I was wondering whether anyone had heard of a Paralever swingarm failure attributed to overheating the FD pivot bolts to unlock the Loctite thread sealer. I read on another forum that overheating could cause small fractures, stressed points, or latent weaknesses in the aluminum cast that could later erupt into a total swingarm failure at the pivot bolt points. The reason I'm asking is that I recently took my FD off (metal flakes in the oil) and needed to really apply the heat gun for about 10 minutes directly to the right-hand bolt before I could break the Loctite's hold. On inspection, Berlin had used an exorbitant amount of thread locker. I was slathered everywhere on the bolt, even on the flat undersides of the bolt's head. Well, by the time I was able to break the Loctite's hold, the swing arm was hot to the touch (you might be able to put your finger on it for a second, or so) and this heat radiated pretty much all the way up the arm, being aluminum, although it was only "very warm" 6 to 8 inches up from the bolt. With only a little touch of the dramatic, am I riding a bomb now? :huh And I'm no lightweight--at 280 I need that sucker to be as strong and capable as it can be and I could envision the thing giving up as my fat ass is being hauled down the interstate. Hopefully, I'm just being paranoid. Damn Loctite-loving Germans!
You're not riding a bomb you're riding da' bomb. Ride and enjoy and stop fretting. The closest thing to explosive on that bike is your ass after a 5 pepper chili meal.
A good indicator of excessive heat applied to any of the castings is discolored paint. A heat gun, if used properly will likely not produce a high enough temperature to change the metal structure. Now, a tourch? That might be a different story although I use a torch when I melt Loctite on my GS Paralever. Use common sense and all will be well.
Like was said, this is not an issue. You would have to seriously overheat the swingarm to cause it structural damage. I don't think it is possible with a standard heat gun, and you would have to really try with a torch! Jim
how much heat do you think is produced in the internals of the engine. And the stresses in each engine revolution . Do you worry it exploding.
To get the final drive hot enough to change the metalurgy one would first smell burning paint, oil, gaskets, etc. Don't sweat it... Q~
I just did the same disasemble and I used a infared thermometer and you'd be surprise how much heat is spread.. no worries..
The paint on the swingarm is epoxy powder. It was heated hot enough to melt it in a big oven, without damaging the aluminum. A110 V heat gun only about 3000 BTU , you would need to melt the paint before you would be exceeding the temperature the swing arm was baked at. on a casting that big 3000 BTU is not going to get there.
Thanks, everyone, you've put my increasingly feeble mind to rest. I just didn't think I'd have to heat the livin' shite out of the pivot bolts like I did--concentrating all that heat in in one spot got me worried, particularly after I saw a picture of an R1150 Rockster with the swingarm snapped off at the pivots. The guy claimed it was caused because he put too much heat on the bolts. It was a pretty greusome failure, although I don't think the guy was hurt. A little knowledge from the internet is a dangerous thing.
I have removed the same pivot bolts (BMW calls them the "floating bearing stud bolt" and the "fixed bearing stud bolt") using a propane torch to melt the Loctite. By concentrating the flame on the steel bolts, the Loctite melts with little heating of the surrounding cast housing. It doesn't take much heat...250 F. is adequate. Have your 12 mm hex wrench at the ready to break the bolts before they cool.
