Hollow Tech II Problems - Please Help

[ollietrex]

I have been working on replacing the front crank rings on my crank which is an XT Hollow Tech II. In doing this I need to remove the once piece crank which requires undoing two bolts on the opposite side to the crank rings which hold everything together.


http://www.parktool.com/images_inc/repair_help/hollowtech19.jpg


When I was doing this I used a 5mm hex and started turning it and it instantly started to strip the inside of the hex bolt so it seems it was probably a dud hex or a very soft metal. So I have two problems:-


1) Any one know if those bolts are steel of aluminum and a good way to remove them?

2) Can you buy the bolts without the crank or do I have to buy a new crank?

[Morgan]

The bolt was probably a little siezed. The hex-key could also be a bit worn around the edges.


You should be able to get new bolts, the part number is listed here (http://cycle.shimano-eu.com/media/techdocs/content/cycle/EV/bikecomponents/FC/EV-FC-M760-2261D_v1_m56577569830608893.pdf). If you can't get them new I'm sure there are plenty of worn-out cranks around that you could get one from. As a last resort you could get a new arm (http://www.chainreactioncycles.com/Models.aspx?ModelID=12509).


To get it out try tightening the other bolt a bit (might reduce pressure on this one). A spray of WD-40 to loosen things up. Try using a new hex-key to remove it. If it's totally stripped it can be removed using an "easy-out" or by drilling.

[paddyobrien]

ollie i may have some bolts from an old HTII lying around

[ollietrex]

They are a Clamp Bolt (M6 x 19) which I am guessing is a M6 which is 19mm long so should be able to get these no hassle.


Am I going to find any more problems trying to remove the whole crank arm out as shown in:-


http://cycle.shimano-eu.com/.../EV-FC-M760-2261D_v1_m56577569830608893.pdf (http://cycle.shimano-eu.com/media/techdocs/content/cycle/EV/bikecomponents/FC/EV-FC-M760-2261D_v1_m56577569830608893.pdf)


All I want to do is put some new bloody chain rings on...

[paddyobrien]

Well first off let me just say that you only need to take this off if you want to replace the granny ring .. you can replace the other two with the whoel cranke system still in place.


Other than that though its no bother. Undo the two bolts, remove the plastic tension screw thingy (part 1 on that diagram). take off the non drive side crank.


The rest of the crank may not want to come out, if this is the case you'll need to gently persuade it out. a good way to do this is to put a block of wood over the non drive side of the crank axle, and then use a hammer to gently tap it out.


Well, start gentle, and work your way up to giving it a good whack. It'll move at some point.

[ollietrex]

Yep the granny ring and everything needs to be changed. For the engineers of us all does any one know if the M6 bolts have a standard thread width on bikes these days as I know a few years ago there used to be a cycle thread width?

[Sean]

er, what were you doing using the granny ring anyway?

[Barrydanzig]

yeah, thats unnecessary weight there ollie!