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Clutch Actuator Story

3344 Views 12 Replies 5 Participants Last post by  twcom
I have a 2008 Passion with 75K miles on the clock. For about two years the actuator has made a slight clatter sound when driving less than 5 mph (parking, looking for a spot, etc). Every 6 months I removed the actuator and lubed it well inside, it would go quiet for about 1K miles and start making the noise again. Then about the beginning of this year it started engaging the clutch VERY hard as soon as I let off the brake; it was the same as if I had “side-stepped” the clutch pedal. This led to almost rear-ending a few cars in traffic. I made several adjustments without success. This hard engagement would last a day or two then everything was fine for a couple of weeks and the cycle would repeat.

I felt the problem could be one of 4 things, (pressure plate sticking, clutch fork sticking, throw-out bearing sticking, or actuator sticking). Then I thought of motor mounts (alignment of eng & trans) and sure enough they were bad. I replaced them and had the dealer put the car on their Star machine to look for patches and actuator/clutch settings. Settings were good and a patch was added. All was good for about 2 months and then I had another hard engagement event which lasted two days.

In thinking through the next steps I felt if the problem was in the pressure plate, clutch fork, or throw-out bearing it would happen almost consistently due to their mechanical nature. So I chose to replace the actuator. I found a guy on e-Bay that has several actuators that are brand new, in the box from SACHS (MB’s supplier) for $319; significantly less than MB or non-china parts houses. When the part came it was still sealed in the original SACHS box, and was clearly brand new.

I installed the new actuator and adjusted it per the FSM, which says to push the actuator up to the clutch fork, then push in 3 index lines more and tighten. The clutch engagement is smooth and crisp and drives like a new car. I did not see any need to return to the Star machine for fine tuning (as the FSM says to do) because everything works fine.

It has been two weeks and several hundred miles since I installed it, so it is too soon to say the phantom engagement is gone for good, but there is no more clatter when creeping in gear.

I write this in case any of the information is of help to others.
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As there now seem to be a decent amount of under 200 dollar actuators on the market. I have been entertaining the thought of purchasing one while my current 2014 original still appears to be in good shape. If money was no object I would buy 2 and send one off to the EU to have one "Optimized" thought the other one on and be confident that the original could be there if there was any issue and need.
Do it is refreshing to see that your replacement and instruction following gave you good results so far.
Question 1.. in this process did you have the battery disconnected. ? And question 2 .... did you perform the " transmission/throttle reset in conjunction with the final Clutch Actuator installation?
As there now seem to be a decent amount of under 200 dollar actuators on the market. I have been entertaining the thought of purchasing one while my current 2014 original still appears to be in good shape. If money was no object I would buy 2 and send one off to the EU to have one "Optimized" thought the other one on and be confident that the original could be there if there was any issue and need.
Do it is refreshing to see that your replacement and instruction following gave you good results so far.
Question 1.. in this process did you have the battery disconnected. ? And question 2 .... did you perform the " transmission/throttle reset in conjunction with the final Clutch Actuator installation?
I would be cautious about where a new under $200 unit was manufactured, I have heard horror stories about the low cost units.
1) I did not disconnect the battery, altho I made sure the the actuator was fully retracted before working on it.
2) No. From everything I have heard the MB reset process does not work for Smart, it seems they did not include fuzzy logic in the Smart transmission software. If someone knows differently please let us know.
The clutch actuators of both my 2012 and 2008 will have a hefty kick on engagement (like someone dropping the clutch in a true manual) if I drive the cars hard. It'll sometimes happen after a full throttle run to top speed, offroading, or towing trailers. The issue always eventually clears itself up so it doesn't bother me. Good to know it's actually the actuator doing it!

I figure a new actuator would fix the issue indefinitely...at least until the new one gets some years and a hundred thousand or so miles on it. :)
My 08 has done it since day one. I just feel it's the computer being a bit confused. Like Miss M said it always seems to go away.
Very interesting that Slivers & Miss M have had this occur for sometime, especially with it happening since Slivers' car was new. I guess I just was lucky for 74K miles and it may come back on my car.
Closing in on about 140k miles on my original actuator, never touched it, no plans to do so unless it needs replacing. The only owners I know of with issues/failures, were the ones who mucked about with theirs.
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One thing a lot of people forget about is how the car is driven. Around town the clutch "may" be used 50-100 times were as driving on the highway maybe 10-20 times. I replaced my worn out dog bone motor mount bushing with a little bit tougher mount here recently and it does shift a bit different after that. I have a 1970 Bronco with a "three on the tree" that I plow snow with and the original clutch made it to 110,000 miles before replacement, just depends on how the clutch is used.
Slivers & Miss Mercedes, when your cars have a hard clutch engagement, is it as soon as you let off the brake or when you start to apply gas?
Both. Originally it was just letting off the brake after a stop, now it's only when throttle is applied.

But to explain, it's because the creep mode function that emulates a torque converter is disabled in both of my 451s. My 2012 has occasionally been doing the hard engagement thing since around 40k miles. Dealership said it's the nature of the beast. It has 170k now and still runs and drives like a champ, so I suppose they were right. In roughly 2018 or so my reluctor rings rusted out, permanently disabling ABS/ESP and the creep mode function. I like how the car drives without creep mode (feels even more like a manual), so I've just never replaced the rings.

Now during the hard engagement events it only occurs when throttle is applied. That's because the clutch is only now engaged when throttle is applied, like a Euro spec smart.

My new to me 2008 is the same way, but as I haven't owned it since new I don't know how long it's been happening. I've temporarily pulled Fuse 11 for my offroad rallies, so as of right now it drives like my 2012.

But the hard engagements always go away. It's as if the shift computer makes an adjustment or something and the car goes back to "normal".
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Well I will tell you when it happens to me and a few on my Smart owning friends.... Our cars will be just the way we like them cruising around. Then for what ever reason ( being cute, showing off, flooring it to merge into traffic) we over rev the engine usually 1st to second gear. Immediately after that the car bangs into rear as soon as we lift off the brake.
The worst shape the motor mount is in the worse the feeling. If we are rolling in traffic together we will usually call each other and pull over to the side as soon as we can to do the reset rather than let it bang like that, It will eventually settle down but if we have time we just pull over because it just sounds and feel so painful to our babies. the car now returns to a real soft shift state and we just drive off with no additional issues. 90 percent of the time the reset takes and I am a believer of the reset/relearn process. The Smarts are Mercedes engineered and have a lot of Mercedes Benz logic applied to them. The adaptive transmission adjust to the driver by monitoring last 40 shifts.
So with out the reset it will eventually average its self out over the next 40 -80 shifts to get rid of that high rev spike.
Anyhow glance at a few vids and imagine you Smart in terms of just another Mercedes product for a moment.


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twcom - I had tried this reset approach at least 6 times when it first acted up with no change. And you are exactly correct, it sounds like the trans is going to be ripped right out of the car.
Damndest thing thing too, once its reset its like nothing ever happened.
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