NOTE: The gauge cluster and gauges shown in this blog are from the Mercedes W116 and 107 chassis. The W123 instrument cluster is very similar, but there are some differences in the disassembly process of the housing. The W123 specific housing restoration will be covered in a later article.
There are numerous ways to refinish faded or dirty indicator needles on a gauge and clean the gauge face, but great care must always be taken to avoid making matters worse. The following step-by-step is simply my preferred method for the process. Only do what you feel comfortable with based on your particular circumstances and experience level.
Take your time and properly prep any surface to be refinished, but always be aware of what can and can't be used as a cleaning agent! Some cleaning agents will destroy, while others will do nothing. It is best to start with the least aggressive cleaning method and work your way up as needed.
For this project, I recommend having the following "tools":
Distilled Water
Cream of Tarter
Construction Paper
Masking Tape
Petrolium Jelly
Cotton Swabs
Microfiber Cloth
Rubbing Alcohol
Hobby/Model Spray Paint (I used Krylon Short Cuts - Glow Orange)
STEP 1
For the purpose of this blog, we will begin with the gauges already removed (For instructions on gauge cluster removal from dashboard, visit my blog "W123 Ignition Switch and Lock" posted Feb. 18, 2017. A subsequent article will cover a complete disassembly of the cluster housing for cleaning.
STEP 2
DO NOT do proceed to the following steps and consult a professional If gauge face finish is cracked, chipped or is in any other manner deteriorating!
Typically the gauge face should only be lightly dusty and need just a gentle wipe with a microfiber cloth. If however the the printing (numbers etc.) or background paint is grungy, the following will likely help to clean the surface quite well.
First, mix about 1 level teaspoon cream of tarter (available in the spice or baking section at any grocery store) in a small container and add just enough distilled water (must be distilled) to make a paste—it should not be runny.
WARNING: Always test along very edge of gauge face that is not seen when installed. Apply adequate amount of the cream of tarter paste to the face surface and gently agitate over the entire surface with fingertip. DO NOT allow paste to enter the gauge mechanism. Remove paste with an unused microfiber cloth that is slightly dampened with distilled water until all traces of the paste is gone and lightly buff for final stage. Should any dirt remain, attempt one additional cleaning. If still no success, it would be advisable to contact a professional in the field for further assistance. Generally however, the cream of tarter paste works excellently should it even be needed. FYI, the cream of tarter method came on recommendation from a jeweler who restored vintage clock and watch faces. I have also cleaned a number of gauge faces using this method with excellent results.
STEP 3
Throughly cover entire face and sides of gauge with construction paper and tape. All seams in the construction paper must be sealed and the sides of the gauge must be sealed as well. When spraying, the smallest gap will allow spray paint to penetrate and potentially ruin the finish. At this stage, also clean needles gently with rubbing alcohol. Lightly dampen cotton swab with rubbing alcohol and gently rub needle until no traces of dirt can be removed. If color is just being removed, surface should be sufficiently clean to paint. Allow to air dry for about 5 min. before painting.
STEP 4
Now coat needle centers liberally with petroleum jelly. Apply to top and entire edge—any where you do not want paint to remain. Be careful however, not to touch the needle with any petroleum jelly as it will cause paint not to stick. Photo below shows gauge ready for paint.
STEP 5
Spray needles from all angles using very quick passes from 6-8 in. away. DO NOT over coat needles. Paint will cover needles very quickly. Be sure however to examine your work closely from all angels. Check for even coverage before removing masking. If a spot was missed, DO NOT attempt to just spray paint the missed area. Spray the general area as before, to keep an even coat. Allow to dry for about 5 minutes.
STEP 6
After about 5 minutes, use a clean dry cotton swab and gently rub needle centers to remove paint. Do not touch needle as they may still be tacky and attract lint particles from the cotton swab. As you can see, the paint is easily wiped away, leaving a perfectly clean surface. When the paint is completely removed, moisten a clean cotton swab with rubbing alcohol and wipe down needle centers to remove all traces of grease. Any remaining grease will attract dirt over time.
STEP 7
If you are spraying needles in low humidity as I was, the spray paint can tend to begin drying on the way to the surface, causing flecks of paint on the edges as shown by the yellow circles. Should this occur, use a toothpick and very gently run it along the effected area to remove. Wait however until the paint is fully dry to do this.
STEP 8
Take a final look at the work and you are done. For any lint that may be on the face of the gauge, use low pressure shop air to remove.
NEXT STEPS
I highly recommend at this stage to disassemble and clean the gauge cluster housing. Don't put your beautiful gauges back into a dirty case. My next blog article will focus on the cleaning and overhaul of the housing. If you're going to do it, do it right!
You can see what a difference a cleaning and repaint of the needles can do. The photo below is of the gauge in step 3, now ready for installation. You will also notice from the photo in step 1 how faded the needles were after 42 years. These particular gauges are from my 1975 Mercedes 450SL but the process of cleaning and painting is identical for the W123 and many other models.
