Monday, 31 August 2015

Rivnut Refiitting Guide for Rear Wings

After all the toing and froing of the leaking gearbox dilemma, I think it's sorted! No leaks (yet) on my garage flooring, so it's happy days once again... So... I decided to take the Caterham to work on Friday to enjoy the weather before the heavens opened for a miserable bank holiday weekend's worth of rain!

The car was all good and running well.  Not the longest of journeys, but good to get out again, as it has been a while... I think nearly two months!  At the end of the day and time to leave, I had a few things still to finish off, at which point my business partner came up and said he'd crashed into my car whilst reversing out of his space - I thought he was joking as he's the type to muck around like that...

Anyway, it wasn't a joke and yes, the car had some damage!  I didn't freak out (which was surprising) as it looked worse than it was...   Lee (my business partner) was very apologetic as you'd expect etc etc, and I assessed the damage.  I'd say it looked more like a 'slow clip' of the wing than serious damage and it appeared that the rivnuts had been pulled from the skin behind the wing, with only the exhaust mount being a little bent.  I taped the car up with some low tack tape, and drove it cautiously home.
Caterham with taped wing after a minor incident with an X5!
Caterham with taped wing after a minor incident with an X5!
I rang Caterham Midlands to see what they suggested and it turns out Simon Lambert was up there helping out and I spoke to him... Simon was extremely helpful, went through the issue with me and suggested it may be a fairly easy fix (which I thought was the case too, but I wanted to double check with them).  He pointed me to this threaded rivnut insertion tool on amazon and said I needed some 5mm aluminium rivnuts... With a little persuasion he posted the rivnuts to me first class, I ordered the rivnut tool from amazon and everything arrived the very next morning!  Well done Caterham and Amazon!

I had some karting in Llandow to attend to over the weekend, so it wasn't until this morning that I could fix the car.

So onto my guide for replacing a wing and refitting rivnuts
I've put this guide together for my car (an R500 Duratec) please read the full guide before you start, and note there may be variances between the vehicle you are working on and this guide.

As a number of people had advised me in the past, Caterhams are quite susceptible to losing their rear wings... On track days, hitting cones and business partners reversing into them in their X5's!  Some people have suggested using plastic screws to hold the wing in place, which means the plastic screw snaps cleaning removing the wing from the rivnuts - which is great for racing, but not so practical on the road as you could do more damage to the paint on the wing (when it hits the tarmac) than the wing just pulling the rivnut away from the skin of the car.  So I've decided to stick with the metal screws.

Firstly, get yourself a large coffee and a bacon sarnie - a great way to fuel yourself for a couple of hours in the garage!
BLT and Costa before the rivnut refitting
BLT and Costa before the rivnut refitting
Below is a picture of the wing, you can see it's pulled away from the skin of the body, with the rubber piping lose, and also the exhaust looks somewhat askew.
Wing pulled away from the body, wing piping lose and askew exhaust.
Wing pulled away from the body, wing piping lose and askew exhaust.
What you need to do to get started is get the wheel off.  So using one of the rear jacking points (I put the jack on the cross section underneath the fuel tank), jack the car up sufficiently to remove the wheel.  Put an axle stand in place if you need to, but I trust my jack as it has a locking mechanism.

Then remove the rubber grommet (left of the picture below) and you should be able to pull the light connector block through the hole and separate the two connectors.  Then using an 8mm spanner loosen all ten fixings for the wing - start at the bottom and finish at the top, so the wing doesn't fall away from the car unexpectedly and cause further damage.
Remove all ten wing fixings, from top to bottom and remember to disconnect rear light wiring.
Remove all ten wing fixings, from top to bottom and remember to disconnect rear light wiring.
With the wing removed you can see that the front five rivnuts have pulled through the aluminium skin of the car.  The protruding aluminium around the rivnut holes will need to be lightly tapped back into place.
Wing removed, five rivnuts pulled through body skin.
I wanted to completely check the wing for damage, so I laid it on some cloth on garage floor so as not to damage the paint.   I know of other Caterham owners who've clipped their rear wings, with the GRP literally tearing apart, so I was hoping the wing would still be intact.  The wing was completely intact on the underside, which is testament to the additional strength of the carbon fibre over GRP wings.
Underside of wing intact, testament to the strength of carbon fibre over GRP wings
There was a very slight crack of the wing on the leading edge, which just needs some carbon epoxy left to cure overnight, a rub down and a touch of paint.  I'll get 'my mate Dave' at Daytona Coachworx to do this.
Very slight crack in leading edge of wing
Very slight crack in leading edge of wing
With the wing removed and checked over, it was time to push the protruding body skin back into it's original location.  I found the best tool for this was a medium socket extension, covered in a microfibre cloth, tapped lightly with a rubber mallet.
My bodywork repair contraption
My bodywork repair contraption
The skin of the body is very soft, so using my 'hammering contraption' I very lightly tapped the protruding body skin back to it's original state.
Rivnut holes tapped back to their original state
Rivnut holes tapped back to their original state
Here is the threaded rivnut insertion tool and the rivnuts that Simon Lambert from Caterham very kindly posted to save the day.
Threaded rivnut insertion tool and 5mm aluminium rivnuts
Threaded rivnut insertion tool and 5mm aluminium rivnuts
Having never used a threaded rivnut insertion tool before, I had to read the instructions!  It's really easy to use once you get the hang of it.  Open the handle, put the correct sized mandrel and collar into place, and screw the rivnut onto the end.
Threaded rivnut insert tool with 5mm aluminium rivnut ready to go
Threaded rivnut insert tool with 5mm aluminium rivnut ready to go
And the first one goes in... Really easy, put the rivnut in the hole and squeeze the tool... Don't squeeze too hard though as you can ruin the thread of the rivnut!  You can easily feel when enough pressure has been applied, and it doesn't 'snap off' like a standard rivet, you need to unscrew using the knob on the back of the tool to remove.
The first rivnut goes in
The first rivnut goes in
 Repeat for all the rivnuts you need to replace, in my case it was the leading five.
Leading five rivnuts replaced
Leading five rivnuts replaced
Then starting from top to bottom, very loosely replace the fixings for the wing.  It's worth loosely fitting the wing, with about 5mm of gap, so that you can then fit the rubber piping.  I find that working the piping from the top of the wing is the easiest way to fit it, but for tightening it's worth adjusting the piping to fit, then tightening a few fixings at a time to get a good fit. These fixings do not have a torque setting, so just nip them up to hand tight being careful not to over tighten.
Wing replaced, rubber piping in place, and rear light reconnected.
Wing replaced, rubber piping in place, and rear light reconnected.
Don't forget to reconnect the rear light connection, and replace the grommet.  Refit and torque the wheel, and then lower the car and the job should be complete!

I also had to remove the exhaust, slightly bend the exhaust bobbin mount back, and then refit the exhaust to finish the job, but the wing is now secure and looking like new again.
Rivnuts refitted, wing securely fastened, with exhaust re-alligned too - job done!
Rivnuts refitted, wing securely fastened, with exhaust re-alligned too - job done!
Hopefully I'll be able to have some trouble free use of the car over the next few weeks, I think Snetterton is calling!

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