Speedometer needle replaced, now speedo not working. Odometer works (1 Viewer)

[taoofbean]

UPDATE TLDR: Make sure you keep the weight of the new needle as close to exactly the same as the old needle and you are fine.

This story starts like so many cautionary tales, I had the idea to improve something that was working fine. Now it doesn’t work, s***.

My speedometer and odometer were working fine but the needle on the speedometer was old and melted looking so I thought I would refresh it and clean the gauge housing. I used two spoons, a scary amount of force, and popped the old needle off and replaced it with a nice hand painted new needle. It worked on the first test drive normally and now just sits pegged at zero.

1. The speedometer cable appears in fine shape and spins as expected when I drive around without the guide attached. I see the square cable and it rotates.
2. The mechanics of the gauge appears to be fine and the needle moves if in put an Allen wrench into back of the gauge and spin it.
3. The odometer continues ticking upward which is crazy if the odometer works but the needle stays at zero.

My guess is that the square speedometer cable is not inserted correctly into the socket in the gauge bit that is confusing because the odometer is still ticking. Any ideas? I would hate to learn I broke the speedometer mechanics in popping off that old needle. Just wait till you see my next post where I think I may have similarly broken the fuel /temp gauge in painting those needles.

 

[CruiserTrash]

@PVCsnorkel

 

[OSS]

A speedometer isn’t really necessary. It’s more of a crutch. It’s easy to gauge your general speed just by seeing stuff pass by. My first toyota pickup truck I had in 1980 didn’t have a functioning speedometer - and I drove it like that for 6 years.
1. If cars are passing you, you’re not speeding.
2. Of you’re passing everyone- you are.
I found having a speedo distracting on my next vehicle (FJ60). I would constantly glance down at it to check my speed-and I never really needed to.

 

[taoofbean]

EDIT: woke up this morning and was in the shower and it hit me, I think this is because the replacement needle is of course not the same weight as the original needle. The magnet/spring that spins the needle in the original likely is calibrated for the exact weight of the original needle and the new needle if it is not same weight (is heavier) will need more force so when I am driving around the neighborhood to test it, it is not enough to get this newer heavier needle off the peg.

I will take a drive on the highway with the new needle to test to see if it pulls it up. Additionally, I am going to remake a new needle that weighs as close to the original as possible. I just need to find a scale that measures in milligrams because the original needle is light, <1 gram. the new needle is about a gram.

After dabbling a few more times with gauges just sitting loose in the cabin to see if the work, my current thoughts on the speedometer is one of two things:

1. I somehow stripped the inside of the speedo where the cable inserts and it no longer spins the speedo assembly. Not sure how the odometer still works but that is a separate matter maybe not dependent on the speedometer cable. If I stripped it, that would explain why the cable spins as expected, the speedo reacts when I insert and turn an allen key and yea why it does not work when inserted together.
2. Or The speedo cable does not spin when inserted into the gauge. I am guessing this is not the case though because in can put my finger on the spinning cable while driving, safety first! And it keeps on spinning no problem.

My hunch is that I stripped the receiver on the back of the gauge.

 

[taoofbean]

Current goal is to make new needle weigh as much as old needle to test my current hypothesis.
I think I found the perfect needle material in the base of an incense stick. A little paint and it is going to be good as new.

 

[taoofbean]

So it is the weight of the needle that matters. Makes sense, I wasted 2-3 days of thinking trying to figure out how I broke the speedometer when what happened was I just neglected what seems obvious in retrospect. Replacing with a needle assembly that weighs as close to exactly the same as the original is key. I also lubed the gears and the moving parts while I had it apart.

I cut the base off an incense stick and painted it. Lightweight, perfectly straight was key.

Just for archival purposes in case you really need to know:

• .634 grams original needle and base
• 1.151 grams replacement needle from ebay. Too damn heavy and threw the whole thing off.
• .669 grams new needle made with incense stick and the original base.
  

 

[CruiserTrash]

So it is the weight of the needle that matters. Makes sense, I wasted 2-3 days of thinking trying to figure out how I broke the speedometer when what happened was I just neglected what seems obvious in retrospect. Replacing with a needle assembly that weighs as close to exactly the same as the original is key. I also lubed the gears and the moving parts while I had it apart.

I cut the base off an incense stick and painted it. Lightweight, perfectly straight was key.

Just for archival purposes in case you really need to know:

• .634 grams original needle and base
• 1.151 grams replacement needle from ebay. Too damn heavy and threw the whole thing off.
• .669 grams new needle made with incense stick and the original base. View attachment 3348206

Plus I'm sure you now have the title of only Land Cruiser in the world to have an incense stick speedometer needle. Think about it: not another single one on planet earth. You've forged into new territory here!

 

[cheeese]

If you get it past 85 mph does the needle start smoldering?

 

[OSS]

Congratulations on the discovery!

 

[ChaserFJ60]

I was restoring my old speedo for fun and also broke the needle. I resin printed a new one that popped into the original socket. Have not tested it though. If there are any abnormality's I could add/subtract weight on the model to be 3D printed. It makes sense as how weight would effect the speedo and not the odometer as the Odometer is connected mechanically but the speedo is connected via magnets.

Good find!

 

[taoofbean]

If I get it past 85 mph and survive with the original 2F engine, someone call Guiness Book of World Records.

 

[taoofbean]

Double, ignore