Fiat recalls 500e cars over half-shaft bolt issues

"Mosqvich" (mosqvich) 08/15/2013 at 11:07 • Filed to: 500e, half shaft bolts, Chrysler, Fiat

0

36

At this point Fiat has recalled around 271 of its 500e electric vehicle. The issue revolves around half-shaft bolts which according to Chrysler transfer torque from a vehicle’s gearbox to its wheels.

The Pontiac GTO had similar issues, with owners hearing a loud thunk under the car or a nasty grinding sound. One poster on a GTO forum said "luckily it happened as I was going really slow so the half shaft didn't turn into an arm of death swinging around and destroying everything in it's path." What many GTO owners had done was to remove the bolts and use Loctite to ensure their half-shafts didn't break. After all nobody wants an "arm of death swinging around." Pontiac never issued a recall on the problem according to reader !!!error: Indecipherable SUB-paragraph formatting!!! .

According to Chrysler an investigation was launched when the company learned a customer’s vehicle exhibited power loss. Engineers discovered two assembly steps had not been properly completed; creating a condition that could lead to half shaft separation. Chrysler is covering all costs to repair the problem of approximately 270 owners and will provide total numbers to the National Highway and Traffic Safety Administration (NHSTA).

The Fiat 500e has accrued excellent !!!error: Indecipherable SUB-paragraph formatting!!! because of its drivetrain redesign incorporating the bits and pieces needed to turn the 500 platform into an electric car. Jalopnik's Jason Torchinski points out:

!!! UNKNOWN CONTENT TYPE !!!

"Interestingly, this is one of the few cars I've driven that are electric converts from gas models where the handling characteristics get actually improved. The original 500 has a very nose-heavy weight distribution of 63/37 front to rear, while the 500e has a nearly optimal 53/47. My idiot savant readers may recall that that's the exact same weight distribution as the !!!error: Indecipherable SUB-paragraph formatting!!! ."

!!! UNKNOWN CONTENT TYPE !!!

Of course he didn't experience any "swinging arms of death" which probably helped in Jason's characterization of the diminutive eCar.

RamblinRover Luxury-Yacht > Mosqvich 08/15/2013 at 11:14

4

*puts on hat of engineering snideness*

Any time the bolt itself is the shear element in a case like this, ur doin it rong. The job of a bolt is generally supposed to be to provide sufficient clamping force that the flange surface, et al, transfer torque and not the bolt itself, except as part of the system overall.

Sparf > Mosqvich 08/15/2013 at 11:15

3

Do my eyes deceive me or are the half-shafts unequal length? I remember reading about torque steer in FWD cars and how unequal length half-shafts are often a major contributing factor to it.

Arch Duke Maxyenko, Shit Talk Extraordinaire > RamblinRover Luxury-Yacht 08/15/2013 at 11:19

2

Time to up the grade of the bolts. Also remember that you want the bolts to fail before the more expensive parts do.

RamblinRover Luxury-Yacht > Arch Duke Maxyenko, Shit Talk Extraordinaire 08/15/2013 at 11:24

1

True, but if the bolts are going to fail, "sheared axially" is better than "were gnawed through sideways". One of those things means a bad/undersize bolt, the other means bad installation or slipshod/clownshoes overall design.

Arch Duke Maxyenko, Shit Talk Extraordinaire > RamblinRover Luxury-Yacht 08/15/2013 at 11:29

1

yeah in this case, if I'm reading this right, then Juan must have forgot to either torque the bolts down or he forgot the lock washers.

RamblinRover Luxury-Yacht > Sparf 08/15/2013 at 11:32

3

Yep, unequal, though not very large diameter. A big contributor to torque steer is the J or rotational moment of inertia of an element on one side or another. Torque = J*rotational acceleration just like F = ma, so the resistance one side or another gives to the spider gears is directly proportional to its rotational moment of inertia. A half shaft just slightly longer under brisk acceleration imparts more resistance to that side before it even gets to the wheels. That means the amount of torque you get at the wheels after all that will be unequal, and thus - torque steer.

An exceptionally clever designer of a longitudinal FWD might deliberately use unequal length to give a balancing effect to engine roll under acceleration, though that's a dodgy way to approach things.

CalzoneGolem > RamblinRover Luxury-Yacht 08/15/2013 at 12:41

0

Ramblin droppin' science all over oppo

HammerheadFistpunch > CalzoneGolem 08/15/2013 at 12:47

0

I was wondering what that smell was...carry on.

RamblinRover Luxury-Yacht > CalzoneGolem 08/15/2013 at 12:47

0

The explanation's a bit vague, and some bits are really only half-remembered.

April_N_ > Mosqvich 08/15/2013 at 12:50

2

Serious question. What are everyones opinion on the fiat 500e?

I am REALLY tempted to get a lease on one, $200 bucks a month for a nice daily driver that lets me use the carpool lanes is REALLY tempting....

jphamilton > Mosqvich 08/15/2013 at 12:52

1

I am a GTO owner - a recall was never issued however, just a TSB. I had the problem on the way to work when 2 fell out. Dealer wouldn't replace under warranty and wanted to charge me for a new diff. I had it towed home and fixed it for $28.

I also own a half ton Ram which just issued a recall for the same issue.

CalzoneGolem > HammerheadFistpunch 08/15/2013 at 12:52

0

Bad news! It is your turn to clean up after him.

KurwaMac > Sparf 08/15/2013 at 12:54

0

My VW has unequal halfshaft lengths also. Kind of a b*tch to attempt to center a transmission is such a small space.

FZappa > Mosqvich 08/15/2013 at 12:56

1

Wow, a Italian car with build quality issues. I really don't need to point this out

Mosqvich > jphamilton 08/15/2013 at 12:59

0

I saw that they had a Service Bulletin, but couldn't find it. It does appear they didn't actually recall it. I'll fix that. Thanks for the tip.

Mustang 'DontHitTheCrowd' GT > Mosqvich 08/15/2013 at 13:00

1

This happened to my friend's modded Jeep.
I saw the aftermath, it wasn't too bad but man the thing was spinning so fast at the start that it dented his skid plate.
Fixed her all up though!

Straight6PackRacing > RamblinRover Luxury-Yacht 08/15/2013 at 13:14

0

Most driveshaft bolts transfer torque from bracket to diff. The drive shaft does not mechanically lock into the diff, thus creating the 'weakest' link in the driveline. If something goes cra cra, those bolts will fail. And thats a good thing!

RamblinRover Luxury-Yacht > Straight6PackRacing 08/15/2013 at 13:29

0

Good to know. One still would assume, though, that a little bit of interface is called for (but below the strength limits of the bolts), just so the collar *can* "slip" to the bolts under heavy load and shear as-needed, but a constant forcing of the interface doesn't occur.

I suspected it was compound, because most driveshaft bolts are shouldered, but it's good to hear that's usually a function of their role in a system. That still indicates something amiss here, possibly even clamping related, because as long as there's any part of the load on the flange, a deviance from spec will snap things.

Of course, I know of a vehicle that shears axle shafts instead of driveshaft bolts, though I'm not sure that's intentional...

merged-450547912-my6ab > Mosqvich 08/15/2013 at 13:35

1

I can see the ads for the "Improved" 500 now... "Buy a Fiat and Get the New Shaft!"

Acidboogie > RamblinRover Luxury-Yacht 08/15/2013 at 13:59

0

could you not balance unequal lengths by having unequal shaft diameters?
(I'm no engineer, though my job title was once Engineer Scientist)

RamblinRover Luxury-Yacht > Acidboogie 08/15/2013 at 14:23

1

Over certain rev ranges, yes, probably. The trick there is that the spring coefficient of the two shafts would then be even more different. A short thick half-shaft would be like a rock, while a longer thinner one would twist slightly off the line. So the exact same scenario in which you see torque steer from accelerating the shafts might see brief shaft deflection torque steer unless both were overbuilt. It's an interesting thought.

As another note, the so-called revo-knuckle that Ford developed was very useful for "pulling straight" torque-steer correction, so combining something like that with equal length shafts (for "veer-to-one-side" torque steer) is probably the best overall solution.

Straight6PackRacing > RamblinRover Luxury-Yacht 08/15/2013 at 15:14

0

I have blown out shafts over bolts while racing; but those were due to poor trailer loading techniques. If you dent an alum driveshaft, it will blow up doing 130 mph around the front stretch. Sad day.

I wouldn't call the bolt shear is common in the least. But I am happy know that there are four bolts that will fail ahead of a transmission spline.

TiredAndSleepy > Mosqvich 08/15/2013 at 15:25

1

I snapped a half-shaft on a VW fox once. Luckily I was making a low speed u-turn and it was just a quick pop and then no more go.

RamblinRover Luxury-Yacht > Straight6PackRacing 08/15/2013 at 15:25

0

Here's the character in question I mentioned shearing. Series II Land-Rover, rear half-shaft, usually left side.

Usually the shear occurs at the third-member end, leaving the splines in the diff. The cure is pulling the shafts and then the third-member to retrieve it. Messy, but better than breaking anything more serious.

Mosqvich > April_N_ 08/15/2013 at 15:31

0

I've hear a lot of good. It's not a screamer, but has been reviewed as being an even better 500 because of the weight balance and low center of gravity. I've read reviews where it is considered on par with Tesla in this area, clearly it won't have Tesla's level of quality. Let us know if you do get one.

mrecount > Mosqvich 08/15/2013 at 15:49

1

Cmon, there's like one moving part.

April_N_ > Mosqvich 08/15/2013 at 16:28

0

The only problem is I currently have an RX8 that's almost paid off, and I'm not sure I want to get rid of it.... and I'm not sure I want to pay insurance on two cars.... but I think how much I'll save on gas and it's tempting.

brandondrums > RamblinRover Luxury-Yacht 08/15/2013 at 16:31

0

Well, Subaru had FWD cars in the 80's and 90's that were essentially that. Even their modern automatic transaxles are extremely FWD bias. I don't think the engine roll quite comes into bear even in the turbo models. Perhaps that's just the engines being low and wide and therefore having engine mounts that give good leverage against engine roll.

brandondrums > Mosqvich 08/15/2013 at 16:34

1

Here's my question: We have half shafts that last 200k miles of all lengths and sizes. Why is Fiat re-engineering the CV joint again? Honestly you'd think they'd just use the same manufacturer everyone else uses for that stuff.

So many recalls for proprietary parts these days. Save the innovation to the parts that actually net an improvement to the vehicle. I don't want to see inverse threaded bolts or liquid filled wiring harnesses unless it does something useful.

God I hate modern cars.

Mosqvich > April_N_ 08/15/2013 at 17:12

1

And oil ;-)

April_N_ > Mosqvich 08/15/2013 at 17:24

1

And tires! I'm betting fiat 500e tires will be a lot cheaper than the sticky stuff I put on my 8 lol.

Mosqvich > April_N_ 08/15/2013 at 18:24

0

I'm astonished at tire prices. I haven't gotten any decent tires for less than $800 for my flippin' Ford Fiesta!

April_N_ > Mosqvich 08/15/2013 at 18:51

0

Wow! What size tires does it use?

I spend ~$1k on my car, but it's 225's. And I got super sports.

Mosqvich > April_N_ 08/15/2013 at 20:26

0

17" - I usually get Michelins.

RamblinRover Luxury-Yacht > brandondrums 08/16/2013 at 09:11

0

The classic Olds Toronado was a big-block GM motor in longitudinal FWD on soft mounts, with lots of torque and a lot of engine weight up high. I'm not sure just how much disproportionate shaft length would have been needed to make it behave.

redmouseball > Mosqvich 08/18/2013 at 15:24

0

I would LOVE to have that drive train for a kit car project