OMFG I'm about to snap!!!! - Page 2 - PeachParts Mercedes-Benz Forum

Crazy_Nate · #16 01-12-2011, 10:07 PM

With that much torque...the female (male too, I'd say) thread surfaces are probably all galled. You might have some fun getting them near spec / standard.

Renntag · #17 01-12-2011, 10:11 PM

A friend of mine runs an independent Mercedes repair shop and this snapped lug bolt issue has popped up a few times. They go over to the tool rental place, get a gas powered chop saw, and cut out the center of the wheel, then slice through the piece that is left in order to release the hold of the broken lugs. I imagine either way something has to give. Speculating that after 4 or 5 hours of drilling, plus high dollar bits, you have to compare the cost of a replacement wheel.

For this reason I always use anti seize and torque to spec.

Crazy_Nate · #18 01-12-2011, 10:28 PM

Forgive me if I already know the answer, but doesn't a lubricant modify the amount of preload that you're applying? Different coefficient of friction, different preload for the same torque?

vstech · #19 01-12-2011, 11:08 PM

Quote:

Originally Posted by MTUpower

I had a tire pulled off a rim today ( the rim was bent) to put the good tire on a good rim. When the shop put the tire back on the tech started tightening in a circle and I stopped him to ask he tighten in a star pattern. He said this was not the first set of tires he's installed- yet continued to tighten in a circle.

I knew what to expect when he brought out the air tools and I insisted he NOT use them.

this personality needs to be pointed out to the shop owner, and fired. they will cost him money and customers in the long run.

kip Foss · #20 01-12-2011, 11:35 PM

From someone who learned the hard way; don't EVER use a tire shop that services trucks. Their air compressor is usually set to 175 psi. This pressure is all well and good if you are using a one inch spline drive on big truck tires or heavy equip. tires, but if you are working on a mini van it is a bit of an over kill.

Also ask the kid working on your tires what the torque should be. If he hesitates or doesn't know don't let him near your tires.

Many people recommend not using anti-seize but when you are broken down at 3 am and have rounded off the last nut and ruined the stamped steel tube wrench that came with the car you will rue the day you listened to these dunces.

If you car/truck/van/boat trailer etc. is over about 5 years the lug nuts should be removed, cleaned with a tap, lubed and torqued. In 55 years of driving all over the world I have NEVER lost a lug nut or bolt, much less and entire wheel, and I have lubed every single one on every car I've ever owned.

The lug nut lube conspiracy is like the change oil conspiracy. People think that if the owner's manual recommends changing oil every 5k miles then a 3k interval is better. In all the cars I have driven, and there have been a few, I change my oil and filter every 10K miles. I have never ever lost an engine to oil failure, and I don't know anyone who has. Maybe an oil pump failure or plugged oil passage but never a break down in the oil itself. So dealers or manufacturers or oil companies can say what they want but the reality does not bear them out.

Now, that said, I am sure that every person on this board can cite a friend of a friend that loss a wheel or an engine for too much or too little lube, but those weighed against the total number of drivers out there really don't amount to very much.

chrisbus · #21 01-13-2011, 12:24 AM

Call me naive, but I never even would have thought to have the tire shop use a torque wrench. I assume the proper torque specs are found in the owner's manual? I had my gen 1 "bundt" wheels on my SD replaced with the gen 2 wheels and got new tires. I had to go to the MB dealer parts dept. to get lug nuts, and they are NOT the kind that sit flush with the outside of the wheel (they are recessed). They work nonetheless. But I'm pretty sure the tire shop I used (American Tire, if I'm not mistaken) used an air wrench to put the lugs back on. I've taken it back once to have the tires rotated, and it's probably time to go in and have it done again.

How do I make sure I use the correct torque? I have a pretty nice torque wrench for my bicycle, but doubt that I could use it on my car wheels (right?)...

martureo · #22 01-13-2011, 01:03 AM

Quote:

Originally Posted by winmutt

FWIW Costco ALWAYS uses a torque wrench. I was very surprised by this and have found the to be the best deal around for tires once you throw in lifetime rotate balance hazard and nitrogen.

I'd still be very wary about "quickie" shops at Costco, BJ's, WalMart and Sam's Club (to name a few). It really depends on who is running it and who is working there.

Case in point, I worked as a supervisor at PepBoys (don't chuckle it was a second job to cover hospital bills). I personally hate PBs but they paid well. Anyway we started instituting a policy of using torque wrenches for all wheel removal jobs. Brand spanking new torque wrenches were bought and the mechanics and installers all instructed on what to torque to. About two weeks later I poked my head back in the shop checking on a customer's car when I noticed the one of the installers really torquing a lug bolt down. It looked to be an unusual amount of strength he was using so I asked if he set the torque higher or was the bolt just stubborn. He just looked at me and said "nope, I just want to make sure it's on there." Turns out he and most of the other installers were torquing until the "click" and then turning the bolt until they physically couldn't anymore.

EDIT: FWIW the torque wrench policy was instituted after an alarming number of wheel-offs. So I guess it was a step in the right direction.

Daman858 · #23 01-13-2011, 03:25 AM

There are probably more horror stories involving lug nuts and bolts than any other auto parts like when the guy puts the lug nut in the socket and trys to put it on the wheel lug and cross threads it. Shop I go to uses torque sticks which look like socket extensions and are colored for each torque value. They put the lugs on by hand first to make sure they are not cross threaded.

635CSi · #24 01-13-2011, 10:13 AM

So after spending several hours yesterday drilling, my hands are still numb and my wrists are aching I managed to get the rims off, it tuns out that most of the bolts were cross threaded so now its time for all new hubs. I still don't get why people in this industry just don't care anymore.

cscmc1 · #25 01-13-2011, 03:11 PM

Quote:

Originally Posted by chrisbus

How do I make sure I use the correct torque? I have a pretty nice torque wrench for my bicycle, but doubt that I could use it on my car wheels (right?)...

I don't recall what W123 torque spec is, but you can find this out easily enough. The manual ought to list it (might be in nm rather than ft lbs). You can pick up a torque wrench cheap enough at Harbor Freight; you'll need one that can be adjusted to your specific wheel torque (probably 80 or 90 pounds). IIRC, mine goes from about 30 pounds up to a few hundred. More than likely, a torque wrench that's useful for a bike won't do you much good for automotive lug nuts.

babymog · #26 01-13-2011, 03:35 PM

Torque sticks are good, but IMO a good torque wrench is better for final torque. I carry a torque stick for my motorhome wheels since I've had three studs sheared (torque spec is 450-500lb-ft) by a local tire shop mobile service, ...

Lubricated thread torque should be reduced from the dry-thread spec, IIRC it is around 20% reduction (best to check). The bolt is designed around a clamping load (tensile load) on the bolt, and it is acheived with less torque with lubricated threads. Personally, I lubricate all lug bolts/nuts with never-seize, but I do my own rotations and check torque periodically. Never have I found a loose one, ... but still checking.

DO NOT put grease or any lubrication on the bolt seat, nor on the wheel-to-hub interface. I believe it is okay to never-seize the hub flange where it inserts into the wheel center bore, but nothing else, ESPECIALLY the bolt and rim where the two touch at the ball-seat, that is the friction that will keep your bolt tight.

Hatterasguy · #27 01-13-2011, 03:46 PM

Quote:

Originally Posted by 635CSi

So after spending several hours yesterday drilling, my hands are still numb and my wrists are aching I managed to get the rims off, it tuns out that most of the bolts were cross threaded so now its time for all new hubs. I still don't get why people in this industry just don't care anymore.

Wow that sucks, if that was my car I would take the shop that did that to small claims.

I always watch the tire monkey's, and have had to stop them a number of times.

When I first got my truck I had a small local shop balance the tires. A couple of months later I was going to rotate them, but I couldn't get the freaken nuts off! I was standing on an 18in breaker bar with a pipe extension and I weigh 200+ and they wouldn't move, they were starting to round!

I was like WTF so I drove it right back and told them to undo them now, and whatever breaks they are fixing. Luckily they got them off, and I had a new set at home.

pawoSD · #28 01-13-2011, 03:49 PM

I've gotten to the point where I just bring the wheels to the shop and have them do the tires/balance, then I bring them back home and mount them up. If I do bring the car, I watch them like a hawk.

lutzTD · #29 01-13-2011, 04:23 PM

Quote:

Originally Posted by pawoSD

I've gotten to the point where I just bring the wheels to the shop and have them do the tires/balance, then I bring them back home and mount them up. If I do bring the car, I watch them like a hawk.

thats where I am too, they say they wont warrantee the tire but I tried to use a warrenty once and they screwed me. As far as rotating I do that myself to check the brakes anyway. they always wanted to sell me something whenever I let them rotate them. the last time I let them, some 20 years ago, they left the lugs loose and I heard popping until I could stop and check them tighten them myself

mechmagcn · #30 01-13-2011, 04:31 PM

I too have had the problem of heads breaking off of the lug bolts. I found that a few sharp strikes to the bolts with a drift and a large hammer will get them to come out without breaking. For the ones already broken, I will strike it with a hammer and then drive a cheap 12MM socket onto the remaining piece, usually they will come out easily.
FWIW, torque sticks are a joke. Unless you know exactly what the air impact is putting out, you cannot know what the torque stick will allow. I have proved this to several tire shops with a good torque wrench.