Giant Defy 3 (Tektro TK-R312) brake caliper bolt stuck

axer

Hi,

I have a Giant Defy 3 with Tektro TK-R312 brake calipers that I am trying to replace. The problem is that the center caliper bolt nut will not loosen at all. This is a photo of the caliper new. After much work (including penetrating oil etc) the head (hex) eventually ended up being stripped then I tried jamming a torx screw head into the head but even though it was very tight it also failed to open and resulted in an even more stripped head. Left with no other ideas I cut the bolt in the middle as I was not holding onto the caliper anyway. I thought then as the bolt doesn't screw into the frame that I could then tap through the bolt. The sawn off bolt and nut are still wedged in the frame hole as can be seen in the attached photo. The only thing I can think if being the issue here is galvanic corrosion or something like that.

Anyone come across something like this before?
Is my only option to drill through the remaining bolt?
Also to confirm, the hole in the frame wouldn't have a thread, right?

The bike is about 4.5 years old.

Thanks for any advice you can give.

py

Remove the wheel. Lace both sides with WD40 (or equivalent), leave for 10 minutes and then very gently "encourage" from the side it's been sheered off from. If it were me it be looking at something like a small flat head screwdriver with a rubber mallet for force.

I've had similar with my front calliper though never went as far as to cut it. I actually unscrewed the caliper itself as the bolt was stuck, once caliper was removed I used the above method and it worked. Good luck.

Alternatively drop it to your lbs.

Invincible

Use an easy-out* of suitable size in the Allen head, as you twist it anti-clockwise, the bolt will come out.

*Also called screw extractors.

Donnelly117

Plus one for screw extractors, Halfords sell a set that goes down to M3 which should sort you out!

axer

Thanks for the advice. I have it left with a lbs to see what they can do. I'm surprised how welded in it seems. Hopefully they can either use a screw extractor or drill it out. Looks like I need to take my bike apart more often and grease parts to stop this type of thing happening.

Invincible

Or use Copper slip, aka anti-seize compound.

axer

Invincible wrote: »

Or use Copper slip, aka anti-seize compound.

Would it be safe enough to do that once and expect it to last a few years even with washing the bike or would I still need to strip down the bike once a year?

Invincible

axer wrote: »

Invincible wrote: »

Or use Copper slip, aka anti-seize compound.

Would it be safe enough to do that once and expect it to last a few years even with washing the bike or would I still need to strip down the bike once a year?

It'll last a few year's, as it'll need scrubbing with degreaser to remove it.
How do you normally wash bike, light powerhosing and car shampoo?

axer

Invincible wrote: »

It'll last a few year's, as it'll need scrubbing with degreaser to remove it.
How do you normally wash bike, light powerhosing and car shampoo?

Yes, very light hosing down and a bucket of warm water with car shampoo.