Speedometer reset

[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

[olde skool]

Thanks glutamodo, with your advice I reset my '68 speedometer back to zero miles and replaced the gels looks awesome!!!

[wcfvw69]

Your the man Andy!

My needle was bouncing at lower speed. I lubed the speedo cable (which appeared to be ok). I then took the speedo apart and found the grease under the magnet and drive assy to be pretty old and thick! The magnet didn't spin very easily. I sprayed out all the old grease with carb cleaner, relubed it up and it spins very easily now.
I reinstalled the speedo after setting the mileage to what my new engine has on it and no more bounce!

Great pictures Andy and you DO ADD LOTS of value to this site.

Good job!
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40+ years of VW repair, and VW parts and vehicle restoration experience.
The Samba member since 2004.

**Now rebuilding throttle bodies for VW's and Porsche's**
**Restored German Bosch distributors for sale or I can restore yours**
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[orbitron]

My speedo is intermittant. The odometer seems to work fine, but in just sub-zero temps, it wails like nobody's business and then quits indicating entirely. Initially I thought it was the speedo cable but the odometer still works so it must be inside.

any insight?

I'm trying to decide if I should fix the old one or convert to metric...
http://www.cip1.ca/ProductDetails.asp?ProductCode=VWC%2D113%2D957%2D055%2DD

[wcfvw69]

Take it apart and see if you had the same problem as me. Sray some WD40 in the speedometer cable to free it up and relube the gears inside. Mine works like new know.
Its not a hard project, just take your time.
_________________
Contact me at [email protected]
Follow me on instagram @sparxwerksllc

40+ years of VW repair, and VW parts and vehicle restoration experience.
The Samba member since 2004.

**Now rebuilding throttle bodies for VW's and Porsche's**
**Restored German Bosch distributors for sale or I can restore yours**
**Restored German Pierburg fuel pumps for sale or I can restore yours**
**Restored Porsche fuel pumps or I can restore yours**
**Restored Porsche distributors or I can restore yours**

[orbitron]

Bought a used metric one on Friday. I'm not sure if I'll gut it or not though. Not sure about the Canadian laws when it comes to resetting speedo's though

[jkyes]

just got mine apart this am, and i have a cracked gear just like the one in the pict. speedo works, odometer turns by hand, it appears to just be the bad gear, is there a fix? are there replacement parts?
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[glutamodo]

Try contacting these guys for the gear:

http://www.speedometerplus.com/

[Fowvay]

My 70 came with a 100mph late model Speedo so I bought a well used and dirty 3/70 speedo out of the classifieds.

Thanks for this post! I got it all cleaned up but I didn't bother to roll back the miles since the miles fit the look of my bug nicely.

I also found it very easy to calibrate the preload using the factory alignment notch. Just be gentle lifting the needle up and over. For the gears I used a moly blend water proof marine grease meant for lubing up gauge shafts on ships. I keep it around for lubing cables etc. Worked the charm. The needle is super smooth and no jumps.

before:

During:

After:

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[mnussbau]

[jmsmilin]

looking to rebuild a speedo-where does one get needle-chrome ring-gels-lens etc?
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