How do I get seized bolts out?

[losidan]

hi,

One of my crank arms is stuck on as the bolt which holds it onto the bb axle is seized solid.....

Does anyone have any tips on how I can get the blighter out?

Thanks
Dan

[ORB]

what kind of cranks are they?

This will give me a better idea as to what we are against.

Do you have a pic?

[oberonspacefruit]

liquid wrench-plusgas.

[losidan]

They are redline flights...It is the single bolt which threads into the BB axle

I dont even know what liquid wrench is 

[kuwahero]

are you using the right allen key as flights are imperial ie in inches.

spray it with loads of wd40 leave 15mins and do again. then get the right sized allen key and ring spanner or an old seatpost. place the ring spanner  or seat post over the end of the allen key as a lever and it should come off without to much trouble. if you have allen key bits for a socket set even better.

if they arent allen key bolts, which they should be use the right size socket with the ratchet spanner and the post on end as extra leverage

marc

[MartyC]

Get the right sized allen key from a drill bit set i.e. a straight allen key, put it in the bolt and give the allen key a whack with a hammer - be careful not to clout your cranks though.  This should break the "weld" between the bolt threads and the axle threads. then using a normal cranked allen key (with a 90 degree bend) undo said bolt  .

[oberonspacefruit]

Plus gas is a dismantling spray, sold at motor shops, penetrates over time, especially if continually applyed over a few days.

In my opinion it works better than wd40.

[steve Beech TA]

to look at it plus gas is simaler to wd40 but it does work better

[losidan]

ta chaps

[perry]

id go with martyc . plus soaking it in diesel ( but at the moment id guess the plug gas would be cheaper  )

but dont lose your rag with it , there will be a way to get them off no matter what ( so dont go mental and start swinging the hammer  )

[rooski]

you could use an impact driver the kind you hit with a hammer,after using plus gas etc, this shock loads the fastener as well as turning it at the same time. Each blow will only turn it a fraction so use a wrench when its free.

[TwoBobRob]

Yip.  All of the above.  Personally, I'd expect to snap that bolt more then likely so I'd go straight to the impact driver and start swinging....

Then drill and tap the axle again.