Half Shaft Bolts

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Old Thread on Half Shaft Bolts

Thanks much!

Does anyone have the torque spec?

usmcfred

from the shop manual

50 FT-Lbs

JFB beat me to it by 3 minutes ;-) however it is tricky to tighten them with a torque Wrench, it is usually easier with a Spanner. Hope you have the feel for 50 ft-Lbs

Thanks again.

usmcfred

I've run into a peculiar situation twice with stock halfshaft bolts. Specifically, the halfshaft bolt split-lock washers fail. On two cars whose owners complained of vibration under acceleration, I found (1)- a loose (or less-than 50 ft-lbs torque) bolt. Tightened and the vibration went away. The second had a missing split-lock washer which broke, then fell out, so one bolt was little more than hand-tight. Again, tightening the bolt 'to feel' (without a torque wrench or washer 'cause we were on the road) fixed the vibration. I stopped using OEM split-locks here.

There are 16 bolts & nuts in the two halfshaft assemblies, and with these two cars st least, only one bolt was looser than the rest & apparently still caused noticable vibration under power.

The same halfshaft bolts can be oriented either with hex-heads inboard or outboard of the flanges. Bolt-heads inboard requires playing with the flange positions to work the bolts into the holes, but once installed they're simple to torque. With the bolts oriented inboard (the 'easy' way), you have to either 'torque-to-feel' or torque the bolt head, not the nut. A 3rd way is to tighten each nut using a crows-foot socket in a torque wrench. Joint torque is likely to be a little different than spec. with method 2 & 3.

Finally, the 16 bolts MUST be unthreaded-shank 11 mm gr-5-equivalent bolts (early cars) or unthreaded-shank SAE 5/8" gr-5 bolts on later ones, with elastic lock-nuts. Ford apparently changed the bolts & nuts at some point during full production. Threaded shanks will pound in due to the thread's greater clearance in the flange holes, and again, there will be vibration. A really touchy area!

I believe the Bolts are 7/16 UNF and not 5/8? I agree that split Washers has no business there.

So, the 16 OEM split washers should be ELIMINATED and only the correct AN bolts and elastic stop nuts used? usmcfred

Split washers are just looking for trouble and should be avoided. Especially since these Bolt are supposed to be torqued with 50ft-Lbs and using self locking Nuts (nylock). Split Washers are more like for Farm Machinery etc. If you tighten a Nut on top of one hard enough the Split Washer can split/open and fail.

I second all bosswrench remarks... Shanked, No lock washers, installed from inboard side with nuts on outboard. I use new nyloc nuts. In this application I don't really like ARP fasteners, as I don't think there is enough bolt length to permit elastic stretch.

Something to verify before removing the washer is to ensure the threads don't extend past the flange. you want a couple threads after torquing in the clamped joints.

quote:

Originally posted by Bosswrench:
...the 16 bolts MUST be unthreaded-shank 11 mm
or unthreaded-shank SAE 5/8" gr-5 bolts on later ones.

I took thicknes measurements on by axle flange, and half shaft flanges. (I don't have the ZF flange)

the axle flange was ~0.32"
one end half shaft ~0.23"
thus total thicknes of 0.55"

for an untread shank of 11mm (0.43") removing the split washer would be OK
for an untreated shank of 5/8 (0.63) the split washers thicknes of ~0.1" is needed (still too close for me)
the linked thread recomend AN7-11, which has untreaded shank of 9/16 (0.56") and a split washer is also needed.

something I didn't expect to find was that for the one half shaft I dugout to measure, the two end flanges were differnt thickness. One was ~0.23 and the other 0.35". sure wish I knew the ZF flange thickness.

AND, I had an assortment of untreaded shank and full thread bolts with washers.

edit
I look again and determined the yoke flange that bolted to the axle was the thicker, thus for my axle flange

Thank you.

So, will AN-7/11A bolts with NO split washer secured with an elastic stop nut work, or should the AN-7/12A bolts be used?

Alternatively, can a flat washer be substituted for the split washer and used as a "spacer"?

usmcfred

can you measure your flange thickness to know?

I didn't look closely at my flanges yesterday, but the flat washer may be too large OD and not sit "flat"

I do not mean to confuse nor contradict what the other posters here have stated, but I would want to know how well the bolts fit and not assume “one size fits all”

something else I would ensure is that the hole where the bolt head would be against needs to be champered to account for the 0.010 radius at the transition. I could see the bolt head not going down hard and thus result in bolts "loosen"