Lug Bolts Broke off

[GMAN]

Here is the strangest thing. Three of my lug bolts broke off recently (drivers side), leaving me to just two bolts. I am dumb founded as to why and how this happened. Does anyone have any ideas for me?


Greg

 

[Ishodu]

They may have been over tight or cross threaded. Did this happen while removing them or just on there own? If it did it on there own I would say they were not tight or the wrong nuts.

 

[Mr Anonymous]

Any chance you had someone working on the wheels that used an impact wrench on them?


In any case, while the individual studs are replaceable, I'd recommend replacing the entire hub & bearing since you lost three on the same hub. A bad bearing could also have contributed to the failure.

 

[djsSHO]

Bolts will break also if they aren't tightened enough and the wheel wobbles on the studs. I have seen cars come back with loose lug's and 4 of 5 studs broken. Are the holes in the rim elongated at all? If they are you might consider replacing the rim to be on the safe side.

 

[Shoaz]

Lug nuts that are too loose are more likely to break the studs than nuts that are too tight. Was there any wobbling or vibration?

Sometimes when you replace a wheel and tighten it down, it can re-register itself and you'll wind up with loose nuts. This is why many of the written procedures suggest to tighten the lug nuts and then retighten them after driving it a bit (often the indication is to wait a day or two of driving and then retighten them).

I've had this happen more than once (one time at the end of a track day), where I've tightened down the lug nuts one time after replacing the wheel and they've subsequently worked loose. I'm learning to retighten them or check them after track sessions, although it is a pain.

Replacing the studs is not that difficult. You need to remove the caliper and the brake rotor, turn the hub so that there's clearance in the back, and just tap out the broken stud with a punch and a mallet. Sometimes they need a good whack, and occasionally you'll need a propane torch to heat the hub a little, but generally nothing too tough. If things go well they come out easily.

The new stud can be pulled in with a lug nut put on backwards and a stack of washers.

 

[RCM]

Here is the strangest thing. Three of my lug bolts broke off recently (drivers side), leaving me to just two bolts. I am dumb founded as to why and how this happened. Does anyone have any ideas for me?


Greg

Multiple studs breaking at the same time on the front can be due to incorrect rotor ID (TSB below). Pretty common to see 2-3 broken front studs if an early rotor is used on 1991-95.

Russ
RCM Automotive
http://home.earthlink.net/~rcm_automotive/


TSB 93-22-4

FORD:
1986-93 TAURUS

LINCOLN-MERCURY:
1986-93 SABLE
1988-92 CONTINENTAL

ISSUE:
The misapplication of front brake rotors may result in various front wheel and front brake concerns. The hub pilot hole diameters of front brake rotors, for use on vehicles built on or after 2/1/91 and before 2/1/91, are different. The rotors are NOT interchangeable.

ACTION:
Be certain that the correct front brake rotor is installed. Refer to the Parts Block in this article for proper usage.

The pilot hole diameter of the current rotor (2/1/91 and later) is 7mm (0.28") larger than that of the earlier rotor (before 2/1/91), refer to Figure 1.


Figure 1 - Article 93-22-4

If a before 2/1/91 rotor (F1OY-1125-B) is installed on a vehicle built on or after 2/1/91, the rotor will not seat over the hub properly causing the rotor and wheel to wobble.

This can cause...

l Loosening of the lug nuts

l Breakage of the wheel studs

l Brake drag

l Accelerated brake wear

l Brake roughness

l Vibration

If the later style rotor (F2DZ-1125-A) is used on the earlier vehicle, a wheel runout vibration may result.


WARRANTY STATUS: INFORMATION ONLY

OASIS CODES: 301000, 306000, 390000

 

[Bizzy]

I had to read this topic this morning didn't I?

Two lugnuts off....two studs broken. Hey, I'm batting 100! Guess it's a good thing I'm going to be putting 96 brakes on.