I'm working on building my '59 f250 and I wanted to know if I can easily rollback the odometer to 0. I'm literally building it from the ground up, scavenging used parts from old rigs.
Just thought it would be cool to set it back to zero when I finally get it fired up and drive it.
wanted to ask before I ruin my stock speedo.

 

To reset a mechanical odometer it must be disassembled, the number cylinder turned back manually and reassembled. The individual digit cylinders all ratchet to each other so each time one reaches 0 it turns the next highr place one digit. You'll have to play with it a bit to find the "secret" for aligning it to the number you want it to display, kinda an easier version of rubik's cube. It's not a real difficult job if you work carefully and on a clean work surface. I'd suggest laying a clean towel down on the bench so should you drop a small part it doesn't go bouncing or rolling away.
My father had a nice part time job a number of years ago working for a major car dealer, resetting all their used car odometers back to zero. Back then it was not illegal to alter the milege as long as you rolled all of them all the way back. He could take one apart and leisurely reset it on the kitchen table in about 15 minutes once he had the cluster out of the dash.
Forget about the old wives tales about running it backwards with a drill in reverse or putting it up on blocks in reverse gear or similar nonsense, it doesn't work.

 

I did it to mine. I can't explain how to do it here, point for point, step for step. But is it is easy once you have it apart. You will see how once you have it apart.

 

Alright so I guess I just have to tinker with it.
I know it doesn't work to drive in reverse(Ferris Bueller's Day Off).

Would it work to put it on a dremel or other highspeed tool and try to run it forward till it rolls back to 0? Not sure how they are geared so don't know how long it would take?

 

I did it that way when I was in my teems and didn't pocess a reversing drill. I cut an old speedo cable to chuck in the drill. If I remember correctly I gave up because the drill was very slow and I didn't have the patiance at the time,lol. A high speed dremel may be the ticket. I'm also not sure that when they are spun over the 99,999.9 if the numbers line up because of the gearing so to indicate that the actual milage is correct, you know an indicater that only the dealerships were supposed to know about and not the general public.

 

It is real easy. You take the odometer assy out of the speedometer. Each wheel has an arm that is held by the mount that they are in. When you remove the assy, you can turn the wheels to zero, line up all the arms and put the assembly back in. Takes less than 5 minutes other than the time to remove and replace the speedometer. I still do it on restorations (just my own cars now) Anything that is older than 1980 does not matter to the law anyway, but an old vehicle does not have the extra digit it would take to show how many times it went over 100K miles......

Another take is to turn all the wheels to 9, then let it turn over to zero on your first drive. After a tenth of a mile, you can watch it turn over to all zeros......

Alan

 

How do you get the bezel off the can, without ruining it?

I wouldn't try the Dremel method, bound to end badly and realistically, if you could spin it to 60 mph, think how long it would take! Even at 100 mph... Likely to wear it out.

 

The dremel that is. Yep, that's the falacy with the drill etc method. Max speed the speedometer can go is ~ 100 mph, so for every hour you spin it you only advance it 100 miles. Would take 1000 hrs (41.6 24 hr DAYS!) to advance from 0 to 100K. Turning it in reverse won't work, the odometer/speedometer doesn't register in reverse, and you'll likely ruin the cable turning it backwards for very long. There are usually tabs holding the back of the instrument housing to the bezel around the edges. Occasionally there may be a couple screws, but they typically hold the individual instruments to the rear housing, not to the bezel. Take them out only if necessary.

 

My dremel plugs in and I think it spins at 30k RPM. I don't know how it's geared but I hoped this would run it at maybe 1,000MPH and if I had everything clamped up it would be done in a little less than 2 days(it's on 61k now).

Now that I think about it that would probably wear something out going that fast for that long.

 

Sorry, but no matter how fast you spin the cable the max speed of the speedometer cannot be exceeded.

 

I agree with AXracer on this. It would take forever and you are probably going to wear something out. I would just take it apart and do it and while you are in there clean it up and give it a light lube inside.

 

Are you sure?
I would think the odometer would be directly geared to the cable so the faster it spins the faster the numbers roll, regardless of what the speed needle might be doing.
The gauge goes to 100MPH and I would assume the needle would wrap around a little and maybe eventually stop but shouldn't the numbers roll proportionately to the cable speed no matter the speed. Can't believe it stops counting at speeds over 100MPH

 

The speedometer has a magnetic drive it is not directly coupled to the cable.