Odometer Fix/Cluster upgrade

[vannymcvan]

Was going to make a metal clamp stop for my odometer and then stumbled on this: https://uniwerksdesign.com/product/vanagon-odometer-worm-gear-clamp/

By far the cleanest & best option I've seen...

[deaddrift]

Welp, my odo stopped working on my recent trip to SE Oregon, so I found this thread and took the thing apart. Butcher's thinking on fixing the gears to the shaft to prevent the axis slipping sideways seems best, but sadly I didn't read that until I'd already installed a stop piece like other posters.

However my REAL problem is that the instrument housing has cracked and fallen into pieces on two of the odo assembly mounting screws. SO, I plastic epoxy'ed it together--I'm certain a new instrument cluster housing would be $$$$$ if it were findable at all.

Many thanks to all concerned for the extremely useful info!

EDIT: Well it turned out I am not a very good reader. Here's a summary of what I know now:

1. The two spoons trick for removing the speedo needle is perfect.

2. When everything is in position, NONE of the gears or digits on ANY of the odo axles should turn freely. They are all driven by the worm gear. If something spins by hand it's out of order.

3. If the axle drifts sideways, then it's because a gear has come loose and needs to be re-secured. I no longer think that the end cap solution will actually solve the problem, long term. For me, it just kept the axle in place while the metal gear spun fruitlessly on its axle.

4. Nicking or peening the axle to re-secure the metal gear should be done VERY(!) GENTLY. I couldn't believe how much I had to polish those nicks so I could get the axle back in! I finally made a receiver for the end of the axle out of some stacked washers, which allowed me to use a drift and hammer to knock the axle back into place through the gear. I was worried I'd crack the plastic of the axle housing without the washers to bang against.

4. Keeping the gears lined up is tough. A finishing nail worked well for me.
_________________
Nat

'91 syncro Westfalia, 2nd and 4th owner

Ò,ó

[SyncroHead]

Vanagon odometers fail pretty regularly when they get to be 25+ years old. I’ve had mine apart to repair in my ’87 Syncro and my ’89 Westy to repair myself, and I’ve also sent mine to a repair service.

In this post I hope to describe the drive mechanism in a late model Vanagon odometers, summarize common failure modes, and also summarize some of the repair methods. Hopefully illustrating with a few photos including embedded notes will make this more clear to an odometer novice.
Since removing the cluster from the van and removing the speedometer from the cluster are pretty straightforward, I won’t touch on that. Also, removing the needle and faceplate are pretty well covered, so I won’t reiterate that except to say, be VERY careful with the needle – it’s very fragile!

DRIVE MOTION AND COMMON FAILURES

If you’re diagnosing an odometer issue, it’s important to understand the “flow” of motion (or “drive”) in the odometer. I’ll describe that below as well as describe a couple of common failures and fixes.

Speedo cable goes into the black housing and induces the needle to move. This post is not really about the speedometer needle, so I’ll leave it at that and focus on the odometer.

The drive comes back out of the speedo housing to drive the odometer with the white plastic worm gear.

The worm gear drives the small white plastic gear that is “permanently” pressed onto the shaft.

The white plastic gear drives the shaft. Here’s one very common failure spot: If the white plastic gear cracks, it loses grip to the shaft and when the gear spins, the shaft does not.

The shaft goes through all the number wheels, NOT engaging them, but only acting to align them and they can spin freely on the shaft. The number wheels are NOT turned by the shaft. (They don’t actually spin because they are held in lock-step by the other number wheels. More on that later.)

The shaft drives the metal gear at the other end which is also permanently pressed onto the shaft. This means the white plastic gear, the shaft, and the metal gear all act as one unit. If one gear moves, the shaft moves the same. If the shaft moves, both gears move.

Here is the second common failure spot, when the metal gear loses grip on the shaft. This means the shaft can spin without turning the gear. This gear’s left/right position on the shaft keeps all the shaft and all the number wheels tightly together side-by-side. If the metal gear loses its shaft grip, not only might the shaft spin without driving the metal gear, but this also allows the shaft and plastic gear to slide away from the metal gear and even lose its connection with the clear plastic carrier housing.

Keeping the shaft from sliding out sometimes helps, if the shaft somehow still has enough grip to the metal gear to drive it, but this is not likely. Holding the shaft in place is just a band-aid when the real issue is the metal gear’s grip to the shaft. There are even 3-D printed parts one can buy to keep the shaft from slipping out of the carrier.

An example of a home-made shaft retention device.

So far the drive has gone left-to-right through the center of the number wheels with the plastic gear driving the shaft, which drives the metal gear.

Now, the drive starts moving right-to-left as the metal gear drives the 1-mile number wheel with the gears on the number wheel’s right side. The metal gear has a pair of gear nubs on its left side. These engage the 1-mile wheel each time the metal gear makes a full revolution and increment the metal gear one position.

Likewise, on the left side of the 1-mile number wheel is one pair of gear nubs by the 6/7 numbers. Once the number wheel makes one full rotation, these nubs engage the 10-mile wheel and increment it 1 position. This continues across the number wheels right-to-left, each wheel subsequently turning the wheel to its left, until eventually reaching the 100,000-mile wheel.

FIXES

White Plastic Gear:
If the white plastic gear loses grip to the shaft, it can sometimes be repaired with super-glue (CA), but often this fails because there is residual oil from the mechanism that’s gotten between the gear and the shaft or in the crack. If you attempt this repair with glue, make certain no traces of oil are left at the white plastic gear.

Metal Gear:
The press-fit of the metal gear on the shaft sometimes fails, but without any crack like afflicts the white plastic. Making the gear grip the shaft again means the gear needs to be removed from the shaft. Sometimes the entire shaft is removed. If you remove the shaft, do it by pushing the shaft out with a similar diameter wire or drill bit. This causes the drill bit to replace the shaft and keep the number wheels aligned.

Knurling the Shaft: This method focuses on creating ridges on the shaft that engage with the metal gear. This has been done with firm pinches from “lineman’s pliers” or other pliers that have prominent gripping surfaces between the jaws. The intent is to crimp certain portions of the shaft’s surface causing adjacent areas to swell out a bit. I used this method by using the edge or a file and hammering it against the shaft to create the knurling. This is pretty sensitive though, because if it’s dome too much, the shaft won’t even fit back through the number wheels. This was my fate and I filed off the knurling and moved my attention to the gear. Other knurling or splining methods might be used to cause the shaft to re-grip the gear. Here’s a photo that looks like scratches were made along the shaft with a sharp tool.

Dimpling the Metal Gear: This method is used to make the hole through the metal gear deformed and slightly smaller, so when it’s replaced onto the shaft, it will grip. This is done with a No. 2 Phillips screwdriver and hammer. (Yes, repairing a speedometer with a hammer does sound strange!) Lay the gear on a flat solid surface, place the screwdriver’s tip into the hole as though you were going to push the screwdriver through the hole. Of course you won’t because the screwdriver is way too large. Now hit the handle end of the screwdriver with a hammer causing the four splines of the screwdriver to deform the hole and “dimple” it. Turn the gear over and do the other side. How hard do you hit it? That’s tough to describe, but probably harder than you think. My first “repair” using this method lasted only about 1,000 miles and the metal gear came loose again. The second time is still working, but has not yet even reached 100 miles.

MILEAGE ADJUSTMENT
While the metal gear is out of the assembly, the side-by-side “tightness” of all the number wheels is lost and they are loose enough to spin each one independently on the shaft. Now is the time to reset the odometer to what you estimate to be the accurate mileage on the van. Last time mine stopped, I kept pretty accurate notes on all the trips while the odometer was stopped, so I think mine is now again within just a few miles of what it should read.

REASSEMBLY
Above, I described how each number wheel increments the wheel to the left one position for its own full rotation. A little more info on that is useful now. The incrementing is done by engaging a very small gear that rides on a different shaft above the number wheels. It actually does this in two steps, one for each of its gear nubs. The first nub moves the next wheel 1/2 of a position and the second nub does likewise to make one full increment. I bring this up because when reassembling its possible to set the number wheels halfway between one position and the next. If this happens, your 1-mile wheel will rest hallway between 2 and 3 for a mile, then move to halfway between 3 and 4 for the next mile and so forth. This means when you realign the number wheels and re-install the metal gear you must make certain every wheel is in a full-digit position or it will continue forever (or until it breaks again) to display the bottom half of one number and the top half of the next. Quite irritating – at least to me.

You can now slide the shaft back through the number wheels smoothly, pushing out the drill bit that’s been the placeholder. The shaft should not be difficult to press through the number wheels. Once the shaft has reached the metal gear, you will need to press the shaft back through the metal gear so that it won’t spin, it takes some force to push it through. If it doesn’t require more force than you think it should, it’s probably not tight enough. Don’t press the shaft back through the metal gear until you’re completely satisfied that the number wheels read properly and are aligned. You might want to lay your faceplate over the top so that you can accurately see what will show through once reassembled. If you get it wrong, you’ll need to pry it apart instead of just finding that it fell apart!

The best way is to jig-up a press something like this so you can supply smooth, even pressure to push the shaft back through the gear.

This is not my press, I don’t have one.
I resorted to using a hammer again, but did it very carefully applying smooth even, ummm... blows.

You’re finished installing the shaft when the white plastic gear lines up with the center of the worm gear and the other end extends past the metal gear and fully rests in the clear plastic carrier. Might even protrude a smidgen.

Thank you David Beierl and a couple others whose photos I used to illustrate this post. Annotations on photos (and any mistakes in them) are mine.

Hope this is useful!

Jim Davis
_________________
"A Vanagon? It's not a car or a van. It's a hobby!"

Check out:
www.VANAVATION.com
www.SyncroSafari.org and
www.Vanagons.org

[Butcher]

Great write up.

[SyncroHead]

[dbeierl]

[LandSailor]

Just to confirm...

There is no metal bushing in the plastic on the right hand side for the main odometer like there is for the trip odometer.

Correct?

...so I didn't drop anything?

[ALIKA T3]

[truepaul]

I applaud you for this excellent write-up!

I successfully repaired the odometer on my previous van (a 1982 Vanagon Westy) 2-1/2 years ago. I made all the newby mistakes, and bad hammering technique resulted in a smashed worm gear (unrepairable) and later a smashed white plastic gear (same). Oh, and a *slightly* bent shaft that never worked again, after I tried to "peen" the darn thing (see write up on other Samba posts). Thus before I was done, I purchased two or three broken speedometers to scavage for parts.

I want to let everyone know you can get a replacement for the white plastic gear !

[mrloginname]

Just completed this fix myself, and echo the appreciation for the excellent write up and associated advice. I have been dreading the process for years, but after reading this thread it really wasn't that difficult. Just take your time and you'll be fine.

One thing to note: it looks to me that the worm gear "pulls" on the shaft as it rotates, which IMHO is a big part of why the shaft pulls out of the metal gear on the opposite end. I scored the metal gear using a screwdriver, per everyone's instructions, but ALSO added the clip from Uniwerks Design (mentioned up thread). My thinking is that the clip will reduce the gear's ability to pull things apart, since it limits how much the shaft can travel. Cheap insurance, in other words, and buying one of the clips supports a small business that supports us.

Just my .02.

Also, I marked the metal gear and the housing with a sharpie before I pulled everything apart so that I would be sure the gear would end up back where it belonged. Just a suggestion for making sure everything goes back the way the VDO gods intended.

Anyway, odometer is now functioning as it should. Thanks, folks!

[doodledee]

Hey all -

Here's one I haven't been able to figure out and also I think I probably just broke something. Classic move.

Was fixing the odometer - metal gear was slipping, so carefully pulled out metal rod and added some VERY SMALL imperfections to it (truly very small is all that's needed) and then re-assembled. Had to use a bit more thwacking to get it back together than i expected but it works great now.

After re-assembly, the odo works great but now the speedo is dead. I believe the pin the needle mounts on is somehow broken, as it pulls freely out of the rear cable assembly (though still attached to the spring). This would mean that as the cable spins, it's not actually turning the pin that the needle itself is connected to. No pin spin no speedo.

Is this fix even possible? Are parts available? I haven't found this problem anywhere on the forums. Fallback would prob be a new GPS based speedo, which i suppose is ok but also love keeping the old stuff alive.

Picture below. THANKS FOR INFO!!!

[ddevriese]

anyone know the dimensions of the white plastic gear. I see the post below where i can buy for $25 but if it is a common size i can 3d print or buy cheaper

[ALIKA T3]

[mrcool]

Bringing this back from the dead. as well as my account..
I also have the issue of the white round gear not staying in place. I've seen several fixes on here and before I try it I want to see if anyone else has info on what the gear should look like... The shaft does not spin on the gray gear so I dont think scuffing up the shaft is the right answer at all.

I've removed the shaft and I am curious if the white gear should be flush with the brass(?) segment on the shaft.

There are replacement gears but I rather not try forcing the white gear flush. https://www.odometergears.com/products/Volkswagen/Mechanical+Speedometer/19

[/url]

[ALIKA T3]

If you look at other pictures, it's not flush with the brass ring.
It's flush with the tip, maybe slightly deeper , a smidgeon bc the tip is chamfered.
_________________
Silicone Steering Boots and 930 Cv boots for sale in the classifieds.
Syncro transmission upgrade parts in the Classifieds.
Subaru EJ22+UN1 5 speed transmission
http://www.thesamba.com/vw/forum/viewtopic.php?t=416343
Syncro http://www.thesamba.com/vw/forum/viewtopic.php?t=4...num+gadget

[mrcool]

Is that how its supposed to be, or part of the reason we are all posting pictures of bad ones?

[ALIKA T3]

[mrcool]

[mrcool]

Update: the white gear does sit flush with the brass bushing. I pushed it back into place but 4/10ths of a mile later the gear was pushed back out. And this time it came out further. So if your odometer looks like your "1's" digit is about to fall back into the cluster that might be your issue.

I would think this is happening because the white gears need to be lubed up as well. If there isn't too much force on the white gears it wouldnt be pulling out of the lead gear.


I am ordering a new grey (lead) gear from odometer gears that once installed will not spin. I'm not excited about marring the shaft so the gear won't spin.


FYI:
When people say your shaft shouldnt spin, that means if you hold the little white gear still and then on the other side try and spin the lead/grey gear with a screw driver it should not budge. That was not clear to me in the first post

[DuncanS]

My white gears/number wheels were stuck because of corrosion on the shaft. If you lube them, watch oil only. But without removing them and cleaning the shaft then you will have to redo it again quite soon even if it works. And it may not as the gear/wheels must have zero resistance on the shaft.

Duncan