I was taking out my Diff today to get gears installed. When it came time to disconnect the Driveshaft from the Diff, I got queezy, cause i HATE hex key bolts, especially when they're tight. Well, my worst nightmare came true, and i stripped them.

The Solution:

I took my Dremel (love this thing) and sawed off the heads of the bolts. When i got off all of the other bolts to the diff, and started to take it out, they slipped right through, wil no problems. When i had the Diff sitting on the ground, i went to take the bolts with no heads out, and i could unscrew them with my fingers with ease. I don't understand how they get so tight, but i'm glad i fixed it....this whole process with separating the driveshaft always gives me a headache.

Just wanted to share my experience, in case someone runs into the same problem.

 

The common method is to use a cold chisel and knock the heads with glancing blows to get them rotating. You use the chisel tangentially to the head digging into the material about 1/8 inch.

You will need to use new fasteners once you get them apart.

If you have room you can also drill down through the heads so the heads fall off. Once its apart you can then get the shafts out with pliers.

Chris.

 

agree with the above
factories tend to overtorque these in to be sure they dont come loose, over time rust on the threads will finish off the job
also a light tap with the hammer and a bit of heat + penetrating oil on the other end can help too as well as un - torqing them fast and hard to break them loose initially as gradually increasing the force may lead to stripping the head
you need to have really good allen keys that are a tight fit to get the best grip
black hardened ones that fit to a 1/2 in socket are best
when you re fit dont do them up over tight and use blue loctite to make sure they will not self undo, the loctite will also stop them corroding in place
hope this helps
Paul

 

They are pretty soft and very tight. I stripped a couple off mine before I learnt what to do. A nice hex head socket on a long breaker bar and give them a quick sharp turn. The rest (10, I was doing both ends) came off fine. Replacements cost me $USD8 each.

 

yes, a 6mm hex socket is the way to properly get them off. if you strip them you can use vice grips to get them off too.

 

This has been discussed a bit in the past. Many of us have the theory that these bolts are not over-tightened at all. They are hard to get off due to some sort of "Galvanic" corrosion/adhesion. This is when the underside of the bolt head adheres to its mating surface next to it. This is the reason why these sorts of bolts must be "snapped" loose with a sudden, forcefull motion. A slow gradual turn only damages the head.
As you already discovered, it is also not due to rust forming on the threads, since you were able to remove the broken end with your fingers.
Another good example of this adhesion are the bolts that hold your spark plug cover onto the valve cover. Even if you put those bolts on with only moderate pressure, if you go back a few weeks later, you will find that they seem "stuck". And it is with that initial "snap" that the bolts come free.
When I did my rear diff, I made sure all those bolts were "snapped". Never lost a single one.

 

I also used PB Blaster. Everyone says that it's great stuff, but it didn't work in this case ( I even let it sit overnight).

 

Stuff like this and WD-40 and Liquid Wrench penetrate into threads to loosen things up. In this case, it is not the threads that are seized. These sorts of penetrants will not get into Galvanic corrosion.

 

So quick snapping is the only way?

 

Well, I've found it to be the best way. You have to make sure that the tool (hex wrench or socket) is the exact size for the bolt head and make sure that the tool is fully and squarely seated in or over the head before snapping.