rusted engine mounting bolt

[gmlaverda]

I am disassembling my recently acquired 1969 350 Scrambler. I managed to easily remove all of the engine mounting bolts except the one on the top of the crankcase. This bolt was heavily rusted and stuck to the frame. I carefully ground the head off, drilled into the bolt a ways. It still would not move, but at least I could persuade the engine out of the frame. Now I have an engine on the bench with the entire length of bolt still inside. Hammer taps do nothing. So I have been soaking with a penetrating fluid. Any other ideas on how I can get this bolt out? Thanks

[Bevel bob]

If you have lost both ends of the bolt you will be in some difficulty!!, the bolt may be stuck in one half of the case only, so I would carry on with the disassembly and soaking,if the cases separate you will have more to work with.Locking 2 nuts on the thread may help,as will heating the cases in an oven,which you will be doing anyway.

[LaceyDucati]

Probably worth a gentle even heat up with a gas torch. A combination of that and penetrating oil should eventually do it, though watch out penetrating oil is flammable! Try not to belt the bolt too much and bell the end as that will only make things worse, perhaps drill a short 1/4 hole in the centre of the bolt and use a drift to tap down that. This will avoid too much brute force and avoid any spreading of the end. failing all this, maybe a job for a machine shop, to mill out with a slot drill and drill.

Best Wishes Nigel

[gmlaverda]

I have actually tried hammer taps on both ends, with a drift on the rusty end and with the nut secured to the threaded end. Not a budge. I also tried a few minutes of heat from my plumber's torch to no avail. I guess it may take several cycles of soaking in penetrating fluid and heat and lots of patience. thanks all

[amartina75]

If you have enough to work with at one end you could try
drilling and tapping the bolt and using a slide hammer
to try to pull the bolt out. Using slight heat at the same time

[LaceyDucati]

Good Idea, will avoid the bolt shank mushrooming/belling. Many minds......

[Magman]

Try mixing 50/50 Acetone and automatic transmission fluid(ATF) for the best penetrating fluid


http://www.practicalmachinist.com/vb/ge ... il-196347/

A study done by Machinist's Workshop magazine in their April 2007 issue looked at different penetrating oils to see which one did the best job of removing a rusted bolt by measuring the pounds of torque required to loosen the bolt once treated. If the study was scientifically accurate, it turns out a home brew works best!
Here's the summary of the test results:

Penetrating oil ..... Average load

None ...................... 516 pounds
WD-40 ................... 238 pounds
PB Blaster .............. 214 pounds
Liquid Wrench ...... 127 pounds
Kano Kroil ............. 106 pounds
ATF-Acetone mix....53 pounds

[gmlaverda]

I was planning to source some Kroil after hearing great things about it, but I may just try the home-brew instead. Thanks for all of the ideas.

[gmlaverda]

Well today I finally won. After almost 2 weeks of daily applying 3 different penetrating fluids as well as heat from a propane torch early on, today I spent several minutes with the torch heating the crankcase where the bolt resides. A few good whacks with a drift and a hammer…movement. More fluid and I hammered it out. The entire length of the bolt was rusty but fairly smooth. Amazing how satisfying a small victory like this feels.

[LaceyDucati]

Glad the battles won, I know that feeling well