Odometer not working

Tiny
PETER DAVID
  • MEMBER
  • 1974 BMW 2002
  • 4 CYL
  • 2WD
  • MANUAL
  • 100,000 MILES
The speedo works but the odometer only works now and then?
Thursday, November 25th, 2010 AT 1:50 AM

3 Replies

Tiny
DOCHAGERTY
  • MECHANIC
  • 9,601 POSTS
The drive for the odometer is a cable from the transmission and it may require some expertise in the realm of German instrumentation to have the Speedo and Odo work as a unit instead of intermittently. The Odometer is geared off the Speedometer and there may be something gummed up or? Carl has seen it all, he will know.
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Thursday, November 25th, 2010 AT 5:48 PM
Tiny
THE DUKE
  • MEMBER
  • 1 POST
If your speedo still works, but the odometer has stopped paying attention, you have the classic 2002 odometer failure. You can take it to a speedo shop and pay $75-150 for a repair, or pick up a used instrument cluster at a swap meet or salvage yard for less than half that. Chances are, if you are skilled with tools and patient, you can fix it yourself for free.

Repair Instructions:

Here is a lollipop stick being used to drive out number wheel shaft.
Please note: I had previously advised fixing gear to the shaft with super glue, but that repair doesn't last nearly as long as the distortion method above.
Curt Ingraham
72 tii
Oakland

1. Remove instrument cluster from dash.
2. While speedo is still in cluster, loosen big nut on back of speedo.
3. Remove speedo from cluster. Handle carefully. Resist temptation and do not touch needle or face.
4. Remove big nut and washer from back of speedo.
5. Remove speedo from back plate.
Notice that:

a) Speedo cable input on rear drives speedo;

Shaft from speedo to odo drives odo number wheel shaft;

c) Odo shaft drives a big aluminum-colored gear at the end of the odo number wheel stack;

d) Odo is not turning because that big gear is slipping on the number wheel shaft;

e) Number wheel shaft is held in position by friction with big gear.
6. Gently slide the number wheel shaft back and forth a very small amount to verify that it is loose.
7. Find a temporary replacement shaft of slightly smaller diameter, such as a nail or machine screw.
8. Replace number wheel shaft with temporary shaft as follows:

a. Identify end of number wheel shaft withOUT the gear.

B. Place end of temporary shaft against end of number wheel shaft.

C. Slowly and carefully press temporary shaft in, forcing numberwheel shaft out.

D. At this point, temporary shaft is in, numberwheel shaft is out, and numberwheels are still in place.
9. Locate position on numberwheel shaft where big aluminum-colored gear normally sits. A polished band likely exists there. Verify gear location by holding shaft against numberwheel frame.
10. With a center punch or cold chisel make a very light impression on shaft at gear location. This distortion should be large enough to fit tightly in gear, but small enough to pass through numberwheels using finger pressure.
11. Try replacing numberwheel shaft in odo frame. Keep numberwheel shaft end against temporary shaft end.

A. If numberwheel shaft won't go through odo frame or is tight in numberwheels, distortion is too large. File slightly.

B. If numberwheel shaft slides all the way in easily, distortion is too small. Punch it again.

C. When distortion is just right, shaft will stop sliding when distortion reaches gear, and will not go into gear with finger pressure.

D. Use channel-lock pliers or a small vise to press shaft firmly into position in big gear. Leave a very small gap between odo frame and small brass gear at other end of shaft.
12. Verify that numbers on numberwheels align correctly with rectangular hole in speedo face.
13. Remove shaft between speedo and odo by removing one screw. Turn numberwheel shaft with fingers and verify that wheels turn smoothly, and ten's digit advances when one's digit goes from 9 to 0. Replace speedo-to-odo shaft.
14. Replace back plate, washer, and nut (finger tight) on back of speedo.
15. Clean speedo face with careful puffs of canned air. (If more cleaning is needed, use water and lens tissue.)
16. Replace speedo in cluster, engaging trip odo reset shaft.
17. Reassemble cluster.
18. Tighten big nut on back of speedo, noting alignment of speedo face.
19. Reinstall cluster in dash.
20. Test speedo and odo.
21. Reinstall underdash panels.

Hattip: Curt Ingraham
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Saturday, March 2nd, 2019 AT 8:53 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,904 POSTS
Excellent addition to this thread! Please feel free to help out whenever you are on the site :)
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Tuesday, March 5th, 2019 AT 11:21 AM

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