[C2] Speedometer Rebuild Help

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Dec 10, 2017 | 08:20 PM

RJMerc

Thread Starter

Racer

Joined: May 2017

Posts: 293

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Speedometer Rebuild Help

Hey guys, need a little help with my first project of the off-season. I'm on the first day of my gauge cluster refurbishment project. I have several issues I want to address including; very foggy gauge lens that need cleaning from the inside; replacement of all light bulbs and fixing the odometer and trip odometer which are not working at all.

After pulling the cluster out and disassembling the gauges, I think I've found the issue. The second worm gear (see speedo gauge blow up) is completely worn out. All other gears move freely, but the first worm gear doesn't engage with the worn out second worm gear.

I've found the part on Zip Corvette, so clearly it's a replaceable item, but I can't figure out how to remove it. It is a solid piece that seems to be placed in a solid cast housing. Even if I were to be able to remove the first worm gear, it seems that the pins on either end will still hold it in place.

Any ideas on how I might remove/replace the second worm gear?

Thanks very much,
Rick

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Dec 10, 2017 | 08:56 PM

buns

Safety Car

Joined: Feb 2006

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Use a small punch to drive out the gear in the direction of the yellow arrow. This will dislodge the gear retainer (blue arrow).

Dec 10, 2017 | 09:09 PM

RJMerc

Thread Starter

Racer

Joined: May 2017

Posts: 293

Likes: 74

[QUOTE=buns;1596153291]Use a small punch to drive out the gear in the direction of the yellow arrow. This will dislodge the gear retainer (blue arrow).

Wow, thanks. Worked perfectly. Once I replace the gear, should I use a little thread sealer to keep the retainer in place?

Thanks very much for the help!

Dec 12, 2017 | 01:54 AM

BWT

Instructor

Joined: Oct 2008

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Be advised that replacing the 2nd worm gear is a temporary band aid. The first worm, or magnet needs to be replaced. If one is worn, the other is too.

Dec 12, 2017 | 01:48 PM

buns

Safety Car

Joined: Feb 2006

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Not always. My 2nd worm was worn out but 1st worm was pristine.

Dec 14, 2017 | 09:08 AM

BWT

Instructor

Joined: Oct 2008

Posts: 207

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The second worm shown is slightly worn. It is not the original gear so it had been replaced. The magnet shown is the original type and does look good. If the odometer stopped working with these gears it is likely due to wear in the lower hole for the second worm, in the frame. The hole being worn allows the second worm to move away and disengage from the magnet, or first worm. It is not going to happen that a second worm would wear out, and the first worm would be like new. Think of a ring and pinion, or a Tach drive gear in the distributor.