Dear All,
I would like to remove my Mk2 speedo to clean it up hoping that will improve the illumination. I have already removed the steering column and drivers seat for other reasons so I can lie on my back looking behind the dashboard.
I‘m finding it impossible to reach the top knurled securing nut. There are a couple of small things in the way which I could remove to help but their removal is not mentioned in the manual.
Are there any good tips to remove the speedo? Any experience cleaning it up to improve the illumination?
How are the 2 illumination bulbs fixed? They don’t seem to be simple pull out versions like the 3 warning bulbs.
Thanks in advance,

 

remove the tach first ? then you can insert hand and wrist through tach opening to reach speedo fixings.

the rubber o ring behind the speedo gauge frame is probably "welded" or "melted" to the wood finish by now, so you will need both hands to rotate the gauge and unstick it anyway.

if you use a higher watt bulb to get more illumination, chances are the green or blue plastic bulb dome inside the gauge will melt if not already melted. Sometimes just cleaning the bulb is all you need.

the bulb sockets should come off by pulling or pushing it to one side or the other, they are "spring" forced into the hole.

 

Thanks for your tips Jose. I managed to remove both gauges after first removing the horizontal small plate which seems to be there to protect the link from the Inhibitor Switch to the gear select control rod from getting entangled with wires. To remove the rev counter (tacho), I needed to tip the top edge of this gauge rearwards into the car to free the bottom edge where the clock is located. Neither points are mentioned in the workshop manual.
The speedo has blue bulb domes. Neither cleaning the dome nor using a new bulb improves the illumination. The LED bulbs which I bought do not fit inside the dome.
I‘ve removed the front ring and window from the speedo and seen that the light from the 2 illumination bulbs is reflected at the inside wall of the housing through a narrow slot around the perimeter of the dial face. This housing wall is white for a small part but mainly grey or black. Is this normal? It certainly doesn’t help the illumination. I’m considering to try white paint to increase the reflection. Have you any experience with this?
Thanks in advance,

 

 

Dave I have only opened the tach which might be somewhat similar.
To improve lighting I have used mirror glass, ( map light S type ), or reflective aluminium tape ( map light XJ-6 ).
But that would be impossible in the speedo.

How about chrome paint instead of white paint ?

 

I would listen to Jose & use a reflective paint. Virtual chrome is available in rattle cans.

 

My ideal instrument illumination at night is the dimmest that allows me to see the readings - a little brighter than old Jaguar at full power. And the colour should be yellow, possibly edging into orange or green, but definitely not blue. I realise our old cars tried to achieve blue light and nowadays bright blue is popular with some current models, but it's not for me. I'd go for yellow LEDs and chrome paint to scatter the light.

 

White paint improves the illumination but mainly at 3 and 9 o’clock near to where the illumination bulbs are located.

I now assume the original paint pattern seen on my photo above was aimed to achieve a uniform illumination around the whole circumference. So I would not recommend the simple use of a single paint colour.

The source of the problem is that the domed filters become opaque with age. Hence there are 2 possible solutions:
- leave dome filters and use warm white LEDs (these radiate a similar spectrum to filament bulbs but radiate more light lumens so more light will pass through the filter)
- remove the dome filters and use blue LEDS or filament bulbs according to colour preference

Hope that helps others. I’m still considering which way to go and will play around with the clock in the meantime…

 

I didn't want to suggest it but in both my speedo and tach the domes were burnt and cracked, so I just eliminated them and kept using higher wattage bulbs.
Not a lot of difference color-wise, more incandescent yellowish like Peter said.

My car has a 3-way OFF-DIM-BRIGHT switch that works fine except there is not much difference between DIM and BRIGHT. Dash candy if you ask me.

Trouble with LEDs is that you can't dim them and I did not want to mess with adding electronic stuff or defeating the switch.

 

Better Car Lighting have some dimmable LEDs for dashboard illumination. The other option would be to rearrange the circuit so dim switched only some bulbs.