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Size of bolts that hold the hub on?

D

DerMeister

NAXJA Forum User
Location
MI
Anyone know the size of the 12 point bolts that hold the hub onto a Dana 30? Three on each side.

I have to get my U-joints done, and those bolts are rusted to hell.

Thanks!
 
Nope. Nobody around here ever had to take those out. :D

12 pt 13mm. Welcome to the Rust Belt. I can almost guarantee that those unit bearing hubs are rusted right into place. You're not replacing the hubs, don't use a slide hammer on the wheel studs. You'll hammer right through the rolling elements of the bearing. After you get the bolts spun out a few turns, say 1/4" to 1/2", brace a socket & extension against the inner C of the axle, and use the power steering to pop it loose. It'll probably take 2 of you, and be careful, it won't take much from the p/s to get it loose. You don't want to pop it loose and then continue to press against it. Oh, and keep the far side on the ground to provide a little more resistance.

And if you haven't done it yet, take the wheels off on both sides, and start hosing the seam between the hub and knuckle with rust penetrant.
 
If you need to chase the threads in the unit bearing flange (you probably do) they are an M12x1.75 thread. Not sure if your local HW store will have that size, but mine did.

if the damn thing rounds off, try hammering a 12mm 12 point onto it, if that doesn't work, use a dremel to grind all the rust off the head and flange and then weld a 5/8" thread hex nut on and go to town with a breaker bar. Did that last time I rounded one off and it worked out pretty well, the heat broke the rust bond and the bolt spun out with only a ratchet after I broke it free.
 
Something else to consider, start hosing down the u-joint caps with rust penetrant as well. Be careful to not bend the yoke ears when removing or replacing the caps.
 
Best method for doing U-joints:
 
When re-assembling, clean the rust off the mating surfaces of the bearing and knuckle with some heavy grit sandpaper, use a liberal coating of anti-sieze on the bolt threads AND on the mating surface between the unit bearing and the knuckle... that way when you have to take it apart again, it won't be such a bear of a job.
 
Pic of OEM bolt with data.

boltknuckletohub-001.jpg


mod note: replaced image with one without substitute bolt information included.
 
Last edited by a moderator:
*INTERESTING*. I've always looked at that as a specialized bolt due to the somewhat pronounced shoulder area under the flange. Apparently not.... the Fastenal SKU is still live, and shows a wholesale price of 4.28/ea. I suspect that the Fastenal bolt is actually a 6 point head, not a 12 point. It is listed as a 16mm wrench, 75 ft./lbs. might not be too difficult to keep square. I would not consider anything less than a 10.9 hardness, though, regardless of manufacturer or style.
 
I thought the torque spec was 125 on those bolts - not that I've ever actually torqued them, I use the gudentight spec on those since my torque wrench probably wouldn't fit into the space over the upper one anyways.

edit: I am wrong, this is not the post you are looking for, move along now
 
Last edited:
kastein said:
I thought the torque spec was 125 on those bolts - not that I've ever actually torqued them, I use the gudentight spec on those since my torque wrench probably wouldn't fit into the space over the upper one anyways.
Click to expand...

It is 75 ft. lbs.

I had no problem torquing mine and I have a large torque wrench. You just have to turn the steering knuckle in a suitable direction.
 
Last edited:
ChiXJeff said:
*INTERESTING*. I've always looked at that as a specialized bolt due to the somewhat pronounced shoulder area under the flange. Apparently not.... the Fastenal SKU is still live, and shows a wholesale price of 4.28/ea. I suspect that the Fastenal bolt is actually a 6 point head, not a 12 point. It is listed as a 16mm wrench, 75 ft./lbs. might not be too difficult to keep square. I would not consider anything less than a 10.9 hardness, though, regardless of manufacturer or style.
Click to expand...

I added that substitute bolt data. Use at your own risk.
 
36 mm axle shaft nut is 175 ft/lbs torque.

13mm 12 point unit hub bolts are 75 ft/lbs torque. Failure to use correct torque can shorten the unit hub service life.
 
I stand corrected!
 
Actually I posted the wrong image from my photobucket. The one I normally post doesn't have that substitute data on it.

I created the image using Microsoft Office Visio. I bought a complete set of new OEM bolts from the dealer when I did my hubs, and scanned one before installing it.

Here's the proper image, if the Mods want to delete that previous one.

boltknuckletohub-001.jpg
 
I substituted the one you just posted and left a note to avoid confusion :thumbup:
 
Thanks guys!

The dealership wanted $6 a piece for these.

I called fastenal which is only 20 minutes away, and I had him order 6 of them for $2.68 a piece and they are 10.9 grade. Should have them monday morning. I'll probably use some grade 8 thick washers I have, since they aren't flange heads.

Also got NAPA precision U-joints. Got the greaseable ones, the best ones they had.

Thanks for the bolt size, torque specs, and other methods to help the job be easier guys.
 
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