13

A few months ago, I picked up a cheap 2005 4Runner V8 2WD, which had a slight front-end vibration that I wisely ignored until recently.

A week or so ago, I felt a pretty severe thunk from the front LH wheel, followed by another thunk per wheel revolution. I managed to nurse it home. When I jacked it up and removed the wheel center cap, I saw this: Missing Lug Nuts

After removing the wheel, I saw this: Three Broken Wheel Studs

I was able to tap out the broken studs and replace them with some generic O'Reilly studs and new lug nuts.

enter image description here

Question What, other than over-torquing the lug nuts as tire shops are known to do, would cause this? These overly-blingy 22" aftermarket wheels also may be thicker than the stock wheels where they mate with the hub. I'm wondering if these require longer wheel studs.

Another disturbing phenomenon: one of the missing lug nuts fell out when I removed the center cap. The other two missing ones were nowhere to be found. This, to me, implies that the last person to put the wheel on didn't bother installing them. Thanks a lot, Tire Shop Dude. It's not like I use this thing to cart my kids around or anything.

| improve this question | |
  • 5
    In your middle photo, studs at 2 oclock and 10 oclock are corroded on the end, implying they were already snapped off. I suspect that these did not have nuts on them, and the stud at 12 oclock (the shortest one) was the one that snapped when you were driving, due to excessive stress because the two adjacent ones were already snapped and without nuts. – Level River St Dec 25 '19 at 23:00
  • @LevelRiverSt Based on the length of the stud segment that was in the lug that fell out when I removed the cap, I'd say you're right. At least the genius who did this had a sense of symmetry. :) – 3Dave Dec 28 '19 at 2:32
  • Did you figure this out? Is there some kind of spacer between the hub and the rim? – Sir Swears-a-lot Jan 16 at 1:41
  • @SirSwears-a-lot Best guess is that somebody overtorqued the lugs and the studs snapped off. They chose not to inform me. I just replaced the studs and put it all back together. The wheel is doing fine so far. There are no spacers. I put the wheels on a couple of 4Runner lists for trade for the stock set; doubt I'll get any bites, but it's worth a shot. – 3Dave Jan 16 at 1:43
  • 1
    Just thinking more about your comment, you asked if maybe the studs weren't long enough. I beleive if they weren't long enough they'd be more likely to strip threads than snap or shear off. – Sir Swears-a-lot Jan 23 at 1:44
8

Overtorque is the most common reason in my experience. The next most common issue is corrosion/seizing which then breaks the stud when you try to apply enough torque to remove the nut.

Always use a torque wrench and apply anti-seize to prevent future problems.

If those are pressed in studs you may be able to press them out and replace them. Otherwise you'll likely need to replace the hub.

| improve this answer | |
  • Thanks. I was able to tap them out (gently) with a hammer and replace them with some generic studs from the local parts store. It only took about an hour. The bearing has no play. I was trying to think of a way that three lugs could be sheared off, and nothing comes to mind. – 3Dave Dec 24 '19 at 17:01
  • Another interesting point: the remaining lug nuts were only finger-tight. (And I use the word "tight" very loosely here.) – 3Dave Dec 24 '19 at 17:05
  • 11
    You may want to replace all of them. The unbroken ones may be compromised from the same conditions that broke the others. The finger-tight issue indicates that the studs may have "stretched". This is what happens when gorillas work on cars. – jwh20 Dec 24 '19 at 17:05
  • 1
    Good point. I was wondering about that just now. I have to replace the front pads, anyway. While I was taking everything apart, I found that the pads were only ~2mm thick. Someone did not take very good care of this thing. (On the up side, the engine still runs perfectly.) – 3Dave Dec 24 '19 at 17:06
  • 3
    I would completely agree with you the most likely cause of this was overtorque. I'd also wager the (not so bright) person who put this wheel on at the store just did the nasty and threw the wheel back onto the vehicle as is (clue: missing lug nuts and studs ... they don't just evaporate). As far as using a torque wrench, not only should they be used, but should be used correctly. I've seen more often than not where the "Tire Shop Dude" just wrenches over on the torque wrench applying torque until it stops and not paying a lick of attention to the "click". Argh. Good answer: +1 – Pᴀᴜʟsᴛᴇʀ2♦ Dec 24 '19 at 17:58
17

Fatigue failures of UNTIGHTENED studs ; been there ,done that. When loose , apparently the wheel moves enough to cause fatigue. Fatigue ( axial) fractures are flat as shown in photo. Replace all the studs , it is cheaper than trying to check them for fatigue cracks. I did it on a Nissan Titan , left one front wheel finger tight and drove 900 miles and did not die. I stopped several times to check tire pressure because I could feel "something" in the steering ( smooth interstate), increased pressure. When I got to destination I was sure I had a bad wheel bearing. When I looked at the wheel - NO nuts. Three studs ( of six) were broken -fatigued flat like yours. I pushed out the stud remains and replaced ; otherwise no problem . A week later my son found half a broken stud with nut in the gutter, it had broken off as I made the turn onto his driveway. PS ; I did metallurgical failure analysis for a living.

| improve this answer | |
  • This was a hard learned lesson for my teenage self about air regulators. After my dad had done some painting, the air regulator was left turned way down in the shop. Used an air wrench to tighten a wheel on my truck- drove and kept hearing a knocking sound. I checked all the wheels, nothing was apparent. 45 minutes of driving later, the tire falls off and goes bouncing down the road. The failure looks exactly what the OPs picture shows. – Aww_Geez Jan 16 at 22:06
11

It may be that the rims you have are the incorrect size for your hubs. The hub center in your photos show light rusting where id expect to see some wear or rubbing from contact.

Wheel studs are not intended to hold the weight of the vehicle vertically. They are designed to hold the rim sideways against the hub center. The rim should press firmly onto the hub center which bears the load.

| improve this answer | |
  • Excellent point - OP does describe them as blingy aftermarker 22" which may be unsuitable. – Criggie Dec 25 '19 at 21:18

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.