What Kind Of Bolts Are On The Drive Shaft Yoke?

[mlochala]

Today, I attempted to replace the pinion seal on the rear differential of my '98 Merc'aneer AWD. I say attempted because all efforts failed at getting the bolts loose on the rear u-joint.

The nuts appear to be about 13-14mm in diameter but are similar in shape to a torque/star style bolt. They had more ridges than a typical star bolt, and as luck would have it, I did not have an internal torque star socket of that size. I was told a 12-point socket of similar size would work so I tried that instead.

A couple of hours and one can of PB Blaster later, and the bolts haven't budged a hair. Like any good mechanic wannabe, I rounded off one of the bolts with a pair of vise grips just for spite.

Any ideas or suggestions on what to use or how to get these off?

I assure you they will be replaced with a conventional bolt when they do come off.

 

[Foxracin]

There 12 point 12mm.

 

[BrooklynBay]

Use this tool: http://www.explorerforum.com/reviewpost/showproduct.php/product/458/cat/all

 

[drdoom]

There 12 point 12mm.

Ya, I used a 12mm combo wrench, and a piece of pipe.

 

[FarmTruk]

lefty loosey. righty tighty.




seriously though, sometimes actually "tightening" a stuck bolt can free it up just enough to get it moving. At that point, start backing it out.


A blowtorch can get some heat on the sucker, too. Heat is your friend v. rusted bolts.


Penetrating oils, such as the PB Blaster you mentioned, can work wonders, too. Just keep applying it, over a few days, allowing it to wick in to the threads.

 

[mlochala]

Thanks for the replies!

Any suggestions on removing the now rounded bolt? Do those nut remover kits (for about $23) work?

As a last resort, I may weld a new nut to the remaining part of the bolt head and try it again.

One last question on this subject, what is the bolt size (length, diameter, and thread) for a replacement? And, what grade do you recommend? Grade 8?

 

[OneLever]

Buy an external Torx socket that fits it. Then use PB Blaster, a torch, then the socket on a breaker bar. Regular sockets will just round off as you now know.

Got a picture of the rounded head? Depending on how rounded it is an extractor might work. But welding on a nut is always an option.

 

[Brandon96]

If no welder, another option for the rounded bolt..

If you've never taken the driveshaft off before it could have a bunch of thread locker on the bolts, I know mine did when I disassembled it for the first time. Like suggested, you could try torching the head/backside of the bolt and then hitting it with water a few times to try and break up the thread locker/weaken the bolt, then try to back it out with your vise grips. Who knows, you might even end up snapping the bolt head off, In that case you could get the rest out easy a pie.

 

[OneLever]

you might even end up snapping the bolt head off, In that case you could get the rest out easy a pie.

While I can honestly say that's not the first thing that passes through my mind when I snap a bolt head off. It is certainly a good attitude to have.

 

[Brandon96]

While I can honestly say that's not the first thing that passes through my mind when I snap a bolt head off. It is certainly a good attitude to have.

Lol, I do it all the time now!

If you snap a bolt head off I'm assuming you have at least 1/2" if not more of the threaded section left. If so, grab a 1/2" or 3/4" chuck off a power drill/drill press etc.. and tighten that baby down as hard as possible on the rest of the threads. Then you've really got something to grab a hold of, whether it be with a ratchet fitting to insert into the back of the chuck, or a pipe wrench to really get some torque on that bolt.

My track record is holding up so far! It's been like Brandon - 6, broken/stripped bolts - 0

 

[OneLever]

Side note to the original poster: You're doing this with the wheels on the ground not jacked up right? I'd be careful to check for stability and put redundant items under the axle if it was jacked up.

 

[Baddecision93]

I literally just did this last night, detached the driveshaft from the axle.

I'm not afraid to admit it took me like 20 minutes to figure out how to get the bolts out. The Haynes manual just says "remove bolts". Thanks, lol.

One suggestion, put jack stands under each side of the axle and you should be able to then, with the tires off, push up and rotate the driveshaft easily (if not you will find a bolt or two difficult to get to). Also break all the bolts VERY lose before you take any one completely out. Otherwise you have the binding/driveshaft is spinning as you take one bolt out problem that I had last night.

Good luck.

P.S. Never used them on my EX but extractor sockets work wonders.