Lug bolt won't torque - PeachParts Mercedes-Benz Forum

MCallahan · #1 12-30-2018, 02:23 PM

Sounds like they stripped the threads out of the hub. Only choice is to Helicoil or Keysert it. If there is enough meat, the Keysert is the best repair. Helicoils don't do well with repeated bolt removal, like on a wheel. Keyserts do fine no matter how many times you remove and install the bolt. Get four or five of the inserts, as they are dirt cheap and in case one comes out later (although it shoudn't). The tool is a bit spendy, but required to do the job. Either way, it's cheaper than replacing the hub, especially if it's the rear on a wagon.

https://www.youtube.com/watch?v=UTdJUMIcrPI

The damage may have been from over torquing with the impact gun, or could have been from galling coming out. Almost NOBODY ever anti-seizes wheel bolts. A friend runs a tire store and is careful to anti-seize EVERY lug bolt and nut he replaces for exactly this reason. A can of nickel anti-seize is just a few bucks and is worth it's weight in gold for preventing galling like this. Also put it on spark plug threads for the same reason. Thermostat housing bolts, etc... anything that goes in aluminum or acts like it might want to gall coming off or going on. Got hooked on using it at the pump shop taking apart corroded stuff and then at the hydraulic shop for large diameter fine threads. Sure makes life easier.

85 DSEL · #2 12-30-2018, 02:42 PM

Quote:

Originally Posted by MCallahan

Sounds like they stripped the threads out of the hub. Only choice is to Helicoil or Keysert it. If there is enough meat, the Keysert is the best repair. Helicoils don't do well with repeated bolt removal, like on a wheel. Keyserts do fine no matter how many times you remove and install the bolt. Get four or five of the inserts, as they are dirt cheap and in case one comes out later (although it shoudn't). The tool is a bit spendy, but required to do the job. Either way, it's cheaper than replacing the hub, especially if it's the rear on a wagon.

https://www.youtube.com/watch?v=UTdJUMIcrPI

The damage may have been from over torquing with the impact gun, or could have been from galling coming out. Almost NOBODY ever anti-seizes wheel bolts. A friend runs a tire store and is careful to anti-seize EVERY lug bolt and nut he replaces for exactly this reason. A can of nickel anti-seize is just a few bucks and is worth it's weight in gold for preventing galling like this. Also put it on spark plug threads for the same reason. Thermostat housing bolts, etc... anything that goes in aluminum or acts like it might want to gall coming off or going on. Got hooked on using it at the pump shop taking apart corroded stuff and then at the hydraulic shop for large diameter fine threads. Sure makes life easier.

Thanks for the recommendation on the Keyserts. I'm unfamiliar with such a solution but now I know! Are these available alacarte or would I have to purchase a bulk quantity? If you have a good source and a link I'd surely appreciate it.

Regarding anti-seize: it seems that I ran across this at some point. I've heard that it will interfere with torque value. Any knowledge on that?

Dale

Mxfrank · #3 12-31-2018, 01:12 AM

Quote:

Originally Posted by 85 DSEL

Regarding anti-seize: it seems that I ran across this at some point. I've heard that it will interfere with torque value. Any knowledge on that?

Dale

FSM torque values for wheel bolts are dry values for clean, rust-free threads. If you lubricate the bolt and use the same torque value, you will be applying more clamping force. That risks damage to rims, bolts and threads. The bolts are probably 25% below their load limit at specified torque, so you may have enough reserve strength to get away with it. But it's a still a risk you need to think about. If you know the thread size, you may be able to find a table of appropriate wet torque values by internet search.