I was under the impression that using a 12 point was better due to it fitting snugger on the wrench then using my 6 point on there ....

hmm

 

Look inside the socket/wrench. See how much surface there is to contact the bolt head face? Then look at a 6 point. After you wrench every day for 10 years your learn your lesson on 12 pointers.

 

I think he is trying to say that the bolts are 12 point, and he is right, many driveshafts are that way.



You must use a 12 point socket on those, because a 6 point won't work.

Whether you replace them with hex heads is debatable. I would only use an OEM bolt there, but that is JMO. A 12 point box end on a 12 point bolt head is very strong. They use them on drive shafts so that smaller head bolts can be used where there is limited space.

 

only reason I would use a 6 point bolt is because you can force more leverage on them with a cheater bar than you can on a 12 point. The odds of a six point wrench slipping are far less than a twelve point. 12 points have a tendancy to round off easier than a 6, even with a twelve point socket or wrench, GENERALLY SPEAKING.

If you use hex heads you give yourself more surface contact for the wrench/socket to contact upon. This will allow more torque to be transfered to the head of the bolt. A 12 point head has less surface area since there are more corners and by having more corners, there is less surface area for the socket/wrench to engage. With less surface area you increase the chances of rounding off the head (I really really hate it when that happens) so stick with a hex head.
Its also worth noting that the really really important bolts, i.e. the bolt that holds the drive belt gear to the crank snout that requires 150 ft.lb. of torque is a hex bolt. Most engine fasteners are hex bolts. Why? Engineers say they're better for the same reason as above.

 

There is an engineering reason for using a 12 point bolt in that application. If you look at that picture of the Ford bolt you might figure it out. But I don't think we should clutter up the OP's thread discussing bolts and wrenches.

 

I see hex head bolts in the pictures. Not cluttering; it's pretty good info for most people in here.

 

I was speaking of this photo, Brent -


I'm pretty sure that is what the OP has on his drive line pinion flange. It's the Ford way.

Look at the size of the head compared to the size of the bolt. It is a smaller head, and that is because there is very limited space around the universal joint. You cannot get a full sized head in there, so they use an undersized head, and make it 12 point so you can turn 1/12 of a turn at a time. If you replace that with a full sized hex head, I don't think you can get a box end wrench on the head.

They didn't make it 12 point just to **** us off, there was a good reason for it.

Some cars will use an allen socket head there because of the space limitation. I think this Ford way is better.

 

yeah I see what you guys are saying, lastnight while trying to force it, I started to feel it round off so i backed away in hopes that letting it soak overnight will help !

 

One thing I think we all agree on, is to use a 6 point wrench or socket anytime you can.

 

In my experience, a good, undamaged 12-pt set will get it done as long as you're SURE you're using the right size... many problems arise when somebody uses a 9/16" instead of a 14mm or something similar...

as time goes on, the 12pts will wear out and begin to lose their bite on 6 point bolts simply due to slack in the teeth.

12-pt bolt heads are stronger, that's why you can use a smaller head for the same torque. When you use a smaller head, each corner has to be able to take more force...but there are twice as many corners to spread the load over. 6 points round out because you exert too much force on the area the wrench bites. A 6-pt wrench will get you a little bit more force than a snug 12-pt before it rounds the bolt off, but the only advantage is the support midway between the corners... this area doesn't put any torque on the bolt itself.

The effectiveness of a wrench is really a ratio of the size of the bolt head to the distance force is applied. You wouldn't want a 1" wrench that was only 3" long, would you? But a 3" long wrench for a 1/4" bolt head is plenty. All of the force multiplied by the distance you apply it at divided by half of the wrench size goes into those 4, 6, or 12 corners... at some point...they just shear.

 

No, 12 point sockets/wrenches won't "get it done" just as good.

 

I'm familiar with those and they have been using them about 30 years and naturally you would want to use a 12 pt wrench on it.

 

The torch would probably be the way to go, along with several licks from a hammer to break the seal. Don't forget to put some anti-seize on the threads when you put it back together. This just goes to show not to under estimate the potential of damage due to a u-joint going bad. I dropped a shaft a few years ago, but thankfully no damage, it did happen on the expressway during rush hour of course.

 

hmm...okay

 

Well guys ... after some hard work, help (from you guys of course), determination, and the willingness to break it ... I finally got everything off and ready tomorrow to strip the TC apart and figure out why oh why the damn thing keeps popping into N ...

At the end of the day, it took me about 45 mins (20 of which to construct a special tool) which allowed me to get more leverage in those tight areas and the other 25 just undoing those 6 bolts ! none of which broke by the way !!! and I believe only 1 rounded off a bit!

here is the damaged piece I was trying to explain to everyone earlier how it was cracked ...