Odometer gears

[Theotherotter]

My ‘78 530i has a non-functioning odometer - no surprise with an old VDO odometer. Tonight I was disassembling the speedometer on my 911 to repair an odometer that just quit - it’s the usual gear - and I ordered the replacement from odometergears.com. If I get to fixing the intermittently operating odometer on my Saab before I’ll sell it, I’ll do the same. However, they do not have a listing for E12s. Closest BMW by era is the E23. Where can I get replacement odometer gears for an E12, or what other model might they cross-reference to? (E28s?)

[Mike W.]

Jeff and ODO gears does have gears for E12s, you just have to figure out which one. It's the first one under BMW, Mechanical Speedometer. https://www.odometergears.com/products/ ... edometer/9

[Theotherotter]

Thanks! I would not have figured that out on my own. are the tooth count for the odometer gear and thickness for the lead gear for my car (US 530) known or am I going to have to take the cluster out and count/measure first? For the 911 it's easy, as all 76-89 US are the same. For my Saab, you have to look.

[Mike W.]

I think you're going to have to look. At least I don't know the number. Unless you think or know it's a problem, I wouldn't bother with the lead gear. Actually I think it's zinc, not lead, but he shows lead. The plastic one is typically the one that fails, either by splitting in half, sometimes losing a tooth in the process, or just by slipping on the shaft.

I've been known to repair them by lightly scoring the shaft with a wire cutters, lightly, nominally lenghtwise with the shaft, a tiny dab of superglue and a collar of 1/16" welding rod on both sides to prevent it from resplitting. But I started doing that back in the early 90s long before the internet and Odo gears.com.

[Theotherotter]

I'm also assuming it's the plastic gear, as that's what it nearly always seems to be. The Saab I'm less sure of, as the odometer does work sometimes. It always gets hung up eventually when the trip odo hits xxx.9

[Robert Bondi]

Ditto on Mike's input. Jeff Caplan at OdometerGears is the way to go and he's also an E12 guy. He helped me fix the odometer on my Euro restoration car about 5 years ago. You should pull the unit to know exactly the tooth count. I think there are many gear variations and it's usually obvious by either the split or loose tooth which gear you need.

Jeff even walked me through part of the process on a Skype call with my phone...using the phone camera for real time looks. Putting the needle back on the speedometer was very unsettling, but he has a method to do it and it works.

[Mike W.]

Putting the needle back on the speedometer was very unsettling, but he has a method to do it and it works.

Putting the needle back on? I've never pulled it off do fix odo gears. I have removed the screws that hold the face on to loosen it up and get more working room, but never pulled the needle off.

[Theotherotter]

I am in the middle of this process on my 911’s speedometer - getting the trim ring off is the biggest PITA of the process but taking the needle off without breaking the shaft can be a little nerve-wracking. I got it off easily. I’ll get to the E12 eventually, maybe this summer. I don’t think taking the cluster out is too hard from what I recall seeing.

[Robert Bondi]

Putting the needle back on? I've never pulled it off do fix odo gears. I have removed the screws that hold the face on to loosen it up and get more working room, but never pulled the needle off.

Yeah, this was about 5 years back in the heard of COVID. My repair either required removing the needle or Jeff just thought it was so straight-forward to do it that way....It certainly felt like a one-way ticket removing the needle, but he was quite confident and it worked out.