Why Is The Smart 450 Bucking, Shuddering, when taking off?

[DieselFreak 1]

Hi guys. So after doing a large amount of work on the smart:

- axle seals

- crank pulley seal

- new alternator + bracket

- new belts

- new front motor mount

- new swaybar end links

- new rear shocks

- new rear wheel bearings

it was driving great!

until now..... it has 179000 km’s on it, and from take off, in 1st gear or reverse, it bucks and shudders. It is very jerky. The clutch engages and disengages 3 - 4 times before the car smooths out and takes off, all other gear shifts are smooth, except for the occasional rough downshift. Any ideas?
thanks in advance

[Nigel 287]

My guess would be clutch actuator adjustment or a hole forming in the clutch fork.  I know there was a big improvement on how mine drove the first time Glenn adjusted the actuator.

 

Nigel

[Leadwing 565]

Plus one on the probable need for a clutch actuator adjustment.

 

Once the issue has been solved, town-shifts can be done seamlessly if you manage to match the engine RPM with the anticipated next lower gear.  It takes a bit of practice, since there is no actual clutch pedal, but approaching corners or stops more gently will give you a chance to try it out.

[LooseLugNuts 557]

i would lean more towards the clutch fork punching a hole because you said it was sudden and severe

 

be very careful with those actuator bolts ...they break easy

[Willys 747]

I agree also.....use some heat if need be and a good tap with a hammer to loosen them before possibly snapping them off. I have snapped a few and had to drill them out etc etc.   Not the end of the world but a pain!  Check the threads for actuator issues and see what's involved in cleaning and then reinstalling after checking for that punched through hole in your clutch fork arm.  There is a cheat to get around that also.....install a machined  wider head onto the actuator shaft larger than the hole etc.  OR get a new fork and install in the worst case synario...?   I bought a new clutch assembly from MW-SMART and had it shipped for half what they want for one in North America....!!!!   I also have my old arm here if you want it, no hole in it. IF you change the arm change the throw out bearing also, it'll be a rusted mess I bet.   It's a rabbit hole......lol.

 

[DieselFreak 1]

Thanks guys

[DieselFreak 1]

Sooooo,

one of the bolts broke off. 😡

is it possible to only use 2?

[Willys 747]

NO...!

It's not that hard to CAREFULLY  drill and tap out a new hole and fix it....youtube how to.....seriously....I'll bet it takes a load of torque on that actuator to move the clutch fork lever.  I personally wouldn't try it....I'd try the fix it method first.

Just my opinion .....sorry.

 

[smart142 605]

Usually the head of the bolt snaps off. When the actuator is removed some of the shaft is visible. With heat, penetrating oil and vise grips you should be able to remove the shaft.

[DieselFreak 1]

Ok. Thanks, there is part of the bolt still exposed. I was able to get the actuator off, and there is a hole in my release fork. We drive to much to do the acorn nut mod, so out comes the transmission!

[tolsen 630]

Best way to remove sheared bolts is welding a chamfered nut to what remains of bolt. 

Use next size up of nut  For M6 bolt use M8 nut etc. 

[tolsen 630]

More examples of successful removal of sheared bolts. 

 

 

Sheared M8 bolt removed from an Iseki tractor exhaust. This bolt had sheared flush with surface.  Was short of M10 nuts so used M8 nut bored out to 9mm and chamfered using 11.5mm drill. 

 

MIG is easiest but MMA also fine. 

 

 

 

 

[LooseLugNuts 557]

welding upside down is a wonderful experience 

 

if you have a welder thats the best way though...weld a nut on whats left...the heat really helps

 

much easier to do on a workbench if youre taking out the trans anyway...the acorn nut repair can last a long time but changing out the arm is the best way (just remember to grease it once in a while)

[LooseLugNuts 557]

also while the trans is out it might be a great time to carefully remove and lube up the crank position sensor hole

[DieselFreak 1]

Thanks guys

ill just use the welder once it is out of the car

[LooseLugNuts 557]

might as well add cleaning and protecting the starter spade terminal and inspecting the intercooler too...and that wire harness that always chafes ..and the scoop ...and the reluctor rings...and the ......everything else 

[Willys 747]

36 minutes ago, LooseLugNuts said:

might as well add cleaning and protecting the starter spade terminal and inspecting the intercooler too...and that wire harness that always chafes ..and the scoop ...and the reluctor rings...and the ......everything else 

Now you're talking my language.....lol.

For the extra work it solves so much and hopefully ends most if not all nasty jobs in the future....may I add one to your new list...?   Separate the power leads to the starter and alt. so IF you need to work on one or the other in the future, you can undo the unit and then be able to turn it around to enable you to undo the power leads and not have to fiddle for what seems hours blindly because the two are connected by the shared power cable. Simply run a new cable from the front of the sub frame and make a connection to the two there. Also allowing you to drop sub frame without messing with those power lines ever again.    Also if you wish to, solder the power lead to the trigger and then make the connection away from the spade connector so IF again you need to mess with it, it's in an easy to deal with location.   Just simplish things which in the future will help you greatly if you need to go after either job again......it makes this little complicated car into a K.I.S.S. set up.    Just a thought and won't cost you much at all except the new ends for the cables and a 3 foot piece of #6 wire...?

[LooseLugNuts 557]

my coupe was fairly butchered up when i bought it ...

 

the main power cable had been cut and i used a clamp to repair it...came in handy during subframe removal/installation...

 

it looked similar to this >>> https://www.topothegulfmarine.com.au/steering-cable-clamp-brass-tiller/

 

 

[smart142 605]

23 hours ago, LooseLugNuts said:

also while the trans is out it might be a great time to carefully remove and lube up the crank position sensor hole

 

I would change the crank position sensor.

I've changed 3 in the past year and its a nasty job. They are getting old and starting to fail.

Much easier if the tranny is out

[Willys 747]

14 hours ago, smart142 said:

 

I would change the crank position sensor.

I've changed 3 in the past year and its a nasty job. They are getting old and starting to fail.

Much easier if the tranny is out

I'll second this........worth every penny when the whole assembly is out or separated compared to having to do it with it in the car!!!!     I did mine after I had everything all buttoned back together but not in the car, it was still a nasty job seeing as you can't get anywhere near it with your fingers....! Plus it doesn't want to come out of it's hole easily the first time either.   Spend the money and buy a new one.....you may thank us later.....you can always keep the old one as a spare.....if you really wanted to...lol.

[wagonwheel 2]

On 5/21/2020 at 8:33 AM, Willys said:

I'll second this........worth every penny when the whole assembly is out or separated compared to having to do it with it in the car!!!!     I did mine after I had everything all buttoned back together but not in the car, it was still a nasty job seeing as you can't get anywhere near it with your fingers....! Plus it doesn't want to come out of it's hole easily the first time either.   Spend the money and buy a new one.....you may thank us later.....you can always keep the old one as a spare.....if you really wanted to...lol.

 

Where did you buy your crank sensor? I've seen them on amazon and at germanparts.ca. From $40 to $100 I'm not sure if they are all the same or the more you pay the better the product?

[Willys 747]

1 hour ago, wagonwheel said:

 

Where did you buy your crank sensor? I've seen them on amazon and at germanparts.ca. From $40 to $100 I'm not sure if they are all the same or the more you pay the better the product?

Just make sure it's a well known name brand, IMHO...even check the dealership to see if they demand a nut for it as the hell you are going to go through to get it out isn't worth doing it twice.  Ask me how I also have learned this lesson. It's hard to see it let alone get it out, especially if it hasn't been changed since new.

 

[Mjolinor 91]

Put copper grease on it when you put it back.

[Nigel 287]

You guys are rehashing topics that are years old.

[Willys 747]

1 hour ago, Nigel said:

You guys are rehashing topics that are years old.

Wagonwheel is requiring to change this sensor so is asking which sensor to buy as he is buying one now...I think.  The job is a nasty one unless you are lucky enough to get one that hasn't siezed in the bell housing OR the bolt that holds it in place hasn't rusted enough to cause it to strip when you try and undo it.