hub bolts

[cfg11]

What causes the bolts on a wide 5 hub to loosen? We have a 8 bolt hub that the bolts that hold the drive plate on keep coming loose after one night. We have tried locktight and it doesn’t seem to help. It’s only loosening on the RR. Does this mean there is a problem? Or is this common?

[merc123]

I'm guessing you're talking about the drive flange plate. Could it be cracked around some of the bolt holes?

[AmickRacing]

I've heard people have had issues with the 5 bolt drive plates not staying tight, but never heard of that with the 8 bolt.

I'm running the 5 bolt, and just loc-tite them and safety wire them.

[restad4r]

Not sure if it's common on other peoples car but mine come loose sometimes just use red loctite and safety wire them.

[powerslide]

Like previously mentioned safety wire. It's common

[lovinlatemodels]

Try cleaning the bolts and hubs threads real good then just use silcon on them and tighten them up did this yrs ago never came loose again.

[FlatTire]

The reason these drive flanges comes loose is because the bolted joint connection is not designed to the correct L/D ratio. L is the thickness
of the clamped material. D is the diameter of the bolt.

When you design a bolted joint connection you try and achieve a 4:1 ratio between the bolt diameter and the material that is clamped.

In this case, the bolts are 7/16"/.4375" and the clamped section which is the thickness of the drive flange is .38". So this gives you an
L/D ratio of .38/.4375 = .85 which is too low to ensure sufficient clamp load.

Basically, the thicker the clamped section, the more elastic deformation you have to dampen high cycle vibrations.

I used to run the old 8 bolt flanges and always torqued them down and never had a problem.

When I switched to the newer 5bolt flanges I torqued them with the same torque I torqued my 8 bolt flanges and they would not stay tight. I finally started increasing the
torque until they quit backing off.

No matter if you run 5 or 8 bolt flangs, if you torque them down sufficiently, you CAN keep them tight. I still check mine with the torque wrench every 4 races just to make sure.

I'll check in my tool box and look up the exact torque value I've been using and post it here.

[Matt49]

The good people at Wilwood told me 42 foot pounds and always safety wire. If you safety wire PROPERLY they will never come loose.

[48bad]

A bent axle housing will cause the bolts to loosen.

[cfg11]

The side bell? or a bent tube? can make them loose?

[48bad]

The axle tube.

[TALON75]

if they are a bit old you might want to try new lock washers, one of our cars had them flattened out so much(and some wear on the flange) and the bolt would bottom out before it was actually tight on the flange . just something else to check .

[speaker56]

95% of the time it is the bell that is out of wack NOT the tube. Had a problem with our rearend at beginning of the season and after talking to Winters, Mars, and several other people they all said rarely does the tube itself bend.

[FlatTire]

I torque my 8 bolt flanges at 60ft-lbs and my 5 bolt flanges at 75 ft-lbs and don't use any safety wire. I don't have any stripping issues and they don't come loose.
I do put a little anti-seize on the threads.

I don't use lock washers either. I've seen testing done by a nationally known fastener expert and the video showed that lock washers are pretty much worthless at keeping
a bolt/nut tight. I work for a major machinery builder and we don't use them anywhere on our equipment.

[48bad]

I agree with Flattire on all accounts. They should stay tight with the proper torque unless there is a problem. We,too, quit using lock washers years ago. They are pretty much useless. To speaker56, how did your bell get "out of wack" without bending an axle tube? Did Winters tell you if you make contact, 95% of the time it deforms the bell and only 5% of the time it bends the axle tube?