September 11

2008 Smart Car Clutch

Smart Car


Mark: Hi, it's Mark Bossert. I'm here with Bernie Pawlik, Pawlik Automotive in Vancouver, Vancouver's best auto service experience, 25 time winners of best auto repair in Vancouver as voted by their customers. We're talking cars. How are you doing Bernie? 

Bernie: Doing very well. 

Mark: So today's victim is a reprise, the miniest car in the world perhaps, a Smart Car, 2008 version that had a clutch issue. What was going on with this car? 

Bernie: So this vehicle, the owner had noticed an issue, mostly when the vehicle is cold. It tended to miss some gear shifts and when you put it into reverse, it would make a grinding sound, like a kind of clunk, like a real rough engagement. These vehicles, just to put some context, it's an actual manual transmission car, but it's automatically shifted. 

So there's no clutch pedal in this vehicle. There's a clutch actuator that electronically shifts the gear. So as the vehicle speeds up, it'll determine, okay, it's time to shift the gear and the actuator will basically do what your foot would normally do with a clutch pedal and then the transmission shifts the gear.

So again, it's a pure manual transmission with an electronic actuator. Design's been around, I think Volkswagen used it back in the 70s or 80s, yeah, 70s, I think they had one on some models. But Smart Cars use them, except for the EV models, they've used them for pretty much everything else. So that's basically what we were dealing with. 

Mark: So what sort of testing and diagnosis did you do? 

Bernie: We did some scan tool diagnosis and testing. The clutch actuator can be activated through a scan tool. So we did some tests, there's some initializations and parameter setting. If I'm using the right word for the actual clutch actuator to make sure everything's set in the right position. There are actually adjustments you can make on it. We kind of assumed that it's either gonna be inside the clutch or it's gonna be the actuator.

So we were not able to get the actuation set up properly, so, we pretty much determined the first place to start with the repairs in this vehicle was to replace the actuator because it wasn't responding as it was supposed to. So that was the first repair we proceeded to do. 

Mark: And what was involved in replacing the actuator?

Bernie: So we got an actuator, we put it in. It required reprogramming for the vehicle. So we did that, had it all set up and working fine. My technician who did the work, took it out for a drive, said, yeah, it seems to be better. I thought, hey, well, I'll road test it. So I went out and drove and I go, wow, it feels fantastic.

 It's not grinding into reverse. All the gears are shifting smoothly. Everything feels really good. So problem solved, you know, customer picks it up and we're done. That was kind of how that went down. 

Mark: And so then, did something else happen? 

Bernie: Yeah. So the next day he called and said, Hey, it still grinds into reverse. And I thought, Oh, that's kind of weird. And I know the issue that he originally had was when the vehicle was cold. So he brought it in and sure enough, it did feel better than beforehand, but when it was stone cold and you go to put it in reverse, it would make a kind of a crunchy engagement.

And it seemed to shift better in forward gears, but the reverse issue was still there. So we basically suggested to him, you know, you might want to live with it for a little bit. See if it, you know, improves at all. It didn't. So you know, a few weeks later we proceeded to the next step.

Mark: And that was? 

Bernie: That was, we figured it was time to actually look at the clutch itself. We again, rescanned the vehicle, the actuator was working properly as it was supposed to. So the problem could only have been in the actual clutch itself. So we basically proceeded to replace the clutch.

Mark: So what's involved in replacing the clutch on such a small vehicle? 

Bernie: Yeah. I mean, it's basically the same as any other Japanese, this is a transverse mounted engine in the rear of the vehicle. So it's actually a fairly straightforward removal. You basically pull the transmission out like you would on any vehicle with a clutch replacement. Pull the transmission out and access the clutch. And the clutch is basically kind of the same as any other clutch that you would operate with a pedal. The only difference, of course, is the actuator replaces the clutch slave cylinder. So that's kind of what we did. 

I'll show some pictures of a few items here while we're talking. So there's our cute little Smart Car. Nice bright yellow vehicle, hard to miss on the road kind of vehicle. 

2008 Smart Car Clutch

We'll start with the clutch actuator. So this is a photo of the clutch actuator. This is the old one that we took out of the vehicle. This end here, as I mentioned, there's certain settings. So you can actually physically adjust this actuator, you can see these, my mouse pointer moving around, slots in the mounting. So you can actually adjust the position of the actual actuator. This is the actual plunger, the piece that moves in and out.

2008 Smart Car Clutch

And the solenoid, this is the motor that actually operates the actuator. And then there's wiring connections here, of course, power to do the actuation and verify that the things are moving as they're supposed to. 

This is the view of the other side of the actuator. Not so much interesting. This plastic cover here is actually removable and we can have a look at what is on the inside of it. 

2008 Smart Car Clutch

So there's your actuator plunger. This is the arm that moves there's a big counter say counterweight spring, but it not a counterweight, but you know, obviously it keeps the motor from ...sorry ...return spring? It's actually not necessarily a return spring. I think it's to balance the pressure of the motor and against the clutch. And this is the actual actuator arm here. So this would move back and forth as the clutch is powered on and off. Basically doing the work of your foot. 

2008 Smart Car Clutch

So getting into the actual clutch itself. So what we found when we took everything apart is the clutch itself was quite badly worn out. And for some reason, I forgot to take a picture of the clutch disc. But this is a picture of the new clutch disc. And if you look kind of carefully, these are the rivets that hold the friction material onto the disc.

2008 Smart Car Clutch

There's material on both sides of this. If I flip the disc over, there's friction material on both sides. But there are rivets here. And as things wear down, the friction material will wear right down to the rivets. And that's exactly what had happened on this one.

It had worn right down to the rivets, which is basically the clutch disc was worn out. But in addition to that, I mean, when the disc gets worn out, usually what happens is the clutch will slip. So when the clutch would engage, the engine would rev up, but the vehicle wouldn't move. That wasn't happening in this case, I mean, the clutch was getting close to that point, but what was probably worse was this area here. 

So this is the clutch fork and the actuator pushes on this area here where my mouse pointer's pointing. This is the clutch release bearing. So this pushes against the pressure plate, that releases the pressure on the clutch and then it allows it to shift gears. But this is all gummed up. You can see it's, it's kind of rusty. It's not moving very well. And when you buy the clutch kit, it comes with all these pieces. So normally when you replace a clutch, it often either comes in individual pieces or a kit. And the kit will usually include the release bearing, this piece here that I'm moving the mouse pointer on, the pressure plate and the disc. Usually comes with those pieces.

2008 Smart Car Clutch

But this kit was even more deluxe. It came with a new clutch release fork, this part here and this collar here where the clutch release bearing slides. So basically all the clutch moving parts were all replaced, which is really good. What else can I show here for pictures?

2008 Smart Car Clutch

Oh, yeah. So the flywheel. The flywheel is the other end of the clutch. This is the flywheel is on the vehicle. It's a single mass flywheel, so it doesn't need to be replaced. It can be ground, but you can see the sort of mark here. That's where the rivets were rubbing against the flywheel. You can't really see on this angle of the picture, but the surface is not entirely smooth across the surface. Like like you see in this picture here. 

And this is the same flywheel. It's just been re ground. So we take it to a shop that has a flywheel grinder and it grinds a little bit of metal off the flywheel, not enough to affect the performance, but it basically puts a flywheel into brand new condition. So, I believe that's the entirety of our picture show for today. 

2008 Smart Car Clutch

Mark: So, what's the advantage of using electronically actuated shifting for the clutch? It's not even shifting. The clutch operation, and then you still are rowing to get the gear changes happening. What's the advantage? 

Bernie: Well, I think the advantage is that standard transmissions are more economical than automatics because there's a loss of, I don't know the exact number. It's 2 or 3, maybe 5% of the powers lost within the torque converter. Now the way they eliminated that is that a lot of torque converters lock up. They have clutches inside them that will actually lock the torque converter, but that doesn't happen right away. 

So it's more efficient to have a standard transmission than there is an automatic, but of course, it limits the skill and you have to be able to drive a standard. Lots of people can, but lots of people can't. And it's probably an efficiency thing. It's just a little more efficient on a car, that's a tiny little car, getting sort of the best economy out of the car. But it's a weird feeling. 

When you're driving a Smart Car, it's like, kind of jerk back and forth every time it shifts gears because the shifting is, there's this delay, it just doesn't have the finesse of a human being operating the pedals. Sometimes, but yeah, sometimes, yeah. Well, some people are not good standard drive, but most people who drive a standard after a while, get very good at it. You know, it's just the delay in the way that the shifter and the actuator works.

And you know, you can manually shift these things too. So you could actually be in control of it, but still nonetheless, the clutch is done electronically. And so it has that time delay.

Mark: It's awkward. I drove a V10 M5 BMW that had this, and it was like, what is wrong with this vehicle? 

Bernie: Yeah. I know exactly the car. I've driven that same vehicle and it's really not a very comfortable feeling like that BMW. I'm going, you know, what's the advantage to that? Either make it a stick shift or make it an automatic. Because automatics don't really have that delay, they're snappy, they shift fast. Especially in a performance model, automatic transmission.

Mark: So I just have a question about the shifting. So the shifting is determined by the engine RPM and the wheel speed? 

Bernie: Yeah, it's both. Yeah, there's a computer that kind of calculates that out. You know, as the vehicle speeds up, you know, the engine RPM will get to a certain point and a certain load. And then the computer will determine, hey, it's time to shift gears. With a manual transmission, you're the one who makes that determination. 

And I find a lot of people shift gears way too early, and if I'm out driving, people shift way too early. I think in a standard, you should actually rev the engine way higher and then shift. But, you know, it's probably more fuel efficient to shift at a lower speed. But from a point of view, like for maximizing the engine performance and actually the health of the engine, it's better to rev it up and then shift than it is to shift in really low speeds. 

Mark: So once you replaced the clutch, how did everything work?

Bernie: It was awesome. Like it was fantastic. You go into reverse, you can't even tell it's into gear. So it was like a night and day difference. I mean, that was kind of like the benchmark. And, you know, after it had been fixed, I go, okay, I'll take it out for drive. It felt perfect. And I thought, let's just keep it overnight because I don't want to give this back to the client and have him call the next morning and go, hey, it's still buggered up. So we kept it overnight. Beautiful. It was like a dream, but you know, I say it's like a dream. It still has that jerky feel, but it actually took the jerkiness out a bit, but it still has that feel. 

The only Smart Cars I really like to drive are the EV ones. Cause they're just smooth acceleration and deceleration. They don't have that jerky feel. 

Mark: So why not replace the clutch in the first place? 

Bernie: You know it's kind of like you can't see the clutch. It's hidden. And if the vehicle was slipping, you know, when say you accelerated and the vehicle would slip, you know, if you ever owned a vehicle that has a worn out clutch, say you're going up a hill and you go to shift it into gear, you go from 1st to 2nd. Also, the engine goes and then it engages, you know, the clutch is worn out.

This wasn't doing anything like that. So we have to, you know, take an educated guess and use the tools we have. And so based on the tools we have, it seemed like the actuator was the first place to start with. And in fact, the actuator was bad, it may have been the bad actuator that it caused the clutch to wear out and not shift properly in the first place. So you have to start somewhere. I mean, had we said, okay, let's change the clutch itself first, the actuator would need to be replaced afterwards anyway. So, you know, it needed both. It's just like, why not take it 1 step at a time and take the best guess. 

Mark: So a 2008 Smart Car. How reliable is this generation of Smart Car? 

Bernie: Yeah, they're pretty good. You know we do repair a number of repairs on them, but they're generally pretty good. These aren't the most long lasting cars, you know, by the time you get a hundred thousand kilometres on these cars, they tend to be kind of old. I mean, we see Volvo's with two or three, 400,000 kilometres and Subaru's way up there and Honda's, Toyota. But it seems like Smart Cars by the time you hit 100, they seem to be a little old. And this one only had 85 on it too, kilometres. So it's not a lot. So they tend not to last as long as other cars without needing a lot of repairs. But once the clutch was done, car worked really nice.

Mark: Great in town car to get you back and forth to work. 

Bernie: Yeah. You know, I do have one comment though I will make is they actually drive quite nice in the highway too. For a little car that's just, I mean, so small. These cars are really well designed, they actually feel quite comfortable to drive with on a highway, which I think is a real achievement.

And you know, apparently from a safety point of view, they're actually very well designed. They're actually quite safe. Although, you know, if you get hit by a, you know, I don't know, like a bus, a bus, well, you're toast in any car and a bus. But if you're hit by a large vehicle, which pretty much everything is, it's going to go flying, but the passenger compartment is very solidly designed. So for a little tiny car, they're actually quite safe. 

Mark: If you love your Smart Car in Vancouver, the guys to see to get it repaired are Pawlik Automotive. You can reach them on their website You can book right there. Or you can call them (604) 327-7112. You have to book ahead. They're always busy. Pawlik Automotive in Vancouver, BC, Canada. Thanks so much for watching and listening. We appreciate it. Thanks, Bernie. 

Bernie: Thank you, Mark. Thanks for watching.

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Bernie Pawlik

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