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speedometer will only go to 25 and then stop
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Supporting Member of 12/20
Picture of Paul And Jaime
I noticed yesterday while on a test drive that my speedometer will only go to 25 mph but no higher. all the other gauges work correctly. I checked the back of it and cable turns freely and I snaped it back in after checking and of course made no difference. Still 25 mph. What is some common things to check? Is there a way to convert these to digital? I love working on this thing, my wife can't understand why I work on the coach more than I do the house.
Posts: 140 | Location: Ky | Member Since: 10-20-2020Reply With QuoteReport This Post
Official Barth Junkie
Supporting Member of 1/23
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The old mechanical speedometers used a cable to drive the gauge. The cable was connected internally to a magnet. The magnet sits close to a shaft which is connected to the needle. The needle is spring loaded to return to zero unless the spinning magnet pulls it off zero. The faster the magnet spins, the farther the needle is moved up the speed scale. The indicated speed is the result of a balance between the force generated by the spinning magnet and the spring on the needle.

To get the correct speed, the gap between the magnet and the needle shaft must be correct. If the gap is too large, the needle will show a lower speed, if the gap is too small the indicated speed is too high. Oldtime speedo tuners would adjust the gap or the spring tension on the needle to get it right.

If the speedo needle bounces around it is usually due to binding in the speedo cable. Lubing the cable will make the needle more steady.

In your case, it appears the needle is sticking at 25 mph and above. Could be dirt or binding of the needle in the speedo housing. You will probably have to open it and clean it up. Not easy, as the case and face are usually crimped together.

Aftermarket gauges now are usually GPS driven. Very accurate and they eliminate need for the mechanical cable drive. I replaced the gauge on my 86 with a Speedhut GPS gauge. Worked very well.

I agree, working on the house is not as much fun, but our wives don't always think so! ROTFLMAO

"98" Monarch 37
Spartan MM, 6 spd Allison
Cummins 8.3 300 hp
Posts: 4993 | Location: Kalkaska, MI | Member Since: 02-04-2011Reply With QuoteReport This Post
Supporting Member of 12/20
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Ok thanks, I will remove the cable and pull the center and try to add some grease to it and see if that helps.
Posts: 140 | Location: Ky | Member Since: 10-20-2020Reply With QuoteReport This Post
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I am also a member of usa7s and a person there had a similar problem that was solved by magnetizing the magnet. as they do degrade over time. But for me a switch to GPS really makes sense. In fact it would not surprise me that there was an APP for your phone to do that. john
Posts: 79 | Location: golden valley, az | Member Since: 02-05-2009Reply With QuoteReport This Post
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Hello Paul & Jaime,
Several years ago our Breakaway had the same speedometer problems which you're presently dealing with and additionally our tachometer was glitchy as well, so we tried the greasing, the spraying, the splicing, & the magnetizing as well, with some success. However, on our way home, both gages quit working & finally we'd had enough. In the mountains of Central PA, not knowing one's ground speed & engine speed, is a big concern, made especially difficult with a diesel pusher like the Breakaway is, since one can't drive "by ear" very well.
Anyway, we followed Steve's advice(& others') & ordered both new units from Speed Hut. This wasn't exactly cheap but that was a couple years ago & the performance is impressive. In addition, we were able to chose the color & the font that we desired, the technicians were very helpful, and all this with a lifetime warranty.
The GPS system on the speedometer also adapts to any gearing & tire diameter changes which we had made on our coach. The only drawback that I could possibly see would be after a "Carrington Event". Of course in that case, whether one's speedometer worked would be the least of our concerns Hide

Good Luck,
Posts: 49 | Location: Central Pa. | Member Since: 03-24-2019Reply With QuoteReport This Post
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    Forums    Tech Talk    speedometer will only go to 25 and then stop

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