Please note that there are (at least) three types of steering wheels used in C5 I & II:
4109 EK, 'honest' plastic steering wheel
4109 FN, 'looks-like-fake leather' leather steering wheel, with stitching but no padding
4109 EX, real leather steering wheel, has an easily noticeable soft padding under the leather (unlike 4109 FN)
This repair method applies to 4109 EX and 4109 FN.
This repair is done with the Furniture Clinic Leather Colourant Kit. A small kit is well sufficient for a steering wheel. I've used the Black HC colour with matt finish; that is slightly darker than the original coating. However, with the matt finish the result doesn't look at all bad in daylight. I have a feeling that Furniture Clinic's standard dark grey GRY08 might not be dark enough.
I recommend watching Furniture Clinic's excellent instruction videos before doing anything - they'll describe the procedure very well, although they're not about steering wheels:
How to Restore a Leather Car Interior
Leather Colour Change, Part 1 and Part 2
2-3 days will be needed for this process, so plan the timing accordingly unless you have a spare steering wheel at hand.
- Disconnect the battery, remember to let BSI get into sleep mode before disconnecting.
- Remove airbag with due respect (a large flathead screwdriver is needed) - the two connectors behind the airbag come off when the locking pins in the middle of them are prised out with a small flathead screwdriver.
- Remove the steering wheel, a Torx 50 key is needed.
- The wiring of the horn can be removed if desired, but not necessary.
- Let's start with lots of warm water, a brush, a Scotch-Brite pad and soap (for example Le Chat or washing-up liquid). That combination most often removes a good portion of the very thickly applied waxy coating. No need to waste precious Leather Prep (which evaporates very quickly and smells absolutely horrendous) for the dirty work itself. If the wheel has leather glued above the airbag (there are 2 models of these, the other one does), that area is probably pretty ok and the coating does not need to be removed from there. So determine which area to save in its original state.
- Let the wheel dry thorougly (at least overnight).
- Carefully protect the rest of the wheel (ie. areas not to be recoated) with masking tape etc. If the area above the airbag is ok, carefully mask the intact area in order to protect it from the pretty nasty solvents we're about to use.
- Now let's remove the remaining coating using Leather Prep (which includes acetone and ethylene acetate, nasty smelling stuff) or acetone (which does not smell THAT horrendous) as instructed by Furniture Clinic. Then a good sanding with 600 and then 1200 grit sandpaper to ensure the surface is nice and smooth.
- Now a good wiping with Alcohol Cleaner as instructed by Furniture Clinic. The wheel should now look like something like this:
- Once the solvents have evaporated, a couple of layers of the leather colourant are to be spread with a sponge, ensuring there's dye everywhere on the wheel. Observe for potential rough spots and sand down as necessary. Unlike in the instructions by Furniture Clinic, I've applied thin layers of leather dye with a sponge until there's a nice uniform coverage of dye and the colour looks even. Saves leather dye and airbrush propellant. Allow every layer to dry well before adding the next one. Now an appearance like this:
- Once again check the surface for anything you'd want to sand down before spraying the final layers of leather dye. Sand with 1200 grit paper as necessary.
- Spray 2-3 thin coats of leather dye (allow drying between them, a hair dryer will speed this up); don't forget to shake the bottle well, filtering the dye is also a good idea. A protective mask for yourself is a good idea. Once again, sand down irregularities as necessary.
- If the wheel is of the model having the large leather area above the airbag, now remove the masking covering it. Sand down the seams between the old and new coating in order to make them unnoticeable. Clean the old coating are with Alcohol Cleaner, then new dye can be sprayed on top of it too (so we'll get a nice uniform colour).
- Once the leather dye has dried properly, spray at least 2 thin coats of glossy Super Seal. Note that the leather dye is pretty sticky and will gather dust; carefully remove any dust before spraying the Super Seal. Super Seal runs very easily, be careful! Allow every layer to dry properly (apply hair dryer if desired). Once again, sand down any rough spots with 1200 grit sandpaper, and remove any dust before spraying the next layer.
- Now it's time to to apply the final leather finish. I've used matt finish with a tiny bit of glossy finish mixed into it. Probably Furniture Clinic's Semi-Matt Finish would be about the same and pretty close to Citroën's original; no need to mix anything. Remember to shake properly, and filtering the finish is recommended. 2 layers should be quite enough. Once again, beware of running finish. Allow to dry for 24 hours, and the steering wheel is ready for use. After 7 days, I'd recommend applying the Furniture Clinic Leather Protection Cream. From then on, regular cleaning with water and microfibre cloth should be quite enough.
- Refit the steering wheel and airbag & reconnect battery, allow BSI to start up properly.
A couple of before/after photos of a recently refurbished steering wheel which was initially in pretty awful shape: