Nearly a catastrophic failure. What could cause lug nuts to self-loosen after front axle rebuilt? (1 Viewer)

[baldilocks]

Funny that this thread came up when it did because I lost a tire on I80 last Sunday afternoon. Yes it sucked! I continued with four nuts on the spare tire wheel.
I have been reading and trying to figure out why this happened two weeks after installing the tire/wheel assembly. I have put many a tire on many cars and never had one even begin to come loss. And I have used anti-sieze compound before and just may have this time. Have never used a torque wrench either, just good and tight. This is not my first Toyota but it's my first with aluminum rims. All I know is that I will refrain from the use of any lubricants and use a toque wrench with re-torque after 50 miles or so and a check up after every off road run because loosing a 35 at 65mph isn't my idea of safe and sane fun.

 

[scottryana]

Just be careful not to torque when hot either. Lol.

A lot of new track guys will take their torque wrench with them to the track set it at 100ft/lbs and after each lapping session run around the car and torque all the lugs. I have seen more studs snapped off after 4-5 repeat sessions than any other way.

 

[MarkM]

I had the same thing happen to me a few months back. Wobble one the highway, got worse for a few miles, got worse when I swerved side to side. Got to work, all 6 nuts were hand loose on the drivers front.

From that point forward, I have been torquing to 100 ft lbs.

Pretty sure that I read two different recommend torques depending on what kind of nut it is.

 

[scottryana]

The torque value changes depending on if it's the aluminum wheel or steel wheel I believe. I have always done 77ft/lbs on the late model aluminum wheels and never had issues even with wheel spacers. (Knock on wood)

 

[gandrimp]

My FSM shows 108 ft lbs to be the lug nut torque.
Rear axle hub components section.
It also doesn't give different torque for steel verses aluminum.

 

[MarkM]

Reading through all of this, and it appears I have conical lugs on my aluminum wheels on a 96. So would that mean the correct torque would be 108 ft lbs, since I don't have the nuts with washers?

Sorry to highjack.

 

[scottryana]

^^^^sounds like your wheels were swapped out at some point.


From Cdan himself


"Lug nut torque specs are as follows:

All steel wheels...109 lbft.
Alloy wheels with conical steel inserts (91-94) 109- lbft.
Alloy wheels 95-97 (shank-type nuts) 76lbft "

 

[1973Guppie]

to me it sounds like the OP did not set the wheel bearings to the proper spec and that caused enough movement to allow the wheel to slowly rock itself loose. New wheel bearings break in. I usually go 20-25 with new wheel bearings as I know they will break in a bit.

 

[MarkM]

^^^^sounds like your wheels were swapped out at some point.


From Cdan himself


"Lug nut torque specs are as follows:

All steel wheels...109 lbft.
Alloy wheels with conical steel inserts (91-94) 109- lbft.
Alloy wheels 95-97 (shank-type nuts) 76lbft "

Yeah, looks that way. I'll have to take a look at the wheels the next time I have them off and look in more detail. And I did see what Cdan wrote, and re-read when I had my loose wheel incident. Looks like 109 for me!

 

[FJP971]

^^^^sounds like your wheels were swapped out at some point.


From Cdan himself


"Lug nut torque specs are as follows:

All steel wheels...109 lbft.
Alloy wheels with conical steel inserts (91-94) 109- lbft.
Alloy wheels 95-97 (shank-type nuts) 76lbft "

I know you are quoting CDan here but what is a shank-type nut? This link (A Few Facts About Lug Nuts - Performance Plus Wheel and Tire) given earlier does not use that name for any of the lug nuts shown.

I'm going to double check mine but what I recall is they look like the "mag-type hex nut" except they have a tapered end. The built in washer on mine does not seat against the rim like the examples so I might not have the correct lug nuts for a stock late model aluminum rim. Thanks in advance.

 

[scottryana]

What he is calling a shank type is the later lug nut that is not conical. You could really just say early - conical, later - flat with washer. If your wheels and lug nuts don't match, you need to remedy that

Disclaimer I am drugged up on Percocet right now but I believe that is the break down.

 

[Whileemptyheadsdream]

to me it sounds like the OP did not set the wheel bearings to the proper spec and that caused enough movement to allow the wheel to slowly rock itself loose. New wheel bearings break in. I usually go 20-25 with new wheel bearings as I know they will break in a bit.

I did this as well, rotate all wheels , one came loose, Sholder of lug was not seated properly, I felt It moving. I wondered and then I heard It tapping and I knew what I had done.

 

[canman]

This is really interesting to hear of more stories of wheels coming off or loose. Like @baldilocks, a buddy had his DS front tire come off going down the freeway. A week or so earlier, he had taken it to a shop to do some work. I have the OEM steelies, and have never had issues, but I do seem to recall that with the OEM alloys, they were always very tight fitting over the hub due to corrosion or what not. I'm wondering if sometimes the rim is not properly seated due to interference with the hub, misleading one to believe the lug nuts are properly torqued, but in fact the rim is not properly seated to begin with.

 

[lazy]

most factory wheels are what is known as hub centric. They are bored out to fit tightly over the hub. This is usually the best for quality of ride. I've been out of the tire and wheel game since my high school days in the late 90's, so I know a lot has changed. But, when you go to wheels which aren't hub centric, they are known as lug centric, which depends on the lug nuts to keep the wheel centered to the hub. In the 90's, you could just about mark the same day every month on the calendar when the guy with lug centric after market wheels would come back in for a vibration issue. We would rebalance (which usually no change was needed), and then torque the wheels in the air. And he would have the same problem.

Point is, yes it is tight fitting over the hub and for good reason. If there is corrosion or dirt on the hub, clean it off and grease it. If your studs are corroded, clean them off and put anti-seize on them. If your studs are in poor condition, replace them. You are more likely to break or weaken a stud from the torsional forces applied from removing or installing a lug nut which is corroded than you are from an uncorroded, good condition stud & lug nut which is lubricated, which may or may not have too much (I would argue small and negligible) axial force.

AND ALWAYS retorque after 50 miles or so.

 

[NBender]

to me it sounds like the OP did not set the wheel bearings to the proper spec and that caused enough movement to allow the wheel to slowly rock itself loose. New wheel bearings break in. I usually go 20-25 with new wheel bearings as I know they will break in a bit.

When I did the rebuild, I set the wheel bearing pre-load to somewhere around 10 ft. lbs. for each wheel following the FSM procedure using a spring-scale. Can you clarify what you mean by going to 20-25 for new wheel bearings? Do you mean that you set the pre-load higher to 20-25 ft. lbs.?

 

[greentruck]

What he is calling a shank type is the later lug nut that is not conical. You could really just say early - conical, later - flat with washer. If your wheels and lug nuts don't match, you need to remedy that

Disclaimer I am drugged up on Percocet right now but I believe that is the break down.

Yep, that's it, with the additional note that "flat with washer" is the same thing as "shank style."

 

[1973Guppie]

When I did the rebuild, I set the wheel bearing pre-load to somewhere around 10 ft. lbs. for each wheel following the FSM procedure using a spring-scale. Can you clarify what you mean by going to 20-25 for new wheel bearings? Do you mean that you set the pre-load higher to 20-25 ft. lbs.?

I stopped doing the spring scale thingy years ago. My process: inner nut tight so can't rotate wheel to seat everything, back off, tighten inner to 20, rotate wheel to ensure everything smooth, outer to 45, bend tabs and be done with it.

From my experience the spring scale has goofed me up to being usually way too loose. It is just more consistent with the above method.