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| | | | Joined: Sep 2007 Posts: 84 'Bolter | | 'Bolter Joined: Sep 2007 Posts: 84 | I recently rebuilt my speedometer for my '53 3100. I put a mechanism from an 80 mph unit in my 90 mph unit because the shaft on my 90 mph unit was broken where the needle attaches. These units are the same whether it's an 80 mph vs. 90 mph...right? I assumed the faces would be the only difference. The numbers on the speedo mechanisms had all the same numbers cast into the housings. The reason I'm asking is because my speedo operates smoothly but it doesn't begin to move until I hit about 10 mph. I have it set at zero. I begins registering when I accelerate to about 10 mph and then routinely reads between 10-15 mph less than my actual speed. Anyone know how to fix this or what's going on? The unit seemed to spin freely at the bench.
Thanks
1953 3100 | 1958 3/4-ton NAPCO
| | | | | Joined: Sep 2008 Posts: 125 Wrench Fetcher | | Wrench Fetcher Joined: Sep 2008 Posts: 125 | here in L.A. we have a few speedo shops that specialize in these kind of problems.They dont chargr much and have yet to be stumped by anything I have thrown at them. I know you can obtain correcting gears, but I thought all head units were the same as far as ratio goes. I've had a bunch of speedo's that won't register until 5-10 mph, but they usually are fairly accurate after that.
Who is John Galt?
| | | | | Joined: Jan 2008 Posts: 493 Shop Shark | | Shop Shark Joined: Jan 2008 Posts: 493 | You could try holding the shaft and moving the needle on the shaft clockwise 15 mph. It sounds like in may have been turned during the rebuild. A hand held GPS comes in handy for finding out which way you need to move things. If the error is off by the same amount through the range just move the needle. | | | | | Joined: Jun 2004 Posts: 8,597 Riding in the Passing Lane | | Riding in the Passing Lane Joined: Jun 2004 Posts: 8,597 | First compare the odometer with the mile markers on the freeway or mark off a mile distance with your car. If the gearing is right then you need to correct the needle like Neilroy says.
They say money can't buy happiness. It can buy old Chevy trucks though. Same thing. 1972 Chevy c10 Cheyenne SuperIn the Gallery Forum | | | | | Joined: Aug 2007 Posts: 1,859 Grumpy old guy playing with trucks, cars, and boats | | Grumpy old guy playing with trucks, cars, and boats Joined: Aug 2007 Posts: 1,859 | I would send it in to the speedometer shop in Milwaukee, or D&D Speedometer in the twin cities. For low $ they will give it a clean bill of health and have it calibrated properly.
The problems we face today can not be addressed at the same level of intelligence we were at when we created them - Albert Einstein Or with the same level of $ - Me
| | | | | Joined: Feb 2006 Posts: 1,867 Shop Shark | | Shop Shark Joined: Feb 2006 Posts: 1,867 | If you screwed with the spring that the needle shaft sits on, in any way, shape or form itll never be accurate. You can blow on these things and tweak them, thats how sensitive they are.
Jeff | | | | | Joined: Oct 2006 Posts: 9,671 'Bolter | | 'Bolter Joined: Oct 2006 Posts: 9,671 | Hey Scott, ya got a name of that speedo shop in Milwaukee?
Denny Graham
Sandwich, IL
Denny G
Sandwich, IL
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