Threadlocker for oil-soaked cast iron?

Question

I recently tore down an automotive transmission I rebuilt. Some bolts that were threadlocked with Loc-tite red came loose and locked up the unit. These bolts were threaded into the cast-iron differential cage.

This time I intend will clean the parts extra thoroughly with solvent. In retrospect I probably didn't get all the oil off the thread surfaces the first time. But I'm still worried that absorbed oil in the cast iron will prevent a good bond.

Would the wicking type loc-tite work better? Or should I use the extra-permanent oil resistant stuff?

Dave

clare at snyder.on.ca · Accepted Answer

Clean with MEK, then use activator. And torque to spec.

Rex · Answer

There are some varieties of LocTite and Permatex Thread-Lock that work with oily surfaces.

David Geesaman · Answer

Right.  Is it better to use one of these, or try to clean the cast iron well with solvent and use the regular high-strength stuff?Dave

Tony · Answer

I wonder what properties of Loc-tite actually lock the bolt to the nut. Is it the adhesive bond between the 2 metal surfaces, or does the Loc-Tite merely "fill in the space" between the threads, solidify, and cause the bolt/nut to bind? If the latter, then having oil soaked cast iron shouldn't matter as long as there isn't so much oil so as to dilute the Loc-tite and prevent it from solidifying.

Tony

kfvorwerk · Answer

Why not look it up here.

David Geesaman · Answer

I did.  Hence the question of which one works best.Dave

kfvorwerk · Answer

Just checking. Sometimes people don't do their homework. You wouldn't belive (or perhaps you would) how many people ask me to find something on the internet they can't find and it's one of the top 10 hits on Google when you phrase it right.Hope things stay together for you.Karl

Threadlocker for oil-soaked cast iron?

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