Stuck allen bolts - drastic action

[pete]

Hi all, I've been trying on and off for many months to get the two allen bolts out of the oil filter housing on my '81 450 with no success.

So far, I've broken three allen keys, tried the heat/cool thing, whacking the end of a long allen key bit with a hammer, and so on, but they still won't budge.

My last resort is to drill the heads off the things.

These are the last two bolts stopping me pulling the crank cases apart.

Aside from the obvious extreme caution when drilling, is there anything else I should be taking care with when doing this?

Photo below shows the bolts (in the bottom as it's upside down to work on):

[jmanz6]

How do you propose to drill them when you can't get a straight shot at them? What did you use to heat them? You need more heat. I bet there is thread locker on them and they need to be pretty hot in order for it to break down. Heat them until they start to glow red, then use an allen key to get them out. Insulate your hand from teh wrench as it will conduct heat very quickly from the bolt to the wrench and to your hand. Also might try some PB Blaster to see if it can work it's way down there but since it's not a rusted bolt I think heat is the best option.

[SqDancerLynn1]

Good quality allen wrench, & short length of pipe should do it.

[pete]

There's access holes in the bottom of the crankcase, so hopefully a drill bit will be long enough to get through.

I didn't heat them quite that much! I wasn't game to heat them up too much as I didn't want to warp anything, I might try that again first.

And I have a new set of allen keys that are high tensile heat treated etc. and haven't been damaged compared to the other three I had, but even with a pipe over the end they still won't budge, but perhaps with even more heat they will.

Cheers for the tips guys, will see how it goes hopefully tomorrow.

[p_s]

I like the allen-key sockets for these problems.

[scotschult]

One step better than a wrench & pipe is an allen head socket, like below (pic stolen from ebay), and your trusty impact driver. Worst case is you'll have to buy a set, but see if there's an auto parts store near you that rents, or loans, tools. They may have what you need.


Edit: Whoops!! p_s beat me to it. Sorry....

[pete]

One of the allen keys I busted was a supposedly high tensile socket like those... perhaps it just wasn't as tough as advertised!

Will see how the heating goes again tomorrow and I'm unfortunately very short of good hardware stores near me as the best one doesn't even open on Sundays!

[atvpyrofreak]

I'll second (or 3rd) whats been said. Get some allen head sockets, a short extension to get through the case, and an impact driver. Add some heat and they should come right out.

[trippivot]

with the access holes a matco or snap on extractor set is just the ticket.
not the long tapered type , the short ones with cutting teeth on the end and sides. they will grip the inside of the allen recess.

I guess it is a moot point to say not enough heat OR enough shock was used to free the bolts.

[Matchless]

with the access holes a matco or snap on extractor set is just the ticket.
not the long tapered type , the short ones with cutting teeth on the end and sides. they will grip the inside of the allen recess.

I guess it is a moot point to say not enough heat OR enough shock was used to free the bolts.

An air impact driver with an allen socket is the only safe method that I would use. If you do not have one take the parts to a workshop, it will be cheaper than if you damage something.

[Old Colt]

I agree that an Allen socket is the way to go here. A wrench with pipe puts the loads in at an angle where you can get a straight rotation with a socket.

That area of the case has so much mass that heating will be of little value. You just are not going to heat it enough. The heat needs to get to the threads and I doubt you are getting it warm down there. You probably can though.

To me, using a real brand name socket matters, I do not care what marketing speak is used with all the others but most of them are not heat treated properly and impose a greater chance of simply snapping or worse, rounding out the head of the fastener.
A Snapon, Mac or Matco will hold up better than most any other brand. If they are not easily accessible to you look on eBay, you might find one or a set in short time.

You may want to give the bolts a whap with a drift and hammer to loosen them a bit. This can be done right through the socket too with or without an impact driver. If doing this this through the socket, make sure the socket will take the end loads. many wont.

[bwringer]

I used an air impact and a long allen socket.



(The allen socket was from... Harbor Freight. But it worked!)

[Cassius086]

liberal doses of PB blaster, and an appropriate allen head socket.

Good luck!!

[rudy]

Hey, just thought I'd jump on the band wagon and say get a good set of allen sockets. And try an impact as well. If you can get an air impact, try the impact driver. You'd be surprised what you can get out with them.

If these are stainless bolts in aluminum, things could be bad, as the two metals react to each other over time. But being in the crankcase, it shouldn't bee that bad, as the reaction needs water as well.

[Calvin Blackmore]

I'll second (or 3rd) whats been said. Get some allen head sockets, a short extension to get through the case, and an impact driver. Add some heat and they should come right out.

What he said only perhaps on the end of a three foot bar

and dotn apply constant increasing pressure

give it a short sharp full stenght snap
maybe having a fiend force the bit into the hole so you can concentrate on levering

mind you the wretched things may have fused to the threads via the good old galvanic corrosion

if that is the case and you cant get a straight shot in the frame with a nice normal drill would a right agnle drill work?

can you get the engine out
I would perfer to drill without encumberances
in my exp an allen head lends itself nicely to drilling so long as you will buy some good new bits that are smaller than the diameter of the bolt shaft you should be OK

anythime I have had to do this you get to a point where it is as if pressure is relieved on the threads and the bolt often spins out by hand