Crank case bolt

I am trying to split the crank case, but one of the 6mm bolts on the right hand side has been rather stubborn. The rest were fine with a normal socket, but the one at the back is more enclosed. I've tried a box socket over it, but I think it's been a little chewed up previously and my first attempt did not go well. It's the one at to bottom near the rear of the case. Any ideas for getting this out?

[DJ123]

Have you put some plus gas or other penetrating fluid on it?

I've given it a few squirts of wd40.

[maviczap]

Wd40 isnt the ideal stuff as it isnt a penetrant.

As for the bolt, i'd whack it on the head using a centre punch just to loose the threads. Id also try warming the area around it, if you can

Id buy a deep 6 sided socket that grips the bolt on the faces, not the corners and use it with an impact wrench. I wouldnt use too much force, as its likely to shear.

I've probably given a bad description. I don't think the bolt will be too stuck, the rest have been ok, but because this was more recessed I've rounded the corners a bit more. I got a box spanner, basically like a very deep 6 sided socket, but it's not really gripping the head of the bolt any more.

[maviczap]

Might have to cut a slot in the head if you can, but I'd still go for a quality 6 sided socket first, a box spanner will always be a sloppy fit

Pics would help

[punyXpress]

If it's the long burger that goes through both halves of the case, have you removed the nut from the other end?

No its not the long one. I'll get a photo tomorrow. The main problem has been that my normal socket didn't fit straight over, but at an angle, it wasn't a problem for the 8 other bolts, but this is more enclosed. I need a thinner socket to get over it properly. At that point it may have purchase enough. Also not a bi-hex.

Wera Joker spanner might help here.

https://www.youtube.com/watch?v=BvBmCqXDDdk

Either that or a good star socket that'll grip the sides, rather than the corners of the bolt, as already mentioned.

IF it's stubborn and of a small enough size, i've had success with a cordless drill/driver with adjustable torque, and turned the torque up slowly with a suitable socket adaptor attachment, it'll eventually "shock" it free.
Failing that impact driver would be my next port of call.
Alternatively drill it out, buy a new one, use molegrips to turn it out once apart.

Got a 8mm deep drive with a 1/4" drive, came right out. Thanks for the advice Mavic. I have now discovered that one of my con rod bearings has disintegrated.