Click on image for the lowdown. 
====
| | | Forums66 Topics128,068 Posts1,055,882 Members48,428 | | Most Online14,466
Apr 26th, 2026 | | AD Chevy Trucks  Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
| | THANKS!
For helping keep this great
old truck web site
on the Internet for over 30 years! and not clogged down
with Ads!  Again, thanks!
| | | | Joined: Aug 2014 Posts: 213 I have more zippers then a pair of cargo pants | | I have more zippers then a pair of cargo pants Joined: Aug 2014 Posts: 213 | Who do people recommend to rebuild their speedometer and change the gauges to 12volt?? Or is there some kind of “kit” to do them yourself… thanks.. joe
~ Joe
Donate Blood, Plasma, Platelets and Sign Your DONORS CARD. The Life You SAVE Might Be Someone You Know and LOVE.
Two possibilities exist: Either we are alone in the Universe or we are not. Both are equally terrifying. ~ Arthur C. Clarke | | | | | Joined: Oct 2021 Posts: 6,771 'Bolter | | 'Bolter Joined: Oct 2021 Posts: 6,771 | Contact Jim Carter trucks.
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
| | | | | Joined: Feb 2016 Posts: 1,987 'Bolter | | 'Bolter Joined: Feb 2016 Posts: 1,987 | A shop near me could probably tell you what is the best approach, Bob's Speedometer.com, Howell Michigan. They have been in business a long time and did a quick calibration for me with no charge when I dropped in to talk to them.
1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy
| | | | | Joined: Mar 2014 Posts: 4,483 Moderator, Electrical Bay | | Moderator, Electrical Bay Joined: Mar 2014 Posts: 4,483 | Hi Joe,
Can you help us a bit? What year truck do you have? Some gauges might be mechanical and if they're working will need only refreshing (you can find decal templates I donated at the top of the Interiors section). Happy to tell you more about this procedure. Also, some of the 6v gauges may be fine without converting to 12v. Also, you can see where I've converted the AD speedometer into more/less a drop in GPS speedometer that looks very much like original and is designed to work on 12v. Sort of depends on how much you want to do yourself.
~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
| | | | | Joined: Mar 2014 Posts: 4,483 Moderator, Electrical Bay | | Moderator, Electrical Bay Joined: Mar 2014 Posts: 4,483 | This should take you to some of the speedometer work I did. https://tinyurl.com/5ay46h9r
~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
| | | | | Joined: Aug 2014 Posts: 213 I have more zippers then a pair of cargo pants | | I have more zippers then a pair of cargo pants Joined: Aug 2014 Posts: 213 | My truck is a 48 chevy, that I need upgraded to long tube (and stay mechanical) oil and temperature gauges and make everything 12 volts. And have the speedometer read 80 or 90, in black Hi Joe,
Can you help us a bit? What year truck do you have? Some gauges might be mechanical and if they're working will need only refreshing (you can find decal templates I donated at the top of the Interiors section). Happy to tell you more about this procedure. Also, some of the 6v gauges may be fine without converting to 12v. Also, you can see where I've converted the AD speedometer into more/less a drop in GPS speedometer that looks very much like original and is designed to work on 12v. Sort of depends on how much you want to do yourself. My truck is a 48 chevy, that I need upgraded to long tube (and stay mechanical) oil and temperature gauges and make everything 12 volts. And have the speedometer read 80 or 90, in black
~ Joe
Donate Blood, Plasma, Platelets and Sign Your DONORS CARD. The Life You SAVE Might Be Someone You Know and LOVE.
Two possibilities exist: Either we are alone in the Universe or we are not. Both are equally terrifying. ~ Arthur C. Clarke | | | | | Joined: Feb 2000 Posts: 5,206 'Bolter | | 'Bolter Joined: Feb 2000 Posts: 5,206 | The only gauge on your truck that's electrical is the fuel level, a voltage reducer will take care of it. To extend the bourbon tube on the water temp, BOW TIE BITS used to do them out of Wichita KS. Jim Carter likely knows someone that does it if they don't do it themselfs.
The speedometer can be cleaned as DIY project if you take a little time be careful with it. My '37 works really good with just a cleaning, it's going on 90 years old now. I calibrated it using a variable speed drill motor I set it up in a vise. Using a hand held mechanical tachometer used for small engines, I set the drill to 1000 rpm. 1000 rpm is the industry standard all speedometers are set to to read 60 mph. With the drill at 1000 rpm, the speedometer read 70 mph. I simply pulled the needle off moved it and kept trying till it read 60 mph @ 1000 rpm. At slower speeds its slightly off, and above 60 its slightly off, but neither is off so far I will get ticketed. I don't even notice it being off, I mostly follow traffic speeds anyway. Odometers are gear on gear driven, they will always be correct providing the input rpm from the transmission is correct. The speedometer needle is magnetic driven, and as long as the magnet is still good, the speedometer should work as long as its clean and lubricated.
Amp meters don't care about voltage, the amps, and amps is amps no matter the voltage.
Oil pressure is mechanical, a good cleaning and lube is all it needs.
New decals are available and are easy to apply. | | | | | Joined: Mar 2014 Posts: 4,483 Moderator, Electrical Bay | | Moderator, Electrical Bay Joined: Mar 2014 Posts: 4,483 | I'm not certain the "stick on" decals come in black, but I probably could alter the template I made to have a black background. I just matched the original brown background all these trucks seemed to have used when I did it and set it up for use with the GPS speedometer I created.
One suggestion: if you have been using 12v (or if 12v was ever used with your fuel gauge), please don't worry about a voltage reducer until you see how accurate your gauge is with a known good sending unit. The sending unit is very important and there is some pure junk being sold out there. The hourglass shaped permanent magnet that makes your fuel gauge work changes magnetic properties once you feed 12v to your gauge and based on what I've been told it may only take a few hours to a couple of days to alter the magnetic field permanently.
What I saw was interesting...the fuel gauges when used with 12v self-alter their properties and once they do, they'll not be accurate with 6v any longer. So if you reduce 12v to 6v (or 8v which is what many of the reducers out there accomplish) you may not help things as much as you hoped. I made a voltage reducer maybe 7 or so years ago which is the only one out there that is adjustable. The idea (and it worked fine) was to get a full tank of gas, install the reducer and then adjust it until your needle was right at full.
~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
| | | | | Joined: Jul 2020 Posts: 148 'Bolter | | 'Bolter Joined: Jul 2020 Posts: 148 | I used Speedometer Service in Colorado Springs to put on a new needle and clean/repair the gearing so the odometer works and the needle doesn't shimmy. I did not ask for the paper decals and left my faces as is. Speedo has worked great since then with no trouble for 3 years. Their number: +1 (719) 332-5323 | | |
|
|
