Trick question. There has been no crash of Malaysia flight 360.

Point taken that investigation experience of the degree required here does not exist with people that work at car dealerships or senior techs at the factory.

It is a very specialized field.

 

Three things worth noting when folks are rending their opinions. First, driveshaft vibration is absorbed by the rubber couplings. So you could have an unbalanced driveshaft but if you're driving around town at LA traffic speeds you may never know it. Second, a crease in the metal, and we are talking metal that's apparently just 1/16" of an inch thick (i.e., super thin) may not cause a rotational imbalance of any great consequence at all. Take a soda can and with a pencil draw a thin crease in the metal. It's not going to throw off the rotational balance noticeably but it will decrease significantly the structural integrity. Third, with metal just 1/16" of an inch thick ALL the driveshaft's strength comes from the integrity of the circumference's circularity. Defeat its geometric strength and it simply collapses. Here's another guy whose driveshaft blew up. All he did was put it in reverse. You can see by the metal just how soda can thin it is.....and that was a shaft used on a truck! http://www.reddit.com/r/Justrolledin...shaft_failure/

 

A fourth thing worth noting is that a small defect in a driveshaft's surface will not cause it to fail within 30 miles of typical driving.

 

I hate to even ask this, but did you verify the odo when you dropped it off (usually on ticket) and what the leaving mileage was?

Just had a thought that 30 miles might really be 50 or 100 if the shop was out joy riding / abusing the thing.

Agreed on Mikey's fourth, an impact that significant to cause a subsquent failure would be huge, and the driveline would not be able to absorb the same IMO, you would have felt it at higher speeds (am guessing) at minimum.


Jeff

 

Hi ExcelsiorZ,

Another thing to note about the forward end of the driveshaft is that it is very close to the transmission mount, which could further suppress any noticeable vibrations that might have been caused by any degree of damage done to your driveshaft by the shop. It is possible that damage made very close to the forward end of the shaft might cause no noticeable vibration at all, but could significantly weaken the thin tubing. I use italics intentionally to emphasize the conjecture I feel is reasonable when discussing your case. The number of theories expressed here as "certainties" is truly astounding.

For the record, I'm still on your side. The circumstantial evidence of shop damage is strong. But I hope you are able to find conclusive evidence to help us understand what caused the failure, and if possible, to reduce your financial loss.

And if you get to the point where you need an expert opinion, I would strongly recommend you seek out an expert who hasn't already made up his mind based on assumptions of what is or is not possible.

Cheers,

Don

 

I'm curious for an update on this.

 

Thanks Don.

Here's the update. The Bureau of Automotive Repair came out and inspected my car. Unfortunately the Inspector said "there's no law against bad work" and "our agency has no teeth in this area" and further "there are no qualification requirements in California so anyone can call themselves a mechanic."

This is really a no brainer. I've worked on cars for decades. When I was 20 years old Peter Wheeler and his company, TVR, flew me to England where I would work at the Blackpool factory---sharing with them my special 5.0 litre build for the Rover V8 they were using. I've built and modified many a car over the decades.

The shop f'd this up, plain and simple. My car was / is pristine underneath. It has just 70k miles. Pampered and in pristine condition.

30 miles after leaving the shop the driveshaft breaks while accelerating from a light in a line of traffic on a busy LA street.

People can play devil's advocate, but as we say "res ipsa loquitur" .....the thing speaks for itself.

Surprise, after installing a second hand shaft in my car (which looked no where near as nice as my original shaft) I have had no problems with my driveshaft and have driven the car several hundred miles.

The shop did this to my car. Period.