Hi
I hope this post may help others. I searched long and hard, but could not find any posts relating to the MK 2.5.
I wish I had taken pictures, only thought about doing this write up afterwards…durr
Having just bought my 2003 MX5 1.8 MK 2.5 Montana, and exported it to France where I now live, I have to change the headlights to a LHD pattern to conform and pass the CT (French MOT).
Looking at new prices (£400-500 a pair), I decided to see if I could modify the existing units. I have successfully done this on my Jaguar X Type previously.
After removing the units, split them in half. I used a hot air gun, others have baked them in the oven for around 20 mins gas mk 5, to melt the black mastic type substance which holds the 2 halves together. My oven wasn’t big enough! There are a couple of screws to remove and 3 clips to detach also. Don’t try to bend the clips back until you have warmed the plastic up, as they are liable to snap. There are plenty of online videos showing how to open up this style of headlight.
Once open, adjust the adjusters so that you can access the two screws to the rear of the dipped beam pod, which hold the reflector to the pod. These were very tight. Support the pod from underneath with blocks of wood to stop the adjusting mechanism from becoming detached during the process.
Once the reflector is free from the pod, you can access the screw which holds the beam plate in position. Remove the beam plate from the headlight unit.
The top of the beam plate is shaped like this for RHD —___ but needs to look like this for LHD ___/—. On the Jag, the beam plate was flat. On the Mazda, it’s a 3D curved shape, which made the construction of the replacement beam plate a bit trickier .
I made an accurate template from paper, and then used this to make a replacement beam plate from a sheet of galvanised tin.
The next step was to grind the original beam plate flat at the top. The replacement beam plate was then fixed to the original with 4 rivets. Its position is critical, so take you time. I used a couple of small clamps to hold it in place whilst making the fixing holes. A quick dab of high temp silicone was used to fill the centre of the rivet holes and the bottom of the joint between the old and new beam plate. This will stop any light bleeding through and spoiling the beam pattern. I then sprayed the assembly a matt black.
Reassembly is a direct reversal of disassembly. Take great care to keep everything clean.
Before I started I marked the position of the beam pattern (RHD) on the garage doors with masking tape. This gave me a reference point for adjusting the headlights one reinstalled. I subsequently took the car to my local garage to have the headlights properly adjusted using the CT (MOT) machine.
The original RHD beam pattern looked like this ___ ___, the new LHD beam pattern looks like this / /
Including removing and replacing the headlights, it took me about 6hrs, inc tea breaks.
Saved a few hundred quid, and the process is totally reversible should the car ever go back to the UK.
If anyone needs help with this, send me a PM.
Hope this helps others.