A Little Vibration Turned Into a Big Lesson in My Cheap Fiat Abarth
I assumed that maybe I needed to learn how to drive the car better. But, no... the car was just broken.
Rebuilding the axles on my Fiat 500 Abarth was fairly straightforward, but unfortunately, it didn’t completely solve the vibration issues I was having. It turned out that there were more broken driveline pieces than I realized, and thus began the next phase in getting this $1,500 hot hatch back to living its best life.
Frustrated with the axle situation, I turned back to the Broken Fiat Club on Facebook and asked for advice. As far as I knew, the new tripod bearings and boots were fine, they seemed to fit as well as the old ones. Or maybe they didn’t — I wasn’t sure if the replacement Amazon Febest bearings were in the exact same spec as what Fiat slapped on at the factory.
Members of that FB group insisted that if axles were not the culprit, then motor mounts had to be the next potential failure source to check. If motor mounts are weak, the engine will shake around, and cause driveline vibrations.
Fiat 500s only have three engine mounts; one on the passenger side, one on the driver’s side, and one underneath. The passenger side mount is hydraulic; filled with fluid to do a better job of absorbing vibration. This mount does most of the work holding up the engine, and higher-mile examples tend to leak and let the motor flop around. On the driver’s side, there’s a big static rubber mount underneath the battery that mounts to the transmission. Underneath the car, there’s a torque arm mount that keeps the whole motor and transmission assembly in place.
Replacement for the top two mounts is very simple. For the passenger side mount, you only need to undo one bolt to move the coolant reservoir out of the way. Then make sure the engine is supported from underneath; a block of wood and a floor jack is enough. From there, you can remove the three simple bolts holding the mount in place. Snatch the old mount away, and replace it with a new one. The passenger side transmission mount is very similar except that the battery, ECU, and battery tray will need to be removed to access the mount. Both sides took me maybe an hour, max, to replace. Most of my time was spent jacking the vehicle up and digging for tools.
Once I had the mounts out, it was clear that two were definitely cracking and showed signs of fatigue. The passenger side hydraulic mount had leaked out some fluid, too.
The torque arm mount was a bit more complicated. To get it the exhaust had to be undone and then hung down out of the way. Access to the bolts holding the torque arm in isn’t ideal, and some of the exhaust bolts might be a bit, uh, fragile if the car you’re working on (like mine here) has lived in a rust belt state. Still, the replacement wasn’t that complicated, the old one came apart easily and the new one slid right in.
With the new engine mounts installed, and the rebuilt axles done, I figured I was finished. Vibrations should be gone, it should be smooth sailing! I was stoked, it seems like in the battle of cheap Abarths, I was poised to come out way ahead of both Yuri from TheStraightPipes (who bought one for $9,000,) and John of WatchJrGo (who also picked up an Abarth, for about $4,000). See, I didn’t need a clutch or expensive OEM axles, you can do everything at home, I figured!
Riding the high, that sweet feeling that I had bested other, bigger, car bloggers, I took my fixed Fiat on its maiden journey with rebuilt axles and new motor mounts. I tapped the Sport Mode button and put my flat on the floor… only for that wobbling vibration to make its presence known again.
Freshly frustrated all over again, I figured there must have still been an axle problem after all. The new bearings I installed on my old axles had a lot of play, maybe the whole axles were moving back and forth on the spline? Or, the other spider joints (the one closest to the spindle) could have been worn out too. There’s no replacement for that spider joint, so I finally had to bite the bullet and buy the OEM axles I’d been hoping to avoid spending money on.
Some $500 later, I had new factory-fresh axles at my front door. Installation was simple, this was now the third time I had removed the axles, so putting brand new ones took me maybe an hour and a half.
Even after replacing both sides with brand new OEM axles, the car still vibrated like hell. But, weirdly, the vibration had become intermittent. Sometimes, the car was flawless, pulled strong with no shaking whatsoever. Other times, it vibrated more than a $29 flight to Miami on Spirit Airlines.
What was wrong here!? Was the engine actually trashed in a way that I didn’t understand, causing vibration in a way I couldn’t possibly see?
At my wit’s end, I went back to the Broken Fiat group and asked more questions. One person said, “My Abarth had a similar vibration. Turns out, my flywheel had gone out.”
I didn’t want to replace my flywheel, but that did feel like a logical solution. The Abarth’s previous owner led an active lifestyle, big dogs, loud music… and Jet Skis that he towed with the tiny hatchback. These cars aren’t rated to tow anything at all, so yeah, it makes sense that the clutch and flywheel could have been well-worn.
I don’t doubt the Abarth had the power to tow close to 1,000 pounds, but are the driveline components designed for all that extra weight? I don’t think so. Still, replacing a clutch and flywheel is a time-consuming job and I didn’t want to replace them until I had to.
Finally, one day while accelerating under full boost, the revs raced, but the car didn’t pull forward any faster. “Hm, that’s weird,” I thought. So I tried it again, turned on Sport Mode, and put my foot flat on the floor. The RPMs revved higher, and the car hesitated.
The transmission was slipping. “Well, I guess it’s new clutch-and-flywheel time after all.”
For those of you who might appreciate a little extra automotive context, this old HowStuffWorks video provides a very clear visual demo of how a clutch works and explains its relationship to the flywheel.
These Fiats have a dual-mass flywheel, and I suspected that the dampening between the two sides of the flywheel wasn’t working correctly. This could be a stuck spring, some debris, who knows, I just knew it needed to be replaced. I also knew that I didn’t want to do the work myself. A clutch job on a Fiat 500 does not seem that hard, but you do have to remove the subframe, steering rack, and obviously un-mate the engine from the transmission. With a two-post lift, it sounds pretty manageable. But I don’t have a lift, I just have a garage and a driveway. No thanks, off to the mechanic it went.
There were some other issues with the Abarth lurking; the drivers’ side inner tie rod was bent, and the front end links looked a bit worn.
My mechanic told me that getting the clutch in was harder than taking it out. These Fiats use threaded dowels to align the motor and transmission; the dowl itself is super long and makes aligning the clutch and motor very hard. You can’t really adjust the transmission when it’s in place, and it’s very easy to align the transmission only to realize you didn’t align the splines for the clutch and flywheel.
Even with some hardship re-mating the engine and transmission, my mechanic had the car apart, and back together in around 10 hours or so, or roughly two evenings.
Now the clutch pedal is super light, and the vibration is pretty much gone. Before the new clutch and flywheel, I had issues getting started in first gear. No matter what I did, I could not get a smooth start in first gear — I assumed that maybe I needed to learn how to drive the car better. But, no… the car was just broken. With the new clutch and flywheel, it’s a night-and-day difference for the better.
The moral of the story is that sometimes it’s a long road to figuring out what exactly is making your new used car behave oddly. This is especially true when you have to re-fix something you thought you fixed along the way. But I hope you get some inspiration here to keep working through frustrations — everything’s fixable, you just need to keep asking questions and eliminating possibilities!
Next up: timing belt.