check your lug nuts + torque wrench madness

[s219]

I put about 150 miles on a new trailer, and remembered to check the lugs last night. At least one lug on each of the four wheels took an honest half turn before tripping the torque wrench at 95 ft-lb. The rest were OK.

Oddly, my torque wrench stopped working about halfway through the job. Couldn't figure out why this would happen, since it was working fine last time I put it away.

Well, I took the ratchet head apart, examined everything to figure out how it worked, and found the problem -- whatever grease had been in there was all gummed up and had turned into varnish. This was preventing the ratchet mechanism from working, and it was stuck in a free wheeling position. I cleaned everything out, put new grease in, and went back to work.

And that's how a simple one-minute check of 20 lug nuts turns into a messy 30-minute job. Story of my life. I don't know what kind of lubricant Craftsman put in that ratchet mechanism, but it sure gummed up pretty bad. The wrench is about 14 years old.

 

[texasjohn]

Do you think that this is the way it was initially, or that the nuts loosened with use?

 

[brokenot]

At least one lug on each of the four wheels took an honest half turn before tripping the torque wrench at 95 ft-lb.

Lug nuts on new trailers should always be torqued at the dealer, but it often doesn't happen. To save $$ on freight charges, many dealers order four or five trailers at a time and they arrive stacked on top of one another on a semi trailer separated by wooden cribbing. Stacking them requires removal of the wheels/tires, and it's up to the guy unloading them to install the wheels and make sure everything is tightened to spec.

When the semi driver is there waiting to be unloaded, the wheels get put on, (often with a cordless drill or impact), and the trailers get off-loaded with a forklift and set on the ground so the driver can be sent on his way.

When buying a new trailer, ask for a photocopy of the checklist the dealer goes through before the trailer goes out the door. If they don't have such a list, then tell 'em to at least get a paint marker and put a dab of paint on each stud/nut as they're torqued.

 

[RickB]

All lug nuts should be retorqued after a brief run regardless of whether or not they were done at predelivery. You would be hard pressed to find an operator's manual or tire shop invoice that didn't say so in plain English.

 

[s219]

The dealer checked the lug torque right there in front of me when we hitched up the brand new trailer, so I know it was OK to start with. But with trailers, you really need to recheck the lug torque after 50-100 miles.

On the last trailer I bought, they gave me a bright orange piece of paper that had a reminder to check the lugs after 100 miles, printed in large font. So it must be a real concern for trailer shops.

 

[xtn]

It should be a concern with anything that has wheels. When new lugs are torqued cold, they will stretch when subjected to a couple of heat cycles, even if the nut doesn't turn, they will loosen.

Re-torque and THEN put on your paint.

 

[RobertN]

If you had to take your torque wrench apart, I would question its accuracy.

Had interesting discussion with some thermo-mechanical engineers a while back. Most torque wrenches are never re-calibrated after they leave the factory; typical spec is yearly. Most TQ wrenches should be stored properly, with tension relived; ie don leave it at 95ft/lbs or whatever you last use was. An, most TQ wrenches, even if they have a lot of adjust-ability(ie 50-250 ft/lbs) are only accurate in the middle of that range; as you get to the lower range or higher range of the wrench, the accuracy drops off, sometimes significantly. Then there is level of quality of the wrench; don't expect a Harbor Frieght 50% off sale TQ wrench to read like a just calibrated Snap-On.

 

[Diamondpilot]

As mentioned, do not store you wrench set, zero it back.

As far as lug nuts on trailers go they should be torqued to 120 ft lbs. I have over 75 trailers I maintain and have owned over 20 personally and all have required them to be torqued to 120 ft lbs.

Chris

 

[jeffsw6]

I personally wouldn't trust a hammer that said Craftsman on it, let alone a torque wrench. I'm sure there was a time when Craftsman made good tools, but it must have been before my lifetime.

 

[gengine]

On my newer trailers, there is a sticker on each wheel, including the spare, that says something along the lines of checking tightness of lugs before every trip. Although it says nothing about torque specs. I've seen a few tires going across the interstate without the trailer. Kinda funny, but still makes you wonder how many people have been hurt by that sort of thing, and how many actually check them, ever.