F1 bleed nipple thread stripped

[Grewth]

I found quite a nice looking caliper for my F1, piston came out easily.
No such luck with the bleed nipple.
Roasted the caliper body on the gas hob, my usual trick, the nipple did unscrew (well sort of), but ripped the thread out of the caliper body on its way out.
Oh well, that's better than the nipple shearing off in the caliper.
Now I'm thinking maybe I could drill oversized and tap for an oversized nipple.
Or maybe a helicoil insert  (although I really don't like them) ?
Is there any economically viable repair possible  ?
Or do I have a lump of scrap aluminium  ?

[K2-K6]

You can get proprietary repair kit to recover the casting.

Example of https://www.ebay.co.uk/itm/227284064706 that puts a durable insert into a larger bore. Then the bleed nipple runs on those thread for functional use.

[Skoti]

I found quite a nice looking caliper for my F1, piston came out easily.
No such luck with the bleed nipple.
Roasted the caliper body on the gas hob, my usual trick, the nipple did unscrew (well sort of), but ripped the thread out of the caliper body on its way out.
Oh well, that's better than the nipple shearing off in the caliper.
Now I'm thinking maybe I could drill oversized and tap for an oversized nipple.
Or maybe a helicoil insert  (although I really don't like them) ?
Is there any economically viable repair possible  ?
Or do I have a lump of scrap aluminium  ?

Years ago mines done the same, managed to drill it out and fit an oversize nipple.
Think it was M8x1.0, because I had to buy a tap specially for the job.

Remember to only drill to 7mm or less before inserting the tap, that allows for decent deep strong thread, the alloy is very soft and shity.

Good luck

 

[Bryanj]

I have some Napa repair kits where  you drill and tap to 1/8 npt but i am in usa till early may

[Grewth]

Many thanks for all the replies.
I've been doing some research myself and ended up buying a pair of replacement inserts and a M9 x1 tap set.
Then I tried drilling out the sheared bleed nipple on the F1 caliper I'd stashed at work, and it was an was an absolute nightmare.
So now that caliper body is tapped M10 x1 thanks to a 9mm drill and a tap borrowed from a workmate.
Got to order two M10 x 1 inserts now, another £11, but still pretty small beer really.
So now at least I know that I can use an M10 insert in a F1 caliper.
Hopefully everything will be pretty straightforward after this.
New stainless piston,  new seals, new lines, master cylinder repair kit.
What could possibly go wrong  ?

[Bryanj]

ER.       Getting the master apart!!

[Grewth]

ER.       Getting the master apart!!

I usually resort to the gas cooker hob for this job.
A bit drastic but the troublesome circlip usually surrenders a lot sooner when given a good roasting first.

[Skoti]

ER.       Getting the master apart!!

I usually resort to the gas cooker hob for this job.
A bit drastic but the troublesome circlip usually surrenders a lot sooner when given a good roasting first.

Usually I start with a small pin punch and gently tap round the circumference of the circlip, which seems to help loosen it's grip.
Then I use a hook and pick set to lever it free before the circlip pliers go in.

Good luck