Sinclair C5 Restoration – Part 3 – Rebuild


In this video the C5’s parts get a thorough clean up. Some of the metalwork is sanded and re-sprayed. The chassis has come back from the power-coating company and is given an inspection, and the C5 is put back together again. Along the way I replace some worn out parts such as the tyres, brakes and a wheel bearing. The finishing touch is applied by way of new decals for the sides and wheels.

Clean up

The body shell gets a thorough clean. On the C5 Owners Facebook forum, new owners always ask – what product is best to clean the C5 with? The usual answers are as follows:

  • Cillit Bang (spray cleaner)
  • Cif (cream cleaner)
  • Magic Eraser (Magnum Force cleaner with magic eraser sponge)

I tried Cif and Cillit Bang. I couldn’t see a massive difference between the two products. I started using a brush (a back cleaning brush which was only £0.80 from Morrisons). However, this wasn’t shifting some of the in-grained marks. When I switched to a green scouring pad this really helped shift the marks. So the scouring pad is more important than the cleaner. I wouldn’t use this on the lights though, as it would likely scratch the clear plastic.

I used micro fibre cloths to rinse and dry off, helping to absorb the water and clean off that last bit of muck.

I would recommend using rubber gloves –  I didn’t to start with and after a few hours cleaning, my hands felt slightly rubbery for a few days.

The front wheel trim had been spray painted with white paint. To remove the paint I used nail polish remover (containing acetone). This took about two hours of patient cleaning with a cloth. The main bodyshell and wheel covers are made of polypropylene. This is compatible with many solvents, but always best to Google or try a test spot rather than risk melting the plastic if you’re trying another solvent.

For the smaller items (bolts, bearings, chain) I used white spirit. I did this outside in a washing up bowl and used a toothbrush to clean off the muck and old oil and grease.

I also used white spirit with a cloth on the wheels to shift the final layer of muck.


The chassis had been handed off to a local powder-coating firm. These companies are quite numerous and you should find several in any large town. They often do car parts and industrial metalwork. I requested quotes from three firms, but only one smaller firm got back to me, so I used them. I think they were used to one offs such as people handing in domestic radiators and railings etc. The big firms likely wanted large quantities (despite saying ‘no job too small’ on their website). It cost £84 (inc. VAT) and I’m really pleased with the result.

The chassis has some tapped holes and these need to be masked or bunged before the chassis is ‘bead blasted’ (a milder form of sand blasting) and then powder coated (covered in powder then put in an oven for the coating to form). The powder coating firm should take care of this.

My chassis had some light rust and marks. It wasn’t a bad case by any means. However, it now looks amazing – brand new. I know it isn’t on show but when working on the machine it is a pleasure to look at and should hopefully help the C5 along to another 30 years of life.

There was still rust to deal with on several smaller metal parts:

  • Stearing stem
  • forks
  • light switch bracket
  • front brake caliper
  • rear location frame

I sanded them with 240 then 400 grit “wet and dry” paper. I did this dry. The front forks took some 120 grit sandpaper to get the old black paint off – infact I think they may have been coated rather than painted as it was much harder remove.

Then a quick clean with white spirit to remove dirt and loose material. I then applied a few thin coats of grey primer which I bought from Halfords. I know you could probably get it cheaper / better from elsewhere, but the shops are very convenient.

It is better to apply more light coats than risk the paint running and you’ll have to sand of the drips and start again. I applied four coats of gloss black once the primer had properly dried.

I bought some lacquer to toughen up the surface. However, when I used fine grit wet and dry paper to prepare the surface, it stripped the black paint, so I gave up. I’m not sure if this was a result of my poor technique or poor paint. But the finished result is good enough 😉

I ran out of black paint when I came to do the switch bracket. I bought some smooth finish Hammerite black spray paint. I’m told this is tougher paint, and if I was starting again I would probably use this instead of the Halfords gloss black paint.

The rear location frame wasn’t rusty, but I gave it a couple of coats with the black spray paint after a very light sand to freshen it up.


The rebuild process is largely the reverse of the tear down – see my last video and the other page on this site for the detailed step-by-step process. However, there is some extra information required when re-assembling, and I stopped to discuss any replacement parts that were being used, and set up the brakes:

1) The forks are attached to the chassis along with the steering bar. To get the steering bar back on, use a rubber mallet (or mole grips and a block of wood to press the ball back onto the joint).

2) Front wheel goes on with new inner tubes and tyres. These were Schwalbe ‘Big Apple’ tyres which have added suspension to help smooth the ride as it is a bit harsh in the C5. These tyres have a ‘correct’ orientation for the tread pattern – in the video I got the front wheel the wrong way round. The direction of travel is marked on the side of the tyre.

3) Front brake – new cables

4) Body shell goes on

5) Fresh grease is applied to all of the caged bearings along the way.

6) Steering bar goes on, and the front brakes are set up. Use the cable clamp bolt to set the course tension.

Then use the screw at the top of the forks to set the fine tension. You should be able to move the brake blocks away from the forks. Then lock the position of the screw using the nut.

7) Rear brake. This is adjusted in a similar manner to the above. First, offer up the wheel and ensure that the wheel is locked when you apply the brake. Use the nut and cable clamp to set the course tension, and the screw and locking nut to set the fine tension. As the brake pads wear you will need to adjust this again.

8) A new lid for the Control Box was sourced from eBay. I found a faulty but complete Control Box for sale, and used this as a source of parts.

9) The motor goes back on (this will be serviced in part 4). The large gear goes on, followed by a new drive belt. The motor is asymmetrical on its mount. This means that as you rotate it, the centre of the gearbox moves close to the axle.

You can use this fact to help get the belt back on.

Rotate the motor until you can get the belt on. Then rotate it the other way to increase tension in the belt.  I used a wider 18mm belt rather than the usual 15mm belt, as this is supposed to help reduce wear on the gearbox teeth.

10) The left hand rear wheel goes back on. This is straight forward but make sure you get all the washers in the correct place.

11) The right hand wheel goes on. Here I struggled with the arrangement of the bearings. When I took it apart, there were two bearings together in the inner cup. I’ve learned this is incorrect and doubtless was the cause of the failure of one of the bearings. Mr. Snarsky confirmed the correct order of things, and the wheel was re-fitted. I used a new caged bearing, and also a special tool for holding the cone nut in place whilst the outer locking nut is tightened. This was sourced from eBay and is also a nice piece to have as all C5’s would have originally came with this tool kit. Below shows the correct assembly steps:

12) Fresh oil was applied to the chain

13) Boot goes on

Final Polish

I used Autoglym ‘Bumper and Trim Gel‘ on the lights, pedals and interior grey plastic. This really brings back the colour and adds shine.

The pod was sprayed with Simoniz ‘Back to Black‘ and then polished with a cloth. This helped to restore the black finish to the plastic.

Fresh Decals and side stripes

Fresh decals were applied to the front and rear wheel trims. These are orange reflective pieces. These reproduction decals were purchased from eBay and fit perfectly.

I was unable to obtain 20mm wide reflective tape for the side stripes. Instead I bought 50mm orange reflective tape (the sort with hexagons in the design) from eBay, and cut it down to 22m with scissors.

Since publishing the video Leigh got in touch to suggest that you should not cut the tape at the ends – but rather leave some extra tape and fold it back on the inside of the C5.  This reduces the chances of the tape pealing off. This sounds like a good suggestion as the tape I bought isn’t as sticky as the stuff that came off (it was very hard to remove). It certainly wasn’t original 3M brand tape, rather some cheap imitation.

I did’t replace the front ‘C5’ grey decals – these were in good condition. Reproduction versions of these can often be found on eBay if needed..

Next time…

The fourth (and final) part will be an investigation of the vehicle electrics. I thought this worthwhile given that the C5 was billed as a pioneering electric vehicle. I’ll also be showing a motor service, and fit a safety wiring loom and a fresh battery, as well as trying to fix the intermittent issue with the pod cable.

Parts list

Here is a list of all the parts I have replaced on the C5 along with supplier and price (as 2018):

  • Chassis – powder coating (local firm) £84
  • Drive belt (400-5m-18 HTD) (eBay) £11
  • Orange 50mm reflective tape (eBay) £2.50
  • Decals (wheels) (eBay) £10.45
  • Schwalbe 16 inch (x2) and 12 inch (x1) AV3 inner tube (eBay) £22
  • Schwalbe 16 inch x 2 inch “Big Apple” tyres [50-305] (Baldwins Cylcles on Amazon) £22 each
  • Schwalbe 12 inch x 2 inch “Big Apple” tyres [50-203] ( £12
  • Brake cables (cut for Sinclair C5) (eBay) £13
  • Brake blocks (BMX bike) (eBay) £4
  • M6x25mm black bolts and M6 “mudguard” washers (CPC) £8.10
  • Bike calliper bolt assembly (eBay) £2
  • Sinclair C5 tool kit (original) (eBay) £29
  • Control Box (original, faulty) (eBay auction) £12
  • Autoglym “Bumper and trim gel” (Halfords) £10
  • Simoniz “Back to Black” bumper shine (Halfords) £5


There is of course lots of useful information on the internet for the Sinclair C5:

  • Exploded diagram and parts list – in the original Sinclair C5 Owners Manual:
  • Unofficial Sinclair C5 Service Manual
  • Service Engineer training slides

What I couldn’t find was a step-by-step disassembly guide. This was one of the reasons I decided to film the project in the first place. There were some good videos on YouTube, and hopefully I’ve now supplemented this with my own videos. I took my disassembly guide and created a step-by-step guide from this, which you can print out and take to the workshop. I’ve updated this with issues and errors as some parts were incorrectly installed when I first took the C5 apart. Take a look at the “part 2” webpage on this site.


Once again thanks are due to the folks on the ‘Sinclair C5 Owners’ Facebook group. Charles provided many tips and a new bearing and washer. Sam Rowell’s eBay store provided many parts including the excellent reproduction decals. Leigh got in touch with some tips on securing the motor bracket and spotted that I had fitted the front tyre on the wrong way round, and Paul Grice provided details of a missing motor washer. And others provided much inspiration and stories to keep me motivated, so thank you all.

2 Replies to “Sinclair C5 Restoration – Part 3 – Rebuild”

  1. Hi Dave, great videos, really informative. I’ve cleaned my C5 with cif , and then buffed it up with Auto Glym Super Resin Polish from Halfords, and it looks good.

    Looking forward to your video on the electrics.

    All the best

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