Audi Type 85 (4K, 4KQ, Coupe GT) Odometer Repair Procedure (long)

[Tony Lum]

Introduction

Tired of having a non-working odometer and trip meter?  Constantly 
disassembling the instrument cluster to push the odometer axle shaft back into 
position?  Trying to attach a gimmick to keep the shaft in position?  Here’s 
what I think is the final fix for the problem.  First of all, the small 15 
tooth nylon gear that drives the axle shaft must not be split.  Find a 
replacement in the junkyard or glue it together.  Sometimes this is all you 
need to fix the odo.  If the axle shaft is coming out of the housing and losing 
contact with the spiral drive gear then you’ll need to perform the following 
steps.  It’ll take about a hour or more depending on your patience.

Tools needed

Jeweler’s screwdrivers, 7/32 nut driver or socket, needle nose pliers, Wiha 
#26810 Chip Lifter (http://www.wihatools.com/268serie.htm), tweezers (I used a 
Selecta 24-SA).
The chip lifter is very handy for removing the speedometer needle and pushing 
on the right side of the odo axle shaft underneath the O2 sensor mileage switch 
counter.

Procedure

Once you’ve removed the instrument cluster from the car, set it face down on a 
table and remove the 8 Phillips head screws that secure the white plastic back 
of the IC to the housing.  Also remove the 4 screws (7/32”) holding the 
speedometer to the white plastic base.  If you have the trip computer version 
remove the cruise control wiring and disconnect the red wire attached to the 
temp gauge.  Carefully lift up the entire white plastic base and turn it face 
up.  Unplug the red and brown wires attached to the posts on the base.  Now 
lift out the speedometer assembly.  Next lift the speedometer needle over the 
stop post and note its rest point.  On mine, it lines up with a white tick mark 
on the edge of the speedo’s face plate.  Use the chip lifter tool to remove the 
needle by applying pressure on end of the needle’s shaft.  Do NOT try to lift 
off the needle by pulling on the cap with your fingers!  The needle’s on pretty 
tight and I’ve broken several by trying that tactic.  Now remove the 2 screws 
holding the face plate to the speedo and lift off the plate.  Now you can see 
the guts of the speedo.  See the pot metal gear on the right side of the 
odometer counter?  This gear drives both the trip meter and the odometer and is 
the source of the problem.  If your nylon gear that drives the axle shaft is in 
good condition, pry it off by holding the brass spacer behind.  BTW I always 
thought that this spacer was a bearing that the odo’s axle shaft passed thru. 
Turns out that the spacer is pressed fit onto the shaft and is very firmly 
attached to it.  Now carefully slide the axle shaft out of the odometer 
housing.  Pull slowly, all six digit wheels will be let loose.  Now pull the 
pot metal gear out with the tweezers.  Insert the axle shaft back into the pot 
metal gear.  See how the axle shaft spins easily in the gear?  That’s the 
reason the shaft backs out of the speedo housing.  This gear must be rigidly 
attached to the axle or the odo and trip meter won’t work correctly.  After 
150K or so miles, the pot metal wears out allowing the shaft to come free.  I 
first thought of using glue to hold the gear to the axle shaft, but there is no 
way to apply it in the confined space.  So I took my needle nose pliers and 
squeezed the flange on the gear where the axle passes thru. You’ll want it 
tight enough that it takes a fairly high effort to pull the shaft back out of 
the gear.  Once you’re satisfied with the axle’s fit in the gear, slide the 
axle back into the speedo housing and thru the six digit wheels.  Place the pot 
metal gear at the end with the teeth facing the right side of the speedo.  Make 
absolutely sure the digits are at the very apex of circle as seen from the 
side.  Wiggle them to be sure, because if they are misaligned, they’ll stay 
misaligned.  I had to remove the axle shaft several times to get it right. 
Press the axle thru the pot metal gear-it should take some effort.  Now check 
the odometer by rotating the last digit on the trip meter.  The gear should 
turn easily and the digits on the odometer should fit loosely on the shaft.  If 
not, press ever so slightly on the right end of the shaft with the chip lifter 
tool or what have you until you have that fit.  If its binding at all you’ll 
just increase the wear in pot metal gear.  Now reassemble the speedo and IC and 
go out and take a drive and enjoy your working speedometer.

Happy driving,

Tony
’83 urquattro #302
’85 4kq