F935, pulley removal - sheared bolt removal

Big Wave D · Mar 30, 2012

I am dealing with part 7.

I went online to Deere parts and it labels it as a tapered fit pulley. So it seems that I should be able to use a standard puller for removing it. Not going so well at the moment. Will heat help much? How 'rough' can I get with it in trying to remove it?

After getting it off, the second problem is removing the remainder of the bolt that is sheared off in one of the 3 thread cups. I haven't really tried anything since I've not gotten the part off; however, I am wonder about what other options I might have other than drilling and using an extractor. It is an M8 sized metric bolt, so not overly large, but I am wondering if it is possible to do the welding technique? If so, how? Am I literally trying to use the bolt as my "rod"? Don't want to screw up the threads.

Thanks for any tips or advice.

Big Wave D · Mar 30, 2012

Okay, as an update. I was able to use some 'gentle' heat and get the pulley to come free from the front of the crankshaft.

Now only 1 problem left, removing the old sheared bolt.

Is drilling and trying to use a bolt extractor my best or maybe, should I say, my only option?

I'd like someone to weigh in on the welding method. Is this to small a bolt to try this with? It's only an M8.

Thanks

Zebrafive · Mar 30, 2012

Is the bolt broken off above or below the pulley?
Blind hole or go all the way thru?

Big Wave D · Mar 30, 2012

The bolt is broken off just a few threads below the lip of the blind hole.

Have decided to go with the drill and extractor route. The bolt size just doesn't allow enough room to try and weld a smaller bolt to the remainder and not mess up the threads.

I know of PB Blaster or Kroil, but is there any other tricks for trying to get the remainder of the bolt to let loose?

I have heard of somehow using candle wax, but don't remember how it was explained to be used to help unsieze the stuck part.

zzvyb6 · Mar 30, 2012

Now that the pulley is off, is the remaining bolt stub loose enough that a small dental pic or chisel can work it out? The conditions of the other bolts should give you a hint. A small sharp center punch usually works for me. Can you get a hold of a reverse direction drill bit so that if it bites on the bolt it will unscrew it?

If you unbolt the motor mounts, you might be able to tip the engine upward enough to get a better working position view.

zzvyb6 · Mar 30, 2012

Since the pulley is off, no need to tip the motor. Manual indicates there is Loc-Tite on the threads, so heat it up to release the thread lock. A center punch then ought to back out the bolt fragment. If you can cut, grind or chop a slot in the stub, a screw driver ought to be able back it out, too.

Big Wave D · Mar 31, 2012

I saw that to, about the thread lock. It says medium body, so I hope I don't have to heat it up to cherry red or anything to have it let loose.

I have tried the pick and also an old nail set. Kind of had a little corner to work on, but it seems like it was only going to mess up the threads, so I stopped.

I did get and extractor to finally 'bite', but could tell it was only going to snap if I tried to force it any more. I have not added the heat yet and will today. I do hope that it will finally play nice and let loose so I can back the rest out.

Some one had already replaced one bolt with a substandard, 8.8. So, I am wondering it that is what got broke off. The did not use Lock-Tite for the other, so I am hopeful that the broke one doesn't have any either.

We'll see.

moored4 · Mar 31, 2012

zzvyb6 said:
Now that the pulley is off, is the remaining bolt stub loose enough that a small dental pic or chisel can work it out? The conditions of the other bolts should give you a hint. A small sharp center punch usually works for me. Can you get a hold of a reverse direction drill bit so that if it bites on the bolt it will unscrew it?

zzvyb6 said:
Since the pulley is off, no need to tip the motor. Manual indicates there is Loc-Tite on the threads, so heat it up to release the thread lock. A center punch then ought to back out the bolt fragment. If you can cut, grind or chop a slot in the stub, a screw driver ought to be able back it out, too.

I would start reverse drilling just enough to get a hole started and then heat it up, then while its hot from the heating prosses then finishing drilling and cross your fingers that it will back out whill drilling it! GOOD LUCK! :thumbsup:

Big Wave D · Mar 31, 2012

moored4,

I just bought some reverse drill bits yesterday. Had to put the project on hold because of already made plans for Friday evening.

I am going to use heat and see if the extractor that is 'anchored' in the remaining bolt will do anything. If it doesn't, then I will give your heat and l.h. drilling a try next.

Thanks to all for the advice and well wishes. :thumbsup: