Full Floater Hub Stud Upgrade write up (1 Viewer)

[VETTE60]

OK, so I posted the thread about breaking my ARP hub studs and dowells this week on the Rubicon....twice. Well that pissed me off and I decided to make it better with some fellow mudder suggestions.

Went from 8mm studs to 7/16" x20tpi cap bolts. much bigger ande still plenty of meat on the hub.

 

[VETTE60]

next, drilled the stud holes in the hubs in 2 stages. 5/16" to get the threads out and then 3/8". btw, I would not recommend doing this without a drill press. the hole needs to be precise to be tapped well.

 

[VETTE60]

next, tapped the holes with a 7/16" x 20tpi tap. making sure the tap is very straight when started, and also take it in small chunks back and forth using cutting oil. if you take too much you risk chunking some of the threads. and a test fit reveals a nice snug fit without any play.

 

[VETTE60]

next, drilled the holes in the axle shaft out to 7/16". this leaves a small amount of taper at the top from the cones, but not much. I was a bit worried that without a cone there would be some play, but not the case. It is kid of a PITA to drill these on the press, but not too bad. also remembered to drill my spare set of axles in my tool drawer. (that coulda been lame with a busted axle on the trail and holes too small on the spare...)

now...I am not sure about the warranty with the polly's being drilled, but I doubt I woulkd break them there.

 

[VETTE60]

new bearings, and seals, slam it back together, set the wheel bearing preload, torqued the new cap bolts to 65 ft lbs. and there it is!
I used hardened split washers also and had to grind off the small edges that hung over the hub just a bit..

I will keep you updated as to how this works. It seems to me that it will be bomb proof....and now I probably made my pinion the weak link...lol

This came from a fix guys were doing for the front hub, but I have not had that issue yet. Longfield is offering a 4 dowell addition for the front hub that I may go with. well see

time to wheel it and see...

If I break this, I will be going 14 bolt like Drew...

 

[chicago]

Great write up Chris!
Awesome job.
THAT seems like something I might like to take to a machine shop to have done.
Might have to look into getting a FF rear.

 

[GLTHFJ60]

Looks fantastic! I need to do this as well.

 

[Mace]

Might have to look into getting a FF rear.

Save your pennies for a stronger axle.

 

[Cruiserdrew]

Save your pennies for a stronger axle.

Yep-Chicago what are you thinking? You got a fresh build, do a 14 bolt if you have kids in college like me, or a D60/D70 with upgrades if you're living large.

 

[mookie]

that looks real good, but i'd go ahead and put in a hardened dowel between every bolt while your at it

 

[VETTE60]

that looks real good, but i'd go ahead and put in a hardened dowel between every bolt while your at it

you can only add 2 more dowels with the polly's since they have 2 offset extraxctor holes drilled in the flanges, although I am not sure why since they slide right out...

 

[Mace]

you can only add 2 more dowels with the polly's since they have 2 offset extraxctor holes drilled in the flanges, although I am not sure why since they slide right out...

until they bend (not that they will, but it is awfully nice to have the extractor holes there just in case)

 

[Sputnik40]

Not that it's the same - but it was a PITA to get out a bent SF Poly once it was bent - but it was really a matter of coaxing out the c-clip - once that was out a BFH worked nicely.

I'm a huge fan of upgraded dowels, but guess those bolts supercede the dowels by size and number.

Curious - what material/rating were the hex bolts? I could only find stainless for my 14 bolt and am thinking that's a bad choice...

 

[VETTE60]

Not that it's the same - but it was a PITA to get out a bent SF Poly once it was bent - but it was really a matter of coaxing out the c-clip - once that was out a BFH worked nicely.

I'm a huge fan of upgraded dowels, but guess those bolts supercede the dowels by size and number.

Curious - what material/rating were the hex bolts? I could only find stainless for my 14 bolt and am thinking that's a bad choice...

the bolts are automotive grade. Harder than grade 8. I want to say they are 10.9 and agree that the stainless bolts would not be a good choice. my local hardware store in placerville had a whole case of them. this place has been around for 100 years and seems to be one of those gems that has absolutely friggin' everything.

 

[BC40]

Interesting solution.
A 7/16 shouldered stud would probably be even better. If I ever start having problems shearing studs and dowels, I'll keep this in mind .

 

[Mace]

the bolts are automotive grade. Harder than grade 8. I want to say they are 10.9 and agree that the stainless bolts would not be a good choice. my local hardware store in placerville had a whole case of them. this place has been around for 100 years and seems to be one of those gems that has absolutely friggin' everything.

10.9 is approximately equal to Grade 5 and is a metric designation.
You have a metric 7/16" bolt?

 

[Cruiserdrew]

Not that it really matters, but I thought cap screws were automatically Grade 12 in the SAE system.

 

[Mace]

Not that it really matters, but I thought cap screws were automatically Grade 12 in the SAE system.

Grade 12??? I know of no grade 12..

You mean a socket head? "cap screws" han be a multitude of different head designs (including hex head) and come in a variety of strengths.

 

[Isotel]

Dam Mace, you know your stuff!

isint the Friction of the flange and the hub what creats the strenth in this instance? not the bolts themselfs. (hence the Cone washers)

i would think that if the mating surface is clean and smooth, and the bolts are tourqed properly, you would never have an issue. if you broke the studs (they could have been loose), and they mared the surface when it broke, that could have been why they broke a second time.

Similarly to Hi Steer, I run stock studs, and ensured that the top of the knuckle was nice and flat, i keep them tight, and dont have issues with them

 

[Cruiserdrew]

Grade 12??? I know of no grade 12..

You mean a socket head? "cap screws" han be a multitude of different head designs (including hex head) and come in a variety of strengths.

Typically hex cap screws are higher grade than grade 8. Here is an exerpt from Wiki:

Hex cap screws
ASME standard B18.2.1 -1996 specifies Hex Cap Screws that range in size from 0.25–3 in in diameter. These fasteners are very similar to hex bolts. They differ mostly in that they are manufactured to tighter tolerances than the corresponding bolts. The Machinery's Handbook refers parenthetically to these fasteners as "Finished Hex Bolts".[9] Reasonably, these fasteners might be referred to as bolts but based on the US government document, Distinguishing Bolts from Screws, the US government might classify them as screws because of the tighter tolerance.[10] In 1991 responding to an influx of counterfeit fasteners Congress passed PL 101-592[11] "Fastener Quality Act" This resulted in the rewriting of specifications by the ASME B18 committee. B18.2.1 [12] was re-written and as a result they eliminated the "Finished Hex Bolts" and renamed them the "Hex Cap Screw".