Moderator edit: See post #59 (click here) for additional step-by-step instructions.
I did this job last night. It took about 20 minutes to get the instrument cluster out of the car and would have taken even less had I known I didn't have to unplug everything. All I had to do was unscrew the rheostat, speedometer and tach. I had to remove the tach and rheostat to get the speedometer out of the cluster. Pay attention to how they are arranged. There is a small plate that holds a light in the corner of the cluster that sandwiches in there as well.
The symptoms I have on both my E420's are that the odometer and trip odometer have stopped working. I ordered a gear set on ebay for $40, which came within a few days.
Basically there are three shafts for three plastic gears that usually need to be replaced. There is a small 12-tooth gear and two larger gears. For some reason the other gears involved were fine (I'm sure the people selling the kit knew this). The small gear completely disintegrated, which caused the initial problem. One of the larger gears was also coming apart and missing a tooth.
Replacement of the gears is not difficult. There is a small brass retainer sleeve that holds the small gear on. This sleeve comes off with pliers. [GSXR edit: Do not pull off the sleeve with pliers! Deform it with side-cutters so it slides off the shaft with finger pressure only. Forcing it off with tools will damage the motor.] You DO NOT need the sleeve with the replacement gear. It slides on with enough friction to stay in place. You can access the sleeve and small gear without removing the clear plastic cover. The other two gears require removal of the plastic cover. I removed the sleeve and small gear without first removing the cover because I had only intended on changing the small gear, until I saw that a large gear had a tooth missing too and I determined that all three gears should be replaced.
When you remove the plastic cover, the two shafts with the large gears are actually sticking in the cover, unlike the shaft for the small gear that goes into the unit. Take pictures before you start pulling these gears apart so you know how to get them back together. All the gears slide off the shafts with a little effort.
The two larger gears look the same but are actually different, so make sure you match them up with the existing gears when you replace them.
I was concerned about how far to push the shafts into the gears but it seems that it is engineered such that once the plastic cover is screwed back on, everything falls into place.
I am going to order another kit today and do my 95 E420 this week. It is nice to have the trip odometer back. All in all, it took about an hour to do the job.
I did this job last night. It took about 20 minutes to get the instrument cluster out of the car and would have taken even less had I known I didn't have to unplug everything. All I had to do was unscrew the rheostat, speedometer and tach. I had to remove the tach and rheostat to get the speedometer out of the cluster. Pay attention to how they are arranged. There is a small plate that holds a light in the corner of the cluster that sandwiches in there as well.
The symptoms I have on both my E420's are that the odometer and trip odometer have stopped working. I ordered a gear set on ebay for $40, which came within a few days.
Basically there are three shafts for three plastic gears that usually need to be replaced. There is a small 12-tooth gear and two larger gears. For some reason the other gears involved were fine (I'm sure the people selling the kit knew this). The small gear completely disintegrated, which caused the initial problem. One of the larger gears was also coming apart and missing a tooth.
Replacement of the gears is not difficult. There is a small brass retainer sleeve that holds the small gear on. This sleeve comes off with pliers. [GSXR edit: Do not pull off the sleeve with pliers! Deform it with side-cutters so it slides off the shaft with finger pressure only. Forcing it off with tools will damage the motor.] You DO NOT need the sleeve with the replacement gear. It slides on with enough friction to stay in place. You can access the sleeve and small gear without removing the clear plastic cover. The other two gears require removal of the plastic cover. I removed the sleeve and small gear without first removing the cover because I had only intended on changing the small gear, until I saw that a large gear had a tooth missing too and I determined that all three gears should be replaced.
When you remove the plastic cover, the two shafts with the large gears are actually sticking in the cover, unlike the shaft for the small gear that goes into the unit. Take pictures before you start pulling these gears apart so you know how to get them back together. All the gears slide off the shafts with a little effort.
The two larger gears look the same but are actually different, so make sure you match them up with the existing gears when you replace them.
I was concerned about how far to push the shafts into the gears but it seems that it is engineered such that once the plastic cover is screwed back on, everything falls into place.
I am going to order another kit today and do my 95 E420 this week. It is nice to have the trip odometer back. All in all, it took about an hour to do the job.
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Back cover of unit.jpg111.4 KB · Views: 284
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Remove cover.jpg99.1 KB · Views: 284
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ThreeNewGears.jpg91.8 KB · Views: 303
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ReplaceGears.jpg81.6 KB · Views: 283
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These gears stay.jpg75 KB · Views: 289
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Replace two large gears.jpg79.5 KB · Views: 275
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Large gears are different.jpg65 KB · Views: 278
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Brass sleeve and two large gears.jpg69.3 KB · Views: 301