Cross threaded a Diff Cover Bolt

[Boaring1961]

Today when changing and putting the cover back on my front diff the bolts didn't want to spin on by hand. On a couple of them I had no choice but to start them with the socket. One of them is now cross threaded and goes in about halfway before it get's so tight that I feel like it's going to shear off.



For a temp fix I put two thick washers behind the head of the bolt so it will at least seat against the cover and not leak. Would this be fine for long term or should I fix it? What's the best route in fixing this?



Thanks

 

[BLNRAY]

Pull the bolt,run a tap in the hole,put a new bolt in. Or if its not leaking like it is,leave it alone

 

[RVTRKN]

Remove the bolt and inspect the threads in the case to see how much damage there is to the threads. Get the tap size needed, and carefully try to restore the threads being careful not to tap the threads that are crossed. Get a new bolt and use the proper Locktite and slowly, and by hand start the bolt making sure it stays strait as you turn it, catch the correct threads. You may have to do this several times before you get the results you were hoping for. If it starts correctly, then be careful when torquing it down and cross your fingers it holds.

 

[Motorhead]

To prevent this in the future, run a tap into the threads before replacing the bolts on the ones that were stiff to get out.

 

[ata]

Don't use a regular tape. (one with a pointed nose) Get a Thread Chasing Tap it has a flat nose and is a lot easier to start square in the hole.

 

[Wingate]

I would add to this that if these r the factory bolts, be careful not to overtorque as they have a tendenacy to break.

 

[Motorhead]

Don't use a regular tape. (one with a pointed nose) Get a Thread Chasing Tap it has a flat nose and is a lot easier to start square in the hole.

The type you are talking about is called a "bottoming tap"

 

[RVTRKN]

The dealer serviced my diffs so I'm not aware of the casting, do the bolt holes go through the casting or does it have a bottom to them? The reason I ask is, if you tap it and it goes all the way through your going to have shavings fall through.

 

[blacksheepdiesel]

No, the holes do not go into the oil cavity.

Godspeed,
Trent

 

[BIGNASTY]

don't use a regular tape. (one with a pointed nose) get a thread chasing tap it has a flat nose and is a lot easier to start square in the hole.

... ... ... thats what we called them thread chasers

 

[sag2]

The other fix is to thread a short stud into the hole with red lock-tite. Then use a nut on that one and it should last forever.

 

[Gary - K7GLD]

I suspect the primary reason for several bolts not wanting to thread in easily, is either dirty bolt/hole threads, or more likely, the cover not being properly centered, causing the bolts to get cocked to one side when truing to install them - the future method would be to at first, spin ALL the bolts in loosely to be sure the cover IS properly located, THEN tighten them down. And, of course, make sure the bolt and hole threads are properly cleaned...

"WHY do I never have time to do the job RIGHT the first time - but I always find the time to do it OVER again... ?"