Unofficialbmw.com

[Billo]

Does anyone have pictures of the odometer gear that seems to be bad about stripping? What is the actual size of the gear (ID OD). How many teeth? My odometer stopped working and from what I have read, that seems to be a common problem. I may have a solution for that problem that would be easier than having to order and wait. I won’t be able to tear into that project for a few more days and I would like to see what I’m up against. If it works, I will be glad to photo my project and share the solution.
Thanks!
Bill

[ 07-01-2003: Message edited by: Billo ]

[ExemptX2000]

I would snap a few shots of mine, but there was nothing left to it...

[Billo]

I wonder if the gears everyone’s talkin’ about look like this. Well, what do ya think? I have read several posts where the gears have just ‘vaporized.’ Any responses welcome. Thanks; I’m determined to fix this.
Bill


[ 07-01-2003: Message edited by: Billo ]

[metonymy3]

Does this gear stripping affect both the regular and trip odometer, or just on or the other? Both of mine have quit working.

I'll be watching this thread too. Thanks for any help.

Chris Tullis

[dunnavant]

That "E1" gear is usually the one that crumbles and yes it drives both trip and regular odo. Sometimes the "E2" (the first driven gear) will also have a few missing teeth (one tooth missing, on this one, is no problem by the way). From past experiences DO NOT try to reuse an old drive gear! They do not like to be disturbed. Even if the rascal is intact, it will not be for long if you move it to another unit. Super glue may work for awhile but this is iffy as well... $25 for that little gear is worth it vs. playing around with salvage gauges. I install with the flange in but it will work either way.

[haber]

I've been through the E1 gear replacement and posted this method sometime back. I know it worked for two of us because I shared my spare gear. Someone needs to order a batch of these gears and share them around the board. I wish I had but that was before i really found a home here. Anyway, here it goes if your cheap like me and want to do the $3 fix.

From old post...

Here was my method of odometer repair. I hope it will prove useful to others and I wish now I had taken a picture to share as well. If someone can pass on to the webmaster as Charlie suggested, I’m not sure how.

After my speed/odometer was out of the instrument cluster it was obvious that the drive spur from the odometer motor was kaput. It is a small plastic drive gear on a brass hub that is pressed onto a shaft that crossed over from the odometer motor to the drive gear side of the mechanism. It appeared to me that BMW/VDO just picked the wrong plastic and durability is poor. Maybe they have recognized and fixed this on later models.

Remove the screws and cover to the reduction gear set on the drive side of the odometer. Slide out the reduction gears to avoid damaging them an inspect them. Mine, thankfully, were in very good condition. Make sure you get any pieces (teeth) from the drive spur out of works or they will bind it back up. I then cut the plastic inner portion that remained on the drive spur since primarily the teeth had stripped off. It was quite soft and no trouble to remove. The old gear had a knurled brass hub that measured about 3.4mm or .134" in diameter if I remember correctly. A caliper or micrometer to check this would be a good idea to guide you in the next steps.

At this point you might also check the working of the instrument. If you put the reduction gears back they should spin very easily and roll off some miles. If you put it back into the dash with the lens off you can feel the drive spur hub flip over now and then to verify the motor is good. (you need to be moving which is not such a good idea to recommend though) I did this and also drove around a few days with no instrument cluster or warning lights while waiting for the part I ordered. It's weird driving without them but the car runs fine with everything out.

I purchased a new gear from Sterling Instrument (www.sdp-si.com), part number 'A 1B 1MY05012'. This is a metric module 0.5, 12 tooth hubless pinion. There are no inch size gears that will substitute. This new gear has a 3mm bore or .118" and a 4mm face width and is made of brass. The gear is only about $3 but be prepared to pay a small order charge plus S&H. I bought 2 just in case and now wish I had bought more to share with others.

My approach was to bore this gear out and press it onto the remains of the old spur. There are metric drills available in increments of 0.1mm and there are number size drills that get close. I used a number 30 drill which brought the bore out to .1285". A number 29 is too big at .136" and a more commonly available 9/64" drill (.141") was much too big. Alternately you might be able to start with an 1/8"(.125") drill but then the next step will be more difficult. I was lucky to have a good model shop here were I work and can borrow odd items like this.

The next step was to hone the gear out until it was just undersized. This takes a little finesse but not too difficult. I used a Dremel tool with a 1/8" carbide bit to slowly hone the gear out until it was just slightly under. I put the Dremel tool in the bore and rolled the gear as light pressure was applied. Don't get in a hurry or you could overshoot your target. Periodically check to see when the gear is just starting to push on to the old spur hub being careful not to get it so big it slides right on. You might want to try to taper one side just slightly to get some lead in.

Remove the screws and plastic cover on the odometer drive motor (opposite side) and also remove the magnetic rotor and small ball bearing on the end of the shaft. Support the end of the shaft on something softer than the metal shaft like a block of wood or plastic and gently tap the spur gear onto the original brass hub. If it is not going on with a light force then it needs to be honed out a bit more. I used a 1/2" x 6" socket extension to tap it on with little more than the weight of the tool applying the force. I suppose LocTite, epoxy or the right glue would work if you get it too loose but I was afraid of getting that in the wrong places like gear teeth. A good press fit is best I think.

Re-assemble everything making sure the new drive spur is lined up with the first reduction gear. There was plenty of lube on the old gears to transfer to the new spur. Spin it for a few 'miles' forward and back to make sure everything is working. It should take very little force and if you meet any resistance then something else is jammed up. Now if your trouble was just like mine you’re good as new.

Mine has been good for a couple thousand miles or about an oil change now.

Actually it has been months and months and a few oil changes. Still working like new.

Good Luck if you give it a try.

[Houstonguy]

I like haber's method especially because it uses a brass gear instead of the flimsy plastic gear VDO decided to use. Unfortunately, he is correct about the pricing. Once you get hit with the small order charge plus S&H, you're up to about $30 for a gear! Also, if you don't have any way to drill a concentric hole, it might give you some problems.

I am working with a company right now to get them to make me some of those gears in brass as well. They may be able to get it done for well under $10. If so, I will let you guys know and have them available to you guys at cost; hopefully around $5. We'll see once I get my cluster apart again for them to duplicate the gears.

[Billo]

I can’t tell you guys how much I enjoy this board. I thought I was the only one that did stuff like that. I’m amazed! Some folks think it’s foolish not to run down to the dealer and buy whatever’s necessary. Well, “necessity is the mother of invention.” It seems a waste to me not to use those little talents we have. Thank you haber for the post.
Bill

[ 07-01-2003: Message edited by: Billo ]

[haber]

Billo, your welcome. If I had only known at the time this was such a common problem and this gear would work, I would have ordered more. I should have got about 20 to get over the small order charge and would have passed em out for free to the board.

Houston, Stock Drive Products was also selling pinion wire in that metric gear. It was a much longer length of the brass material with the gear profile. If you know someone with a screw machine they could knock out a bundle of these gears in no time at all. You might check it out. Billo will probably be your first customer!

[metonymy3]

If anyone buys a bunch of gears, I'll get in on it! Houstonguy, when do you think you might have those gears ready to buy?

Chris

[Houstonguy]

Haber is a good man, better man than me. I wish I could afford to get it for everyone for free, but I cannot. I think I'm the young guy in this group, so my funds are limited. I will of course try to get it done as cheap as possible. I have access to the Texas A&M machine shop, FREE. I will look into getting that pinion gear and having the machine shop process it.

I want to make it 'plug and play' for you guys. I want to make sure the hole is a perfect friction fit so you guys don't have to dremel it out yourself.

When? It all depends how soon I can get the pinion gear and when I get out to the A&M main campus. I hope you guys can hold out for another couple of weeks. It will be free to you guys if I can bribe the machine shop guys to do it for a couple of beers.

I'll keep you updated.

[Houstonguy]

Forgot to mention, I'm also trying to get the reduction gears made in brass. If only the E1 gear is brass, it is only a matter of time before it eats away the soft reduction gears due to vastly different material properties of brass vs. thermoplastic.

While you're in there replacing E1, why not do them all? If anyone has the specs for these gears right off hand, I'd appreciate the input. Thanks.

[metonymy3]

I took apart my cluster, and found that the small 12 tooth gear on the odometer as well as the first two reduction gears are fried. I found http://members.ispwest.com/jkcaplan/gearwebpage/gear.html, where they have the E1, E2, and E3 gears in plastic (at $25 each!!). The problem is that I have a Motometer cluster, not the VDO. Does this completely hang me out to dry for odometer gear repairs? I got to counting, and my first reduction gear has 44 teeth, and the one pictured has 50 or more. I'm thinking that one's not going to work. What do I do?

Chris