Need some pro advise....

[3_milly871]

Hey JMBT as for those bolts that backed out,... they maybe stretch bolts and usually what happens through the constant heat and cooling process after the first installation from the manufacturer the bolt cannot hold its original torque (strength) kind of like cylinder head bolts ........for example: usually when you change a cylinder head all of the mounting bolts that fasten the cylinder head down to the block ,....... the manufacturer will usually advise that these bolts be replaced after removal to guarantee proper torquing because these parts are under great pressure ....... just my thoughts good luck hope that lock tight works....!!

[JMBT]

Update...ran 100 miles this morning pulled over to check torque on bolts. Set wrench at 124 ft/lbs, 5 under what I torqued them to yesterday when I put everything back together. All of the bolts turned minutely to click at 124 ft/lbs. meaning they had definitely backed off some. I reset the wrench and torqued them all to 129 ft/lbs (cummins spec) and ran another 100 miles. This time most had held the torque of 129, 4 of the twelve turned minutely in order to click at 129.

Going over what I did yesterday: removed all bolts, pulley, and plate in front of pulley. Cleaned mating surfaces of pulley and plate. Cleaned all bolts with wire brush and carb cleaner. Made sure dampener was properly seated. Applied blue loctite to bolts. Ran them in until tight. Then torqued them with a brand new torque wrench to Cummins spec.

I will continue to check them on my next little run. If they continue to back off the set torque I will replace the bolts with new ones and apply red permanent loctite before my next pickup on Thursday. If that doesn’t work I will have exhausted all I can do without pulling the front end off again, so I will head back to my brother’s house tear the front down, and spot weld those little motherfuckers to the vibe dampener.

I am at my wits end here, hopefully it won’t come to that.

[dhirocz]

Be careful with that threadlocker...I've torn out threads trying to remove bolts put in with that stuff...

[Hammerhead]

I understand your frustration completely, hope it doesn't come to that.

I have torn out thread with loctite as well, but never on anything hardened like a crankshaft. I wouldn't worry about it in this application.
Aluminum, oh hell yeah! You'd best heat the bolts first or you will be installing heli-coils...

[dhirocz]

In all fairness, it was threadlocker red into cast iron. Someone assembled an engine with it all over the main bolts. Ended up ripping the threads out with the bolts, which probably about had it at that point. I don't even think Id try threadlocker into aluminum. I don't think I've ever needed to honestly.

I just tell folks to be mindful if they need to service something later on before they use locktite, or people will put that red stuff on valve cover bolts.

I don't know if those bolts are torque to yield or not, but being that they are suspect, I'd replace them anyway. Last thing you want is to find out they were overstretched when you twist the head off of one. Eww.

[Nilao]

I always use threadlocker blue. Never red unless it is a bolt I never want removed. I had to do hub assemblies on my 3500 one ton and the twats at the factory had used red locktite on the bolts. I had to heat them with a torch to have any chance of breaking them loose. Needless to say they went back together with blue locktite.

[JMBT]

Update: it has been 2750 miles since the last go around and everything is staying tight. I checked torque every 100 miles for awhile, then 500, then 1100, and there has been no backing off of the bolts off the 129 ft/lb torque. I still don't have a definite answer as to what went wrong, and that bugs me to no end.
Thought I would share this, (it is scary): I talked a buddy of my brother's about what happened. He has been a Cummins wrench for about 25 years, and has a very good reputation in California. He said when they change a dampner at the shop, they apply blue loctite from the git-go, not oil as Quickserve recommends or antiseize, and (here's the scary part), they put the bolts on with a 1/2" impact AN DON'T CHECK THE TORQUE!!! WTF!!
Anyhow, that takes away any fears I had of streching the threads, if my torque wrench was out of whack by a little.
Also, he said they always reuse the same bolts unless they are damaged, as they are not a one time use bolt.

[Rawze]

(12-06-2017 )JMBT Wrote:  Update: it has been 2750 miles since the last go around and everything is staying tight. I checked torque every 100 miles for awhile, then 500, then 1100, and there has been no backing off of the bolts off the 129 ft/lb torque. I still don't have a definite answer as to what went wrong, and that bugs me to no end.
Thought I would share this, (it is scary): I talked a buddy of my brother's about what happened. He has been a Cummins wrench for about 25 years, and has a very good reputation in California. He said when they change a dampner at the shop, they apply blue loctite from the git-go, not oil as Quickserve recommends or antiseize, and (here's the scary part), they put the bolts on with a 1/2" impact AN DON'T CHECK THE TORQUE!!! WTF!!
Anyhow, that takes away any fears I had of streching the threads, if my torque wrench was out of whack by a little.
Also, he said they always reuse the same bolts unless they are damaged, as they are not a one time use bolt.

I find it sad how there are so many so-called trained professionals who just don't care about the quality of their work. they spread bad practice and shortcut methods like a disease in the truck service industry. When someone speaks out to hold them accountable for their actions, all they get is grief and arguments in return.

It is sad because you pay top dollar for such debauchery, then have to resort to learning to become your own mechanic if you want anything to be performed correctly on your equipment so that you can stay reliable and profitable. It should not be this way. There is no excuse for it at all. Corporate greed and improperly paid mechanics who are not only undereducated, but also pushed to the point of not having time to care at all outside of "get the next truck in here" because they aren't getting paid to use a torque wrench,.. they are getting paid to get that truck out and the next one in by whatever means and shortcuts necessary to make their bosses happy at the direct expense of the truck owners equipment.

Its only cure it to stop giving them your hard earned money and tell them to keep that air-tool happy moron of an over-paid, under trained mechanic away from your truck.

[JMBT]

I totally agree Rawze! When I hear stuff like that it makes me very happy that in 636K my truck has never been to a shop!.....and that guy was a 25 year Cummins mechanic!!!