Driveshaft Safety Loop

[digithead]

Question for all. I was talking with a local mechanic about adding a driveshaft safety loop at front end of driveshaft. He said on the convertible
Mustang I didnt need it because on the rag top there is a stiffening brace of some sort across the body that would serve the same purpose?
I dont have a lift and quite honest can't see under there well enough. Anyone have a picture of underside that explains this ?  
I had planned on getting the bolt on type loops.

[Jeff73Mach1]

He is partially correct, the stiffening plate that runs across the bottom side of the tunnel will catch a driveshaft with a broken U joint, but if it snaps the front joint, then the shaft will continue to rotate while the car rolls to a stop. It can easily come thru the floor and kill you, but the car won't pole vault.

Make sure if you bolt one in that you bolt it to something solid, not just floor sheet metal.

[87fox72mach]

Do you plan on racing this car? Seems extreme if it's just a cruiser

[Carolina_Mountain_Mustangs]

I can tell you it will shake your teeth out if it does break or come loose. I was going down the interstate doing about 65 mph in my 1950 Ford in about 1970. I heard something hit the floor board and then all H%&& broke loose. One of the retainer clips on the front U joint came out and then the cap came out so there is like 1/4" play in the joint. It flopped around and then came apart. The emergency brake cables were the only thing that saved me. The driveshaft flopping around under there broke the cast iron tail shaft on the 3 speed transmission. It shook the car so hard it popped the hood latch but safe catch caught it. It blurred my vision it shook the car so violently.
The plate your mechanic is talking about is pretty beefy, 3/16" thick maybe with 6 I believe 5/16" bolts holding it up to the floor. It would sure help.
In the 60's before they required the safety loop on race cars a friend of mine flipped his car end over end three times and he woke up in the hospital. Front came loose and shaft stuck in asphalt and pole vaulted the car into the air probably doing 80 mph on a circle track.
I am putting a loop on my 72 Q vert along with a 6 point roll bar since I will be on road coarse and drag strip with it. Will also have a scatter shield over the flex plate torque converter. I have seen flywheels come through the floor, dash and out the windshield. Also cut the steering column and headers into. He was lucky did not loose a leg or foot. It was a new bone stock 289 K code at the Asheville drag strip.
If you ever have one come loose or break you will remember it.
The pictures are of a parts car I was tearing down. Exhaust was also tucked in the tunnel and PO had put to spacers under the plate to clear the pypes exhaust system. Does not show all but you can see partial.
David

[Hemikiller]

Do you plan on racing this car? Seems extreme if it's just a cruiser

I had the same thoughts. Unless you plan on thrashing this car weekly on the strip, it's really not needed.

[Stanglover]

I just do regular inspections of the U joints at least once a season along with a good general once over. Not to say the U joints won't break at some point, but at least I checked for wear and tear. My car usually does about 1500 miles a season, but I do on occasion drive her hard.

[Jeff73Mach1]

If you ever do burnouts or hard launches without a safety loop, you are taking a risk. With stock street tires and power levels the risk is low, with sticky tires and an extra 100 horsepower over factory, and a stock driveline the risk is very real. Since building to the 4-500 horsepower level is pretty common these days I encourage people to upgrade yokes and U joints and use a safety loop. If you just cruise nice and refined like and you don't want to be bothered, then don't

[87fox72mach]

I think k put heavy duty u joints on mine. I don't launch it or usually do burnouts but I get on it once and a while. It's an interesting read to hear people's horror stories

[Jeff73Mach1]

I sheared my front u joint and had a safety loop-it banged the hell out of stuff. I now have chrome moly yokes on both ends and 1350 u joints on a 3.5 driveshaft and stronger safety loop on both ends- check this out



It is all chrome moly steel and welded up by a very talented welder. It was so pretty I clear coated it to show off his work.

[digithead]

I can tell you it will shake your teeth out if it does break or come loose. I was going down the interstate doing about 65 mph in my 1950 Ford in about 1970. I heard something hit the floor board and then all H%&& broke loose. One of the retainer clips on the front U joint came out and then the cap came out so there is like 1/4" play in the joint. It flopped around and then came apart. The emergency brake cables were the only thing that saved me. The driveshaft flopping around under there broke the cast iron tail shaft on the 3 speed transmission. It shook the car so hard it popped the hood latch but safe catch caught it. It blurred my vision it shook the car so violently.
The plate your mechanic is talking about is pretty beefy, 3/16" thick maybe with 6 I believe 5/16" bolts holding it up to the floor. It would sure help.
In the 60's before they required the safety loop on race cars a friend of mine flipped his car end over end three times and he woke up in the hospital. Front came loose and shaft stuck in asphalt and pole vaulted the car into the air probably doing 80 mph on a circle track.
I am putting a loop on my 72 Q vert along with a 6 point roll bar since I will be on road coarse and drag strip with it. Will also have a scatter shield over the flex plate torque converter. I have seen flywheels come through the floor, dash and out the windshield. Also cut the steering column and headers into. He was lucky did not loose a leg or foot. It was a new bone stock 289 K code at the Asheville drag strip.
If you ever have one come loose or break you will remember it.
The pictures are of a parts car I was tearing down. Exhaust was also tucked in the tunnel and PO had put to spacers under the plate to clear the pypes exhaust system. Does not show all but you can see partial.
David

Thank you! Awesome pixs thats just what I was hoping for. Now tell me you have your own lift in your garage! Thats my next big purchase, except I have to build a new garage to house the new lift. This car is getting expensive.