I was helping a friend (Dennis) with the carburetors on his MGB when something caught my eye.
I mean, it’s a beautiful car, so many things can catch your eye. But this one I really liked.
Dennis had power mirrors!
I hadn’t seen such a
thing on an MGB before, but I really dug the look. After some discussion, I went off to do some
research on how I could do the same.
This is that story.
Based on photos, I determined the mirrors were from a late
80s Mustang convertible. They’re proportional
to the car and have that great 80s look.
I found a set on eBay for the amazingly low price of $40. They even worked when I hooked them up to power. Of course, they were black and needed some
TLC.
I also needed a power
mirror switch. Dennis had his mounted in
the armrest, but I thought I had a better idea.
There is a brake warning switch in the MGB that in my opinion doesn’t
really do anything useful. I found a
switch for a mid-90s Miata ($20) that looked like it might fit in that
spot. After a little persuasion, it fit
like a glove. I even had 12v power and
ground at that location.
Of course, the mirrors aren’t made for an MGB. The mounting angle is very different. Dennis had his mounted farther down the door, which looked good, but it meant I’d have to drill holes and blank off the original mirror mounts. I was not keen on that idea.
Looking at how the original mirrors are mounted, there are
two holes into which the mirror base is inserted and then screwed into place,
held by friction. I decided that I could
design an adapter that would accept the mirror on one side and allow bolting
from the inside of the door on the other side, with an angle adjustment that
would allow the mirrors to sit level and be mounted in the original mirror’s
location.
So I did a little 3D modeling in Fusion360 and came up with
something pretty cool. After a couple of
prototypes were printed in PLA and adjusted, I sent them off to a printing
house to be printed in PETG (I do not have my own 3D printer… yet) and wouldn’t you know it, they fit
first try.
You can see the mounting holes for the mirror and the bolts for the door. I heat pressed in some threaded inserts into which the bolts fit, so the adapter is firmly held to the door. The angle adjustment is about 10 degrees. It turns out it needed to be more like 12 degrees, but I got pretty close. I adjusted the adapters with a sander and file.
Now that I had mirrors, I needed a wiring harness that fit
the Miata switch and the Mustang plugs. I
found wiring diagrams online and sourced the switch connector from an import house
in California. The Musting mirror plugs
went away and were replaced with 4 pin Molex connectors, of which only three
pins are used. I bought 18 gauge wire
and made a harness… and they work! The
left-right is backwards, but I think that’s okay – I couldn’t disassemble the mirrors
to try and swap the leads.
Now I had to make the mirrors the right color. My friend Mike helped me out and painted them
for me. Iris Blue, just like Alice!
Now the real fun began.
I took my bravery test and drilled a hole to allow the mirror wires to fit
inside the door. Since the hole would be
covered by the original mirror base, this is still a reversible job if I ever
wanted to do so.
The next big challenge was to actually get the mirrors
bolted in place. Of course, I had to
remove the door card and roll the window all the way up to even have a chance
at making this happen. There is ALMOST NO
ROOM to get your hand up into where the holes in the door go… so I got a bolt
through the door, then spun the mirror to get it to catch one thread, and then
could get the other bolt started and slowly thread them into the adapter
base. I was then able to get a 7/16”
wrench up in there and tighten the bolts.
This is really a two person job, at least the way I did it, but I
managed.
Once the mirrors were bolted into the doors, I needed to get
the wiring harness into the door and connected to the mirror. I couldn’t get the connectors through the
holes where the wires to the door would go, so I drilled a hole next to the
existing one on each side and removed the connectors from the wiring harness. I threaded the harness through the new holes,
into the doors, reattached the connectors, and hooked them up to the
mirrors. I’ll never get the wires out
without removing the connectors, but that’s okay. I also secured the mirror wiring so it wouldn’t
flop around inside the door.
After all of this, they still worked!
(The picture shows a test of the wiring, not the final connection.)
After buttoning everything back up, I admired my handiwork.
I love them. They
look like they belong and fit where the original mirrors were. They are not out of proportion to the car. Thanks to the wider mirror glass, visibility
is dramatically improved. I don’t have
to roll down the windows and reach over to adjust the passenger’s side mirror. They’re attached firmly and while they do vibrate
a bit at idle, they’re good at speed. I
am not worried about them coming loose.
I did one last thing to improve the character of the switch. I had a couple of spare switch bezels, so I did a little Frankensteining and made a bezel to fit over the switch. Now, it looks more like it was always there.
I really didn’t have to do this, but it was a fun little project! All told, it cost me about $120 for the mirrors, printing the adapters, the switch, connectors, and wiring.
I’m getting closer to my goal of building a ‘1985’ MGB, something still classic but updated to what might have been. Next on the list – cruise control for those long-distance drives to California. Stay tuned!
