Needed to change the rear disc on the Gen 2 FZ1 and had been warned that it can be difficult to get the bolts undone.....
So soaked the threads in Plus Gas, froze the bolts (instead of warming the hub) to shrink them down, tapped them with large diameter pin punch to upset them and then tried to undo them...
2 undid ok, 2 T40 heads snapped off flush in the bolt heads and couldn't be removed, the other snapped off but did come out. What to do as the T40 heads are too hard to drill?
So welded M16 nuts to the bold heads and they undid fine with no damage to the hub (serious thermal shock helped). Not sure what else I could have done - may also work for the front discs as I've heard that the whole wheel gets thrown away if they can't get the bolts out.
The design of the bolt heads is wrong - the ratio of the T40 diameter to the bolt diameter means if the bolt is at all seized it's then very likely the T40 will fail - I used reasonably quality T40 heads...
So soaked the threads in Plus Gas, froze the bolts (instead of warming the hub) to shrink them down, tapped them with large diameter pin punch to upset them and then tried to undo them...
2 undid ok, 2 T40 heads snapped off flush in the bolt heads and couldn't be removed, the other snapped off but did come out. What to do as the T40 heads are too hard to drill?
So welded M16 nuts to the bold heads and they undid fine with no damage to the hub (serious thermal shock helped). Not sure what else I could have done - may also work for the front discs as I've heard that the whole wheel gets thrown away if they can't get the bolts out.
The design of the bolt heads is wrong - the ratio of the T40 diameter to the bolt diameter means if the bolt is at all seized it's then very likely the T40 will fail - I used reasonably quality T40 heads...