Instrument Cluster Restoration, 300SEL - PeachParts Mercedes-Benz Forum

JamesDean · #1 04-15-2015, 10:19 AM

Good Morning All,

I just thought I'd share some photos of this instrument cluster I have been restoring. The cluster is from an 89 300SEL that is in Singapore. The cluster housing and gauges were in pretty rough shape. Click any of the photos to see the full resolution image.

Here is a link to the full album:
www.imgur.com/a/RxVjC

The housing had been modified to have better lighting but whenever I tried to fire it up it would trip my power supply's current limiter. Something must have happened to it.

It was initially shipped to me for odometer repair but I found nothing wrong with the odometer. All the gears were in tact and my testing showed that it functioned normally.

Video of Testing:
https://www.youtube.com/watch?v=oprsuTUlxHY

As part of my standard cluster refresh service I test all gauges, replace all capacitors, and re-paint the needles.

I also repaired the outdoor temperature display. I swapped the display portion of the unit on to the customer's electronics. However this revealed more problems with the circuit board as the output was nonsensical. So I ended up selling him a complete replacement unit:

However on this cluster, the gauge faces were particularly worn. The housing around the gauges was worn too. I suspect lots of sun, but not really sure.

I offered to replace the aged housing with something nicer. I figured that W126 parts are not nearly as available in Singapore as they are here in the states. A forum member on here came through for me with a nice housing from another 300SEL.

OLD:

"NEW":

After talking with my customer it was clear that he intended on keeping the car for a very long time and wanted to restore the cluster as much as possible. I wanted to offer him new gauge faces but have not had a whole lot of luck finding them.

I've now located two sources. The first (whitegauges.net) offers vinyl pieces that go over our existing metal gauges. Unfortunately they did not have anything that matched up with the metric speedometer of this 300SEL.

The other source, moman.pl, had what I needed, the 240kph speedometer face. MoMan gauges very well made and they are also plasma back lit which REALLY liven up the cluster and make it easy to see at night. I was quite pleased with them.

I showed photos of their gauges on the website to my customer and he approved. I placed the order and 15 days later a new gauge set was at my door. They are manufactured and shipped from Poland.

Installation is not overly difficult. I did have to remove all of the needles. The new gauges faces are stuck to the old one with some adhesive. The new faces have wires coming off them that need to be fed outside the cluster and connected to their inverter unit.

Here is an example of before/after faces:

The inverter unit takes 12V DC and pump its up to the 100-200V AC that is needed to excite the plasma back lighting.

I used a dremel to make small notches in the housing to allow the wires to neatly pass through.

I had to clear out this plastic piece so that the gauge could fully seat. You do not want to bend/damage the new gauge faces. The dremel made quick work of it.

The inverter needs to be fed 12V. This is ideally fed by the stock cluster lights circuit as they are controlled via dimmer. The gauges can be dimmed too. I found two unused solder pads on the speedometer circuit board and soldered wires to them. I also found some nice holes to pass the wires though!

I soldered my wires to the inverter inputs and then connected everything up with their splitter device. I ziptied wires together to neaten everything up.

JamesDean · #2 04-15-2015, 11:37 AM

I tested a few different combination of lighting:

Standard Incandescent Lighting, No Backlit Gauge Light:

Cool White LED Lighting, No Backlit Gauge Light:

Standard Incandescent Lighting, With Backlit Gauge Light:

Cool White LED Lighting, With Backlit Gauge Light:

I think that the end result is very nice. A definite improvement over what it arrived with...My camera does make the back lit gauge lights look a bit more harsh/intense than they are in person. I'm very pleased.

Hit Man X · #3 04-15-2015, 02:47 PM

Awesome work, Kris. Expect a huge box of failed MB and BMW bits for service soon.

TnBob · #4 04-16-2015, 12:41 AM

super job and so well documented.

pwogaman · #5 04-16-2015, 08:44 AM

Indeed.

JamesDean · #6 04-16-2015, 10:10 AM

Thanks everyone! It was enjoyable project.

If anyone is interested in having any parts of this restoration done to their cluster, feel free to drop me an email. I'm happy to do whatever you'd like.

The new gauges faces, are really sharp. I'm really impressed with them.

Elshad_1976 · #7 12-30-2021, 07:44 PM

Hello,
Thank you for sharing this upgrade project. It really looks very decent, namely not too much and yet up-leveled as if it is an authentic Mercedes Benz factory make. I'm considering to order from MoMan the kit. And I really don't want to install UV lights to light up the needles. UV lights in MB instrument cluster look nothing but a total crap. But your project shows that the needles are illuminated pretty enough. Therefore, would you please share what LED lights (technical data/brand) did you use to replace two incandescent bulbs on the top of the cluster. The only thing that I would do additionally is to light up the mileage digits and install chrome rings (exactly like on MoMan website). But in general, my congratulations - this is absolutely true style!
Thank you in advance for your help!

JamesDean · #8 12-31-2021, 12:42 AM

Quote:

Originally Posted by Elshad_1976

Hello,
Thank you for sharing this upgrade project. It really looks very decent, namely not too much and yet up-leveled as if it is an authentic Mercedes Benz factory make. I'm considering to order from MoMan the kit. And I really don't want to install UV lights to light up the needles. UV lights in MB instrument cluster look nothing but a total crap. But your project shows that the needles are illuminated pretty enough. Therefore, would you please share what LED lights (technical data/brand) did you use to replace two incandescent bulbs on the top of the cluster. The only thing that I would do additionally is to light up the mileage digits and install chrome rings (exactly like on MoMan website). But in general, my congratulations - this is absolutely true style!
Thank you in advance for your help!

I'm not a huge fan of the UV LEDs. I've used different brands/parts and they can look less crappy and much less obvious.

I like the bulbs from SuperBrightLEDs:

https://www.superbrightleds.com/moreinfo/miniature-and-subminiature-bulbs/194-led-landscape-light-bulb-5-smd-led-tower-miniature-wedge-retrofit-95-lumens/3305/6774/

You will need to clip off half of the leads so they match the sockets MB uses otherwise you'll short the bulb out.

--Kris