Gauge Cluster Teardown and Rebuild - Beware, Pic Heavy!

This thread is going to follow along as I refurbish a gauge cluster for my 79. Hopefully it will be helpful for other members as a reference for information with questions they may have or pictures of things they need help with. Please post any pictures and offer your knowledge you have. This may be “my” cluster, but it is “our” forum.

My truck originally came with the gauge package (RPO Z53), replacing the idiot lights found on others. The one gauge it does not have, however, is the one I most wish it had, a tachometer. This was an option above and beyond the gauges. This is a picture of my current gauges….. (not a good one either)



My goal is to keep this truck “looking” as factory and/or original as possible. So I started looking for a tach gauge cluster. Went to a popular auction website only to see them going for $200, and of course in un-tested condition. Ummmm….. no thanks. Months later I was perusing CL and happened upon none other than a tach gauge cluster, for $25. Pictures looked good (for the price anyway), and an hour and half drive later it was mine……




Some of the main reasons I actually got this was for the tach specific housing, and the fact that it had part of the wiring harnesses for both the main gauges and the tach. Those two reasons alone made it worth it to me. I actually went into this planning on the tach not working and buying a new one that LMC is offereing. We will however cross that bridge when we get there.

Time to crack this baby open. Six screws are located around the perimeter. They hold both the clear lens and the large metal trim piece to the housing. Remove those and pull the lens off, but not the metal piece yet. You need to remove the gear indicator first. Mine only had the main piece with the gear numbers on it and the spring.





This is after I pulled the lens. Bugs on the speedo. Been sitting a while…

Before we go any further I need to clarify something. Due to various factors and condition of some parts, I thought it to be better to buy a donor cluster. I got a nice clean donor locally for cheap. So if you notice some pictures don’t look like the same cluster, they probably aren’t.

Back to it. Pull the lens, gear indicator, and metal trim piece, and you have this (this is the donor cluster now)…………





The gauges are held primarily by the screws that are obvious. After you pull the screws the gauges still won’t fall out because they are also being pinched by metal clips from the back side. It is these clips that interact with the printed circuit on the back side of the cluster to send the electric signal to the gauges. Here is a picture of said clips…..



You also have these cool colored plastic pieces that are used for the bright lights indicator, turn signals, Brake/Fasten Belts, and 4 Wheel Lock/Choke. There is also foam pieces that go around them.





Remove screws and pull the gauges. Simple. Now the front side of the housing is pretty bare…. And dirty…..

Now time to get things off the backside. Bulbs are fairly self-explanatory. Turn counterclockwise the appropriate amount and pull. The clips are more involved, but still pretty simple. I used a pliers to squeeze them together and push one side through the housing at a time.





Bare housing…





All my pieces and parts…..



















This is how I organized my screws and little parts. Stick them through a piece of cardboard! I have a bad habit of getting a lot of pieces laying around from different projects, and forgetting what goes to what. I thought this would be smart.

It was at this point that I realized I have a lot of rusty parts, like almost all of them! The metal trim piece especially bugged me, the gauges themselves were more rusty than I realized, the lens was nasty, and I think I ripped the printed circuit beyond use when I was removing some of the light bulbs. I thought I would try to see how clean I could get stuff before I do anything else.

Word of caution!!! The lettering on the gauges do NOT like any type of liquid! Even straight water! I got a paper towel damp, not soaking wet, and started clean the dirt off the tach. HOLY CRAP! I am smearing the paint! Be VERY careful if you need to clean gauges!

Decided to do it right and remove the needles. I had read they can be a pain. You need to go slow. Some said to use a fork. No….. not me. Why use a metal fork when a plastic golf divot repair tool will be easier on the gauge. Slowly work it under the needle and gently start prying. That’s how I did it….







Another word of caution, if the needles do not want to come loose easily, you might not want to go to far. I was having a tough time with my speedo and broke the shaft the needle gets pressed onto.

It was after breaking the speedo needle that I sat back and evaluated my options. I decided to get a donor cluster for parts. Found one locally for a good price….



I was looking for basically all the gauges if possible (sans tach), good metal trim piece, and nice rust free clips for the gauges. Got them all.

New vs. old parts…..









I found this interesting. On clusters with a blank bottom left gauge, it is just a plastic cover over the hole. I did not know that. If you didn’t either, now you do.







Wedge type bulb, 168 looks to be stock, and socket…



Here are the differences between a tach cluster housing, and a “regular” gauge housing. Big obvious area is gone for the tach and bulb and gauge clip locations are different. Tach housing on bottom…..

That is where I stand now. Both of them tore apart ready to be put back together as one good cluster. Things I need to do before putting it back together….

-Hook up tach and see if it works.

-Paint housing. I was thinking of painting the housing white for better refraction of the bulbs. Those that have done this, did you use a glossy white, or satin/flat white?

-Paint metal trim piece. Going to sand and repaint the front black. The backside I am going to paint the same white as the housing, for the same reason.

-Undecided as to what to do with the gauge faces. I thought about deviating from stock, but not going white. I was thinking maybe a stainless face color? Or maybe green to try and match the rest of the interior? Stay stock?

-Paint needles all the same color. OCD, nuff said.

-Decide on bulbs. I know what your going to say…. LED. Maybe, still exploring options.

You can paint the housing white or 'chrome' to brighten up the backlighting. However, it ends up being a bit yellow tinted light, which is probably the reason for the really light blue color of the housing. Personally, I think the lighting is fine if everything gets cleaned, front and back.

VERY nice.

Just a word of advice, the speedometer needle unscrews. Just rebuild one myself and the odometers are quite the pain in but to change numbers on. I tore mine down and rezeroed it when I completely rebuilt truck. Take apart a junk one first for sure.

bucket said:

You can paint the housing white or 'chrome' to brighten up the backlighting. However, it ends up being a bit yellow tinted light, which is probably the reason for the really light blue color of the housing. Personally, I think the lighting is fine if everything gets cleaned, front and back.

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Good to know, thank you. I had not come up with a conclusion as to why it was painted light blue. I know the research went into it and they probably did it for a reason. Other guys have painted theirs white, but I had never heard reports of a different tint of light. I was going to look into what kind of bulbs are available in that size also.

And I agree... most of the time the stock lighting is fine. On all the newer vehicles I never run the gauges full on bright, I always end up dimming them half way. On my Monte the lighting could be better, but that is an older vehicle like the truck.

RetroC10Sport said:

VERY nice.

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Thanks!

towjoe said:

Just a word of advice, the speedometer needle unscrews. Just rebuild one myself and the odometers are quite the pain in but to change numbers on. I tore mine down and rezeroed it when I completely rebuilt truck. Take apart a junk one first for sure.

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Oh, that explains it! Now I know! Do the rest of the needles just pull off? I was messing with the odometer a little bit too. My truck is about to turn 100,000 miles, so I am hoping to have this new one zeroed out and ready to go by then. Then I can claim actual miles on the odometer and it be true!

Thanks for the feedback guys!

really time consuming, but it's worth it. If you paint the inside of the black plastic cover with chrome pait it will make a world of difference.

Green79Scottsdale said:

I found this interesting. On clusters with a blank bottom left gauge, it is just a plastic cover over the hole. I did not know that. If you didn’t either, now you do.

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Mine has a red lens that lights up when im cranking it

Damn that was filthy...strong work. This is a project on my short list, definitely keeping eye on this thread.


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Driver4r said:

Mine has a red lens that lights up when im cranking it

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I have seen that, but I thought it was just on the clusters with idiot lights. Does yours have the idiot lights or the gauge package?

8T6K5 said:

Damn that was filthy...strong work. This is a project on my short list, definitely keeping eye on this thread.

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I follow all your action pretty closely! Love what you have done with the Blazer! This would be a very nice upgrade for you.


I decided to find a paint that would match the original. The closest I came up with is a Rustoleum Aqua. It is a satin finish paint, so I also grabbed a gloss clear coat to go over it. When I got it home, it really doesn't match the housing itself. However..... it matches the back of the other gauges and the back of the metal trim plate pretty nicely.





I figure since I have it, I am going to use it. Couple of reasons why...

All the "pure" or "ultra" white type bulbs have a blue coating on them. But they all shine without a hint of blue. I have Silverstars in our van and can attest to this. Since I do not plan on doing LED's in my cluster, I am hoping I can get away with using the standard bulbs in it and still achieve adequate lighting conditions.

It really is easy to tear it back apart and change my approach if I want.