Looking for guidannce - six stubborn bolts on crankcase

[McCabe-Thiele (Ted)]

Before I break a bolt or mangle the 12 mm heads looking for guidance as to how to remove these six bolts that have so far resisted my efforts.

1. I have sprayed with Plus Gas A after wire brushing heads.
2. Impact driver has not budged the last six bolts.

Any advice as to what to try next?


..stubborn bolts by Macabe Thiele, on Flickr

[taysidedragon]

Try some heat. Don't melt the ally.
More plusgas and leave overnight.

[McCabe-Thiele (Ted)]

Try some heat. Don't melt the ally.
More plusgas and leave overnight.

Good idea I have a basic plumbers blow torch so I will try heat from the bolt tops - then at least the plus gas might get past the bolt head when the paint has been burnt off.

[K2-K6]

Put other bolts around there back in and torque them.

Then try just a little to tighten first to see if the bolt head is stuck rather than the threads. Literally to see if they'll move at all before reversal to undo if they yeald.

[Bryanj]

Six sided impact socket and rattle gun, if they are that corroded into the alloy they willbreak no matter what you do

[philward]

Don't forget the socket/extension and crack with a hammer before attempting to remove. And copper based grease on re-assemble

[McCabe-Thiele (Ted)]

Six sided impact socket and rattle gun, if they are that corroded into the alloy they willbreak no matter what you do

I've not persisted with my cordless Kielder Impact gun as I do not want to risk rounding them off at this stage - I am going to apply some heat / Plus Gas formula A over the weekend then get a Mate who has a more powerful version of my tool - its a beast - an all metal Milwuakee Professional with Red Fuel Battery Technology it made short work of a wheel bolt that would not budge last year.

As you have said if it has corroded into the alloy it will break anyways - virtually impossible to get the releasing fluid to where it needs to be - just pray that the broken bits will eventually come out. The one in the sump worries me as I thought this one would let go easily. I guess these bolts are the ones that hold the crank firmly in place judging by their position.

[McCabe-Thiele (Ted)]

Don't forget the socket/extension and crack with a hammer before attempting to remove. And copper based grease on re-assemble

Yes Phil I did the hammer crack first - I am a big fan of Copper Grease but most torque settings are based on dry assembly unless you mean just grease the unthreaded part of the bolts.

[K2-K6]

The zinc plating does the non-seize protection bit and they coated all the fixings diligently in this way in a "but what did the Japanese do for us scenario"  but being sacrificial and subjected to British salty roads, there's obviously a limit to how much zinc survives over many years.

Ultimately it's wise to re-zinc them for a proper job.

[McCabe-Thiele (Ted)]

My mate Marco dropped in this afternoon with his young muscle and Milwuakee Power tool - took less than 2 minutes to remove all six bolts - he used some weird 12 mm socket that was multi sided and grabs the bolt head without chewing it up!

Obviously I must have loosened them with the heat cycle this morning. lol (clearly in denial).

This is the tool my Mate had https://www.sgs-engineering.com/m18onefhiwf12-553p-impact-wrench-with-packout-case

The socket he used looked at a glance like a standard 12 mm socket but instead of having normal flat sides they had a curved edge that sort of peaked in the centre of the flats when they removed a bolt it was a bit of a job to make it let go of the bolt - never seen them before.

[Bryanj]

I think they are called flanx drive

[McCabe-Thiele (Ted)]

I think they are called flanx drive

Thanks Bryanj that's what they were spelt Flank & Flank Plus!

https://www.youtube.com/watch?v=rvQAAd-gdE8