Help! Broke Off Rear Wheel Stud

Kid Vette

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Mar 25, 2008
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Santa Cruz, CA
I just broke off one of the rear wheel studs. Is it true it can be replaced without pulling the spindle? Do I need to worry about the bearings while I beat it out? I need 7/16-20 thread x 1 3/4 long, .480 knurl; correct?
 
Yes it can be replaced without removing the spindle. You can drive it out without harm. Stock has .467 knurl s .48s would be a good replacement.
 
If you break one the other 19 are probably not in any better shape.... time for some ARP or Moroso studs in M12, they are available with .480 and .485 knurl. If you run the stock aluminum wheels they have the stock style nuts in M12 which is almost like 1/2" but still better than the 7/16 stud - M12 studs (ARP) are rated at 190000psi, way better than the 30+ year old studs....
I think Corvettesouth sells these nuts. I posted a link for member 69427 not too long ago.... they might have these nuts in 1/2" also....
Tapered seat nuts are available in all sizes....
 
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Just an update. I replaced the wheel stud Saturday. Of course the rotor was rusted on the hub. Took some heat, PB Blaster and a couple whacks to get it off. :banghead: Had to bend the dust shield a bit to put the new stud in. Used a lug nut to draw the stud in. Pulled in so far then stopped. I tapped it back out to see that I was pushing a heck of a burr up on the knurl. :amazed: Filed off the burr and tried again - same thing happened. I ended up filing almost all the knurl off and it finally seated, still very tight.

Of course by this time the emergency brake springs had somehow fallen off. :cussing: After a couple feeble attempts to get them back on, I gave up and removed all the emergency brake hardware - I had already done the same thing on the other side a few years back. I'll get them back in comission when I rebuild the TAs.

The good news is my wife showed up just in time to help bleed the caliper and I'm back on the road again. :)
 
Good news...:thumbs:..... what size did you end up using ? Just the stock ones for now ? Are you planning on using stronger better stuff when you rebuild the arms ??
 
Good news...:thumbs:..... what size did you end up using ? Just the stock ones for now ? Are you planning on using stronger better stuff when you rebuild the arms ??

I am thinking of going with 12mm studs only because that is easy to do and parts are universal. Also, I don't really get the fascination with bigger studs, the bearing supports are held on with four 3/8 dia bolts. Looks like if an upgrade is needed, it's needed there.
 
Also, I don't really get the fascination with bigger studs, the bearing supports are held on with four 3/8 dia bolts. Looks like if an upgrade is needed, it's needed there.

The trailing arm actually provides very little support for the bearing housing.

The main function of the trailing arm is to provide centering support ie. front to rear stabilization, not side loading. The large force vectors are at the strut and half shaft. There will be no large momental forces between the trailing arm and bearing housing only fore aft loads ie shear loading. Hell, the t/a is so wimpy it just conformes to whatever camber the wheel is set at. It was intentionally designed this way.

That being said, i still agree with you. I don't see anyone doing this mod using their car for racing.

But it can be very important for people running spacers or wheel adapters, especially those that are not hub centric. Shifting the load out further on the stud puts huge moments on the stud and the worst are impact loads from driving on rough pothole filled roads rather than racing.

I learned this the experimental way when 2 studs snapped when putting about 10 ft pounds of torque on them. I was dangerously close to losing a wheel.

This is one thing that has always ticked me off. Most vetters look at my car and think what a POS deathtrap, many of them people who have slapped a shitty set of 1/2" spacers on to fit a very pretty set of wheels.
 
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Good news...:thumbs:..... what size did you end up using ? Just the stock ones for now ? Are you planning on using stronger better stuff when you rebuild the arms ??
Yes, I just did stock replacement for now. I'll go with larger studs when I do the TAs. I would like to open the holes up in a drill press. I'm lousy at eyeballing perpendicularity with a hand held drill.
 
Also, I don't really get the fascination with bigger studs, the bearing supports are held on with four 3/8 dia bolts. Looks like if an upgrade is needed, it's needed there.

The trailing arm actually provides very little support for the bearing housing.

The main function of the trailing arm is to provide centering support ie. front to rear stabilization, not side loading. The large force vectors are at the strut and half shaft. There will be no large momental forces between the trailing arm and bearing housing only fore aft loads ie shear loading. Hell, the t/a is so wimpy it just conformes to whatever camber the wheel is set at. It was intentionally designed this way.

That being said, i still agree with you. I don't see anyone doing this mod using their car for racing.

But it can be very important for people running spacers or wheel adapters, especially those that are not hub centric. Shifting the load out further on the stud puts huge moments on the stud and the worst are impact loads from driving on rough pothole filled roads rather than racing.

I learned this the experimental way when 2 studs snapped when putting about 10 ft pounds of torque on them. I was dangerously close to losing a wheel.


The four 3/8 bolts I am talking about are 3 inches long and attach the caliper bracket to the trailing arm. When you apply your brakes, these 4 bolts counter the torsional shear from the caliper and, in addition, counter the jounce forces.
 
The four 3/8 bolts I am talking about are 3 inches long and attach the caliper bracket to the trailing arm. When you apply your brakes, these 4 bolts counter the torsional shear from the caliper and, in addition, counter the jounce forces.

exactly. It's all shear load which bolts do very well. It's the tensile loads that snap bolts.
 
The four 3/8 bolts I am talking about are 3 inches long and attach the caliper bracket to the trailing arm. When you apply your brakes, these 4 bolts counter the torsional shear from the caliper and, in addition, counter the jounce forces.

exactly. It's all shear load which bolts do very well. It's the tensile loads that snap bolts.

There is a tensile force on these small bolts from jounce, braking and acceleration. Combined stress is what causes failure.

I think we are both saying the same thing. If these bolts are sufficient, stock wheel studs are more than enough.
 
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