Speedometer reset

[whutdidyousay]

ok, I looked and can't find anything specific enough..... I wanna reset the mileage on a 69 speedometer when I find one..... anyone know how to do this?..... hook it to a drill?..... I just don't wanna blow it up....
also what do I need to do to take it apart so I can repaint the indicator lights?..... seems like all the ones I have seen of any year are white or pink now.
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'68 bug (Sadie)

danke meine Freunde

I'm tryin to build a dream one piece at a time, just bear with me.

[glutamodo]

First of all, you cannot repaint the lights. Those are pieces of colored plastic that have faded, and will need replaced. Depending on what year your speedometer it, you may be able to get to these "gels" as they are called without dismantling it. The bulb holders may unscrew and if they do, there may be a rubber holder for these gels. Alternately these may be glued directly to the metal face of the speedometer head. If that bulb holder is riveted on, then you'll have to take the speedometer apart to get to it. To do that you carefully pry the cover off of it - the chrome ring around the lens is crimped onto the metal case of the speedometer. Then you can remove the two screws holding the mechanism of the speedometer to the backside of the case and lift it out.

Do not mess with the needle, unless you want to open a whole 'nother can of worms as far as throwing your calibration off. But you can bend the metal tab that holds an intermediate shaft with gears that turn the odometer numbers, which will allow you to pull one side up far enough so you can roll the odometer to read whatever you want to. Sometimes you don't even have to bend anything, just press the axle pin that those intermediate gears out. Then get the numbers lined up to wherever you want them, make sure they all "lock" together lined up, then bend that tab back and you're done with that. If you get the gears installed wrong they won't advance properly so you had best to check that before you reassemble.

As for the "gels", WW sells plastic strips you can use:

http://www.wolfsburgwest.com/cart/DetailsList.cfm?ID=111957000

But if you can find colored plastic elsewhere you can use that too. If you have a box of Pendaflex file folder tabs lying around somewhere, the green ones, doubled up, work pretty good for the turn signals (and oil if your speedometer is old enough that they still used that color for it) As mentioned before, they either glue to the back of the face or are held in a rubber cap that fits under the bulbholder. Oh, if you use file divider tabs, or other colored clear plastic sheeing, get a sheet of like ultra-fine 1000 grit sandpaper and "roughen" up the plastic before you cut them up and fit them, that way they won't be completely clear. I forgot to do that last time I did one, a 1968-style speedomer in my baja, so I now "see" the bulb in there, especially on the turn signals:

-Andy

[bushi]

Please be careful about altering the mileage on your odometer if you're in the US. There is a law called the Federal Odometer Act that makes tampering with odometers illegal. Here's a link with some info:

http://www.thecommondenominator.com/cl080999.html

[whutdidyousay]

as far as legal issues I live in Oregon and the DMV said I can do whatever I want to it because the car is "exempt" due to being over 10 years old and the speedo already being flipped once or more.... but on the other hand I don't think I wanna go through all that to rip it apart and knowing my luck make it worse, I'll just get a restored one when I take the body off.
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'68 bug (Sadie)

danke meine Freunde

I'm tryin to build a dream one piece at a time, just bear with me.

[whutdidyousay]

but then again, I just might do it..... thanks guys
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'68 bug (Sadie)

danke meine Freunde

I'm tryin to build a dream one piece at a time, just bear with me.

[glutamodo]

As long as you mark the "not original milage" box on the title when you sell the car I don't think there's any problem. There's very few old VW's running around with their original speedometers in them.

-Andy

[whutdidyousay]

I have 9 titles here for my different cars...... they are all blank on the mileage statement..... as long as it's over 10 years it's left blank....... Plus I'm not sure this car will ever get sold
ok, now what's the deal with takin off the needle?..... I might have found a cheap one, and will wanna take it off. If I pull straight off am I gunna screw it up?....
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'68 bug (Sadie)

danke meine Freunde

I'm tryin to build a dream one piece at a time, just bear with me.

[glutamodo]

Really you'd be best to just leave the needle alone - you can do those other tasks while leaving it intact.

But if you really really want to remove it...

What is going to happen is the large coil spring that gives the needle its pre-tension will uncoil a bit and lose the pretension. So you'll have to rotate it around when you go to place the needle back on again. This isn't too hard. The hard part is that the needle fits down on splines, that you won't know exactly which set of splines you had the needle on before. There is no way of marking it for reference before you remove it. So it's a crapshoot, if you don't get it back on in exactly the same spot, the speedometer's accuracy will no longer be correct.

There is one thing you can do though - you'll need a good quality variable speed reversible drill, and a spare speedometer cable. Put the cable in the drill on one end, the other in the speedometer. Then set the drill on reverse and run it at full speed. Note the reading on the speedometer. You might want to do it a couple of times just to be sure your drill is rotating at exactly the same speed each time, and don't put a lot of kinks in the cable either while doing it. Write down that speed, and don't lose it. When you go to put the needle back on, then you'll have a frame of reference "then and there" outside the car as to if you got it back on in the right spot. (The only other alternative is to reassemble it, put it in the car, test drive it, only to find it's reading 45 when you are going 70..... or something like that)

Hope that helps!

-Andy

[Caqfatboy]

glutamodo,

While doing a speedometer overhaul, and trying to reset the odometer I allowed the spring to un-coil, so how many spins of the coil spring would you recommend? I did check the speed with a drill, so I have that point of reference. Is it really a matter of checking and re-checking the speed again and again to simple (moving the needle or where the spline is located to advance or decrease to accuracy) get the same speed for the previous test/check?
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[glutamodo]

The pretension isn't very much at all, it's not much more than is needed to return the needle to the stop position. If you lift the needle over its stop before you remove it you can also tell apporoximately where it needs to be at. However you can break the needle by doing this too.

I just took a junk speedometer apart to refresh my memory on this, and realized I had described resetting the odometer numbers wrong above, so I went and edited it. I'll go and post some pictures here later tonight.

-Andy

[glutamodo]

Okay, here's the pics I took, in answer to a few of the questions above. This is of a late model speedometer that had a bad odometer. Soon you'll see why the odometer was bad.

First of all, here it is before I took it apart, the gas gauge and vibrator are already removed from it:

To remove the bezel that holds the glass face, you have to carefully pry it off. You need to get a tool that fits under there nicely and go around the edge gently prying up every few millimeters. I used the chisel bit on a Victorinox "Swisstool":

After making a couple of circuits prying up around the edge and you should be able to pry the bezel and glass off:

After this, you can remove the two screws (red circles, below) on the back that hold the mechanism to the case, and lift the mechanism out. ( this is a pretty elementary warning, but I'll add that you should do this with the speedometer on its side so the mechansim won't fall out before you are ready.) If it's still there, you may also have to remove the little ground screw for the fuel gauge vibrator (yellow circle) in order to get enough clearance so it will lift out.

And here is the empty speedometer housing. Note it has the rubber holders for the warning light "gels":

Now, here is what the mechanism will look like. If it's an early speedometer the "gels" get glued to the inside of the speedometer face. The Red Arrow I added points to the shaft that you'll have to deal with if you want to change the odometer. If you are lucky you can press this out without having to bend anything. Be careful of where you do this, because if it suddenly pops loose when you are pressing on it, the little gray plastic intermediate gears can slip out of there and scatter. Once you press this out, or bend the retaining tab on one end enough to allow it to be lifted up, you can disengage the intermediate gears. This will allow you to manually spin the odometer numbers. Once you get the odometer wheels to where you want them, you'll have to make sure all the gears are lined up the same way, and then press them back down and pop their center pin back in place.

Now, here is why the odometer was bad on this speedo head. On one side of the speedometer are the plastic gears that are turned by the speedo cable, that run to the center "axle" that supports all of the odomether wheels. This axle is what is turned by these gears, and it is attached to the "tenths" wheel (or the "ones" wheel on older speedos that didn't have tenths), and this gear in turn flips the other gears over, via the plastic gears in that intermediate shaft. When odometers fail, it can sometimes be the long plastic drive gear that's gone bad, but it's more likely a problem with the small gear that presses onto the shaft that turns the center axle. It can simply work loose from the shaft (this is what was wrong on my 85 Golf when I bought it, to fix, I popped it off and "knurled" the end of the shaft with some sharp pliers and pressed the gear back on - it's held since then, over 70K), but it's just as likely for that gear to just crack. (Very common occurance on VW Fox models) That is what turned to be wrong with this speedometer. The red arrow points to the crack, of course:

If you've reset the odometer, you need to verify the gears are going to work OK. In this case I just decided to set it to zero, and since the plastic gear was cracked and loose, I just popped it off and spun that theths wheel with a fingertip for a few minutes to make sure the numbers would turn OK. Went backwards past 99999.9 a ways, the forwards into the 00040's. Worked good with no hangups. If the gears hadn't been right it wouldn't have been able to go back from -0- to 99999 and bacl, it would have locked up. If this had been one with good odometer gears in it, I'd have hooked it up via a cable to a drill and used that to verify the odometer would turn OK.

Okay, now, in answer to how much pretension do you need? Not much on this one. Of course I don't know how well this one was working before either. I thnk it can also depend a little on what speedo you have, as they have different calibration markings depending on the year. But I went and lifted the needle over the the zero post, (and it didn't break) and here is where it ended up with the pretension unloaded - not very far past that post.

And guess what I just noticed, it looks like there is a factory alignment mark right there!! I never knew about that! I wonder if they all have this or if it's just newer ones like this. Hmm, very interesting. However I think I'd still want to do try the "drill thing" beforehand as another point of reference, because I've seen those needles get brittle enough to snap if you were to try to lift them over that zero post.

Okay, the only other thing I'd mention is putting it back together. Make sure you've cleaned up any fingerprints, and wipe off/blow out any dust you can find. Don't try to recrimp the bezel down much before you go to re-install it or it won't go. You'll have to pop it back on there, then put the speedo face down on edge of a countertop and lean on it with one hand so it's seated while you tap that crimped edge gently back down with a small ball peen hammer or something similar, til it's snug again.



ADDENDUM / EDIT

For another series of photos showing even further dismantling, but on a 1964 speedometer, head over to this thread:

http://www.thesamba.com/vw/forum/viewtopic.php?t=327535&

-Andy

[whutdidyousay]

WOW!..... that makes it easy to understand, thanks ALOT, now that I see the pieces I know I don't need to take the needle off.
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'68 bug (Sadie)

danke meine Freunde

I'm tryin to build a dream one piece at a time, just bear with me.

[whutdidyousay]

is that needle on the wrong side of the "zero stop"?
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'68 bug (Sadie)

danke meine Freunde

I'm tryin to build a dream one piece at a time, just bear with me.

[glutamodo]

Yes it is past the stop in that final picture - I did that to show how little amount of preload there is on it past the stop. And it lined up with that little mark on the speedo face, which is why I even noticed it being there. (it might not look quite lined up in the photo, becuase I took the photo at a slight angle to avoid glare from the flash) Since I don't plan on ever using that speedometer I wasn't too worried about snapping the needle off.

-Andy

[whutdidyousay]

thanks alot again, looks like I could paint the needle with it assembled if I needed, that's what I wanted to know, AND I thought you had to dissasemble it from the front.
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'68 bug (Sadie)

danke meine Freunde

I'm tryin to build a dream one piece at a time, just bear with me.

[scottykempf]

heh heh You said vibrator

[glandnut]

Andy- You are a huge asset to this forum, THANKS!!
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Looking for aluminum single port Kadron manifolds.

[Chumley]

Finished mine today, used Andy's tip on the file folder tabs for the cells. Milage was not easy to set, gears have to line up right!

Not too bad for the first one.
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Here I go again

[glutamodo]

looks good!

...and yeah, the gears do have to be in line. Maybe I didn't make the clear enough above, sorry. But that's why I said you'd be best to test the odometer while it's still apart to make sure it flips over properly.
But it is a pain - I remember the first one I messed with, eons ago, and how I lost all the little gears on the floor at one point - aarrgghh!!
-Andy

[Chumley]

yea I set it at all 9's and rolled it over by hand. Thanks for the advice!
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Here I go again