Front brake caliper

[hank]

Simple job gone bad. Checked the bike over before booking an M.O.T test and decided I need a new front tyre. While removing the front wheel from my 1150R this morning I broke the lower bolt that holds the brake caliper to the forks.

There is about a quarter of an inch of thread showing which I have now wrecked by using mole grips. Next atack on the stubborn git was to try drilling it through the centre and gradually increase the size of drill as I went. Guess what happened next? Bloody drill broke inside the hole with no chance of removal.

Are there any other options for getting the broken bolt out or should I just buy second hand caliper?
Good job I don't have any trips planned this weekend, but I will have to cancel my M.O.T appointment untill I get the brakes fixed.

I was always told not to lube these bolts as they had to be tightened to a specific torque, but you can bet when I put it back together the bolts will be lubed and tightened by feel.

 

[Carefulkev]

Any chance of drilling it from the other side? - if your really lucky it might even unscrew the bolt as it goes

 

[sockpuppet]

Might be easier to take it to an engineering firm and get them to do the dirty for £20 or so.

I'd drill a sizeable holein the other side of the bolt and smack a torx bit in there and use that to wind it out.

 

[MattW]

Might be easier to take it to an engineering firm and get them to do the dirty for £20 or so.

I'd drill a sizeable holein the other side of the bolt and smack a torx bit in there and use that to wind it out.

Yup - a spark erosion machine will be your saviour.
Call your local engineering shop.

 

[hank]

Yup - a spark erosion machine will be your saviour.
Call your local engineering shop.

Went to my mates for a barbeque on Friday night, while sitting round the fire pit having a few beers his nephew arrived, the nephew is an engineer. So caliper is going in tomorrow for the spark treatment and a retap. Should I remove the pistons from the caliper before it goes to the shop?

 

[MattW]

Went to my mates for a barbeque on Friday night, while sitting round the fire pit having a few beers his nephew arrived, the nephew is an engineer. So caliper is going in tomorrow for the spark treatment and a retap. Should I remove the pistons from the caliper before it goes to the shop?

Spark erosion is done under a fluid but I'm not sure if the fluid will harm the seals. It's usually a type of oil but it'll depend on the machine in question.

If you can seal up the brake hose connection so that nothing can enter the caliper, I'd leave it assembled but otherwise it might be better to remove the pistons and possibly budget for a new set of seals.

Others may know more...

 

[hank]

Just got my brake caliper back from my young engineer friend. He was able to drill out the old bolt and broken drill bit and has run a tap down the threads. Will now order new bolts and re-fit to the bike.

But first I am off to the shop to buy him a bottle of Jack Daniels as he is refusing to take any payment.

 

[MattW]

Just got my brake caliper back from my young engineer friend. He was able to drill out the old bolt and broken drill bit and has run a tap down the threads. Will now order new bolts and re-fit to the bike.

But first I am off to the shop to buy him a bottle of Jack Daniels as he is refusing to take any payment.

Excellent