[AlanPerry]

I posted about flat-towing my smart and the code thrown last week. I got the car back on Friday and just disassembled the clutch actuator to get to the bottom of the failure.

The work was done at a European car repair shop a short walk from my house (that and I had had the shop work on my Golf was the reason that I had it towed there).

The total pre-tax bill was $1051. $771.43 for the clutch actuator. The Mercedes dealer in Seattle apparently didn't have one, so there was an additional $12 to get it shipped from the Portland dealer. There was also a $27.93 shop supply charge. Labor was $52 to diagnose the problem (and attempt to convince the clutch actuator to start working), $162.24 to remove, replace and perform the "relearn" procedure, and $25.46 for "hazardous materials" (under "labor" costs?).

I opened up the old clutch actuator and found that the spiral gear (that is formed into the end of the motor shaft) had broken off. The broken gear matched against the broken shaft, so there wasn't any other broken gear parts in there.

The clutch actuator has a big spring that should push the actuator out and disengage the clutch if the actuator should fail, but the broken gear and something else that I was unable to identify were wedging the actuator in, so the clutch remained engaged and so the car would not roll. I removed the motor and the broken gear, but the actuator would still not move until I started removing the bits inside the housing, and then the actuator popped out from the force of the spring mentioned above.

Since the gear is part of the motor shaft and is under a lot of load, I suspect the actuator would need a new motor to be repaired. If anyone wants my old actuator, let me know.

alan

 

[mildensmart]

How much to ship it to Texas 76248? I have an actuator that the motor doesn't work but the gear is OK. Maybe I can save one.

 

[Smart Bob]

I have taken apart a couple of clutch actuators & they both had broken off the tips on the shaft. The motors on both of them work perfectly. If one can find a good shaft or have one made & properly hardened, you could put re-build these actuators. From what I can see, I think the narrowing of the actuator tip is a weak point and will eventually fail as some have experienced with actuator concerns.

 

[mildensmart]

Is there any way to test the motors separately from the actuator housing? When I plugged the actuator assembly into the car harness, they didn't move but since I don't have a motor/plug wiring diagram I was afraid to put 12V into the wrong circuit to see if the motor was good or the gears were jammed.

 

[Smart Bob]

I used a 12v power supply to test the motor. You could also use a 12 v battery and a couple of jumper wires.

 

[AlanPerry]

Is there a pinout for the connector available?

I would bet that the motor still works. However, I don't see how to repair the shaft/gear. That spring that the actuator works against puts a lot of load on the end of the shaft.

If someone wants my old actuator, my ship-from zip code is 98110. PM me and I'll send my Paypal e-mail address.

alan

 

[Smart Bob]

I hope I still have a defective actuator that I can test in my garage. I'll try & do this tomorrow. They are a little difficult to disassemble and dealing with that spring in trying to re-assemble one is a handful. As far as I know, the hardened steel shaft is not available separately. One would have to have them made up at a machine shop and then case hardened. Next, you would have to figure out an efficient way to re-assemble one. For the number that actually fail, this doesn't seem like a reasonable endeavor unless the part becomes NLA, which I hope doesn't happen.

 

[jimvw57]

Kind of along the same line, when I replaced my alternator, I still have the old one thinking it might be a bad diode or regulator, but I have not had the time to tear it apart or mess with it. If someone wanted it to play with, pay for shipping and you could have it...

 

[AlanPerry]

Depending on what the end of the shaft did when it failed, it isn't that hard to replace the motor. The motor is held in by 2 T35 (I think) machine screws.

In my case, the broken off end of the shaft was in the recess under the motor and easy to remove. However, the geared bell crank part between the spring and the part that pushes on the clutch lever (and that the motor turns) was still wedged in the engaged "clutch pedal released" position (despite the pressure from the spring). I removed the bottom cover (5-6 T25 screws), then removed the clip on the pivot of the bell crank and was starting to pry the bell crank up to remove it when whatever was causing it to wedge released and the bell crank went back into position. I think at that point, it may be possible to install a new motor and the clutch actuator would work. However, I doubt that smart sells the motor separately.

Oh, yeah, the clip for the pivot of the bell crank broke, so a new one of those would be needed as well, but I think a replacement for that could be found.

alan

BTW, my old clutch actuator has been claimed.

 

[Smart Bob]

I looked at a disassembled clutch actuator unit that I have laying around. The steel shaft coming out of the motor snapped off. The motor is a sealed unit and looks like it would be a bit difficult to disassemble and be able to install a new shaft and keep the unit sealed to prevent the intrusion of FOD down the road. I think that the motor could actually be R/R if a replacement motor were available.

 

[mildensmart]

Any chance you have a pin out diagram of the connector?

 

[Smart Bob]

Sorry, I do not have a Pin-out diagram. Hopefully, someone here who has WIS or Alldata will be able to provide you with that information.

 

[mildensmart]

Finally got around to tearing apart the actuator AlanPerry sent me. As described, broken motor shaft. The pinout info is available in this forum http://www.smartcarofamerica.com/forums/f353/clutch-actuator-disected-44190/ and the motor tested good. I have another failed clutch actuator but the brushes in the motor were shot. Anyone ever figure out how to remove the front bearing plate from these buggers so I can swap a good motor shaft between these or replace the brushes?