Lug bolt threads

[Chris Haney]

Had new tires put on my new 240D Saturday. Seems one of the lug bolts threads are messed up. I've ordered the new bolt but would like to clean out the female side.

What is the tap spec for this?

[P.E.Haiges]

Take your lug bolt along to where yu are going to get the tap and match them up.

Try another lug bolt in the hole with the stripped threads after tapping and torque to specifications to see if the threads will hold.

Be advised that if the female threads are stripped, tapping them will not fix them. Once they are gone you can only fix them with a helie coil or replace the part that has the stripped threads.

P E H

There are two different lug bolts, depending on which wheel you have. You might want to check the MB manual--lots of detail on the wheels.

[autozen]

I have seen many stripped lug bolts through the years, but there is only one cause. Someone has been using a high speed and high torque air wrench to remove or install them. Lug bolts and nuts are not lubricated and have relatively fine threads. Turning them rapidly causes high heat from friction which causes the fastener to seize. Since the high speed air wrench caused the problem, it also has the power to still get the bolt out and destroy the threads. I'd keep an eye on the tire guy and watch what he uses to install and remove your wheels. Some shops use torque wrenches or torque sticks to install wheels. Unfortunately too many shops still use the biggest gun available. The wheel will never come off, but you better not have a flat. You'll never get the lug bolts out without a 10 foot cheater bar.


Peter

[P.E.Haiges]

Peter,

I agree. I watched a tire changer use a air gun to replace wheels on my old Valiant. It looked like he fell asleep while "pounding" the nuts on because he "pounded" so long. After he was finished I handed him the factory lug wrench and asked him to loosen the lug nuts. He couldn't loosen one. So I had him loosen all the nuts with his air gun and retighten with my lug wrench.

When asked how I was supposed to remove the wheels somewhere on the highway, his answer was "DUH" I complained to management and they told me the air guns were set to the correct torque. When I told them they were full of s***, they got an "I don't give a s..." attitude.

I don't go that establishment anymore. I wonder how many people got straded when they couldn't remove their lug nuts when they gat a flat tire.

The only place where I saw a tire shop use a torque wrench was in Canada but it was a long time ago and I can't remember where it was. They also immersed the tire in water after mounting to check for leaks. I had respect for that place and I complimented them.

P E H

[the_good_fellow]

Discount Tire did that to my SDL with air tool. I couldn't get two of them loose on LF wheel. So I took it back there and had them re-torque but they broke one of them. The manager said the design of stems were weak...after so many turning and twisting it would break or bent. He suggested me to get some new lug bolts and had the broken drilled out by a shop he referred. I went to that shop and they wanted $150 for that
HELL NO! It took me well over 4 hours and 6 drill bits to get it out. Now I can only use that wheel as spare b/c that hole is pretty much mess up...

[the_good_fellow]

it's located at hwy6 and Westheimer. It was late in the evening...u know.
SDL has those weired lug nuts with a slim waistline...most of them are bent or crooked. Dealer wants $8.5 each...just ordered 20@$5.00 each from Fastlane.

[autozen]

Good Fellow,

If you have stock wheels and stock lug bolts, that manager was blowing smoke up your butt. There is nothing weak about the design, and you can remove and install them as often as you desire without a problem.

Peter