cross threaded -
LinkBack Thread Tools
post #1 of 10 Old 07-01-2018, 04:45 PM Thread Starter
Registered User
Join Date: Sep 2016
Posts: 6
cross threaded

So the bolt holes into the rear diff for the ball joint are cross threaded (2 of them)....i did not do this and i do not trust the shop it did to fix it. Would the best fix be helicoil or insert? none come in that depth, i assume tapping to a larger size wouldnt be a good idea.

krisnp is offline  
Sponsored Links
post #2 of 10 Old 07-01-2018, 06:27 PM
Registered User
2002 WJ 
Join Date: Nov 2016
Location: Madrid, NY
Posts: 942
What type of insert? Only kind of threaded insert I can think of is a nutsert and those are only for sheet metal

I'd go for a helicoil. First site I came to said that's a 5/16" fastener. Minimum thread engagement of most fasteners is between 1 and 1 1/2 times the bolt diameter(depends on who you ask. So between 5/16 and 13/32( 0.3125" to 0.46875"). Size I'm seeing for the basic Helicoil in 5/16-18 is 0.47 long so just above the minimum length for full bolt strength. Helicoils can also be found in other lengths.

Edit: Opps, misread and thought you were talking about the diff cover bolts. Upper Balljoint bolts are supposed to be M14x2x36. Helicoil length is 21mm for those from what I've seen. An M14 fastener is nominally 14mm across so 21mm is exactly 1.5x that so by the book, it gives enough thread engagement for the full strength of the fastener.

Project Thumper:

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Member of Fourth Coast Jeeps
Ravenbar is offline  
post #3 of 10 Old 07-01-2018, 08:12 PM
Registered User
4WDlifeform's Avatar
2004 WJ 
Join Date: Oct 2009
Location: Pittsburgh, PA
Posts: 674
Are you sure the bolts are actually cross-threaded?? That would be quite a fight running those bolts that far down cross threaded... and not bust or round off the head. But, I guess I've seen crazyer things..! Before you get into it that far, just make sure the threads are actually damaged. Those bolts are installed with thread locker and can fight pretty hard coming out, possibly making you think they are x-threaded.

Helicoils work by drilling to a larger size anyway, so why not just throw M16 bolts in there? I guess you'd have to check bolt head clearance against the ball joint. If I recall, that is already pretty tight in there. You should have plenty of meat in that casting to drill out though. Either method should work fine. Good luck!

'04 WJ 4.0, 335k miles, 2" Coils, 255/70 KO2s, Aussie rear, hydra front, 4.10s, 2x6 tube sliders
4WDlifeform is offline  
post #4 of 10 Old 05-13-2021, 11:42 PM
Registered User
Bigcat2728's Avatar
Join Date: Jan 2019
Location: El Cajon
Posts: 7
What was the final verdict on this repair? I only ask because I myself am in a similar situation, I have one bolt broken off in the housing and another stripped. I was thinking about the coil but know the axle housing is aluminum and was worried the fix wouldn’t be permanent and was curious of your results. Thanks

I barely touched it!
Bigcat2728 is offline  
post #5 of 10 Old 05-14-2021, 05:34 AM
Registered User
mak_v8's Avatar
2002 WJ 
Join Date: Oct 2016
Location: Milan, Italy
Posts: 361
I think that helicoil is the only way; I don't know exactly, but probably the hole must be enlarged in different sizes if you have to use them in steel or aluminium

I don't see other solutions

Grand Cherokee WJ 4.7 V8 HO. m.y. 2002
mak_v8 is offline  
post #6 of 10 Old 05-14-2021, 06:43 AM
Registered User
2004 WJ 
Join Date: May 2020
Location: Aroostook County
Posts: 196
I wouldn't think twice about tapping aluminum to a bigger size. It's fairly common for steel bolts to seize inside aluminum and the threads get ruined no matter what you do. I have not had to do this so I don't know for sure how much meat is in there.
snowbuggy is online now  
post #7 of 10 Old 05-14-2021, 09:25 AM
Registered User
Bigcat2728's Avatar
Join Date: Jan 2019
Location: El Cajon
Posts: 7
Yeah, the only other solution I see is a new rear end, but obviously I’d rather get some larger bolts and re-tap the diff and keep my fingers crossed that everything holds this time.

I barely touched it!
Bigcat2728 is offline  
post #8 of 10 Old 05-14-2021, 09:34 AM
Registered User
2000 WJ 
Join Date: Dec 2016
Location: Kelowna
Posts: 2,552
I've put helicoils and solid inserts (I can't recall the name, Timesert maybe?) into aluminum heads with no issues. Though I don't think there's much difference in doing that vs just going to a larger bolt.

00 WJ
[x] 07 WK CRD/OME/MALONE 1.5 [x] 00 XJ/OME [x] 97 TJ [x] 92 YJ
underscore is offline  
post #9 of 10 Old 05-14-2021, 10:11 AM
Registered User
222Doc's Avatar
2012 JK Wrangler 
Join Date: Sep 2011
Location: Lake Havasu City
Posts: 10,061
i have used heli coils to repair alloy head when the studs pull for the rockers. Those dont go into deep as well and still hold well. Longs as the bigger bolt can be accessed and the bracket hole is or drilled for the larger. Might fit depend on play there.

Home of the Parker Desert Splash

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
222Doc is online now  
post #10 of 10 Old 05-14-2021, 08:00 PM
Chris Radley
Registered User
Join Date: Aug 2018
Posts: 43
If my memory serves me, that is a M14-2.0 course thread flange bolt. Grade 8.8 or better.

I would buy a tap M14-2.0 and retap the two bad holes. The original bolts are 35mm long (1.380 inches) and the rear diff holes are actually deeper that that so you could tap deeper if they aren’t already.
Chris Radley is offline  

Quick Reply

Register Now

In order to be able to post messages on the forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.

Email Address:


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome