. I didn't want to insert the bolts with a socket or similar tool opting to use my fingers so that I could avoid any risk of cross threading, the problem was keeping sufficient grip outstretched and on the very edge of the bolt, quite a challenge and it eventually caused some discomfort.

After hours and hours of trying various approaches I succeeded, although even now it feels like sheer luck, a one in a million chance. The common approach suggested to me online was to engage minimal threads on one bolt, lift the boss from the recess and then 'jiggle' the bar whilst searching for the thread on the other side. I did this for hours, eventually ending up with what feels like only a quarter turn on the first bolt. Eventually though I did get a thread on the second bolt and managed to secure both. Obviously you'll need two people for this, one on either side lifting the bar slight up from the recess. I did observe just how offset the bar was when I finally got both threads engaged, I was convince the boss was too far across from the recess, but as I gradually engaged more threads the bar gradually sat down. The key aspect of this process is just how little thread is engaged on the first bolt, I spent a considerable amount of time backing that bolt out until finally the solution worked. If you are repeating the process, I'd recommend the least engagement possible.

Once the boss bolts were in and secured around 50% of the way up, I added the M8 bolts to the top of the boss, again about 50% and then the rearward bolts. The top M8 bolts went straight in, whilst the rearward bolts required a little brute force but they took less than 30mins to get through their respective brackets. You can see what is happening with the rears and there is plenty of play assuming you don't clamp the boss down. You just need to be more physical.

On review I do feel the alignment of the chassis hole on my car was off centre, I'm not sure if this is normal but it's clear if the hole was more central the task would have been easier, as the boss hole and chassis would have been closer allowing the bolt to pass through true.

Caterham 7 Build blog Suspension
First hole is offset, closer to the bottom right of the turret as shown by greater surface area of top left. Aligning to the left would have increased alignment with the boss behind.

The job is done, they just need final torquing, a job I'll do on the final spanner check. I truly hope never to need to remove those bolts ever again.

Final comments.

Suggestions via the Lotus 7 Club forum TechTalk and also from Caterham did include elongating the chassis hole, however I wasn't comfortable with this given the surface area onto which the bolt head had to clamp. Additionally I feared such a modification might go wrong resulting in the bolt simply pulling through. It was also suggested the bolts could be omitted, I understand the boss bolts weren't previously used, however I wanted to maximise safety and so continued until the matter was resolved.

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